pair_airebo.cpp
8fb52958cee3lammm-master

pair_airebo.cpp
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			/* ----------------------------------------------------------------------
			LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
			http://lammps.sandia.gov, Sandia National Laboratories
			Steve Plimpton, sjplimp@sandia.gov

			Copyright (2003) Sandia Corporation. Under the terms of Contract
			DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
			certain rights in this software. This software is distributed under
			the GNU General Public License.

			See the README file in the top-level LAMMPS directory.
			------------------------------------------------------------------------- */

			/* ----------------------------------------------------------------------
			Contributing author: Ase Henry (MIT)
			------------------------------------------------------------------------- */

			#include "math.h"
			#include "stdio.h"
			#include "stdlib.h"
			#include "string.h"
			#include "mpi.h"
			#include "pair_airebo.h"
			#include "atom.h"
			#include "neighbor.h"
			#include "neigh_request.h"
			#include "force.h"
			#include "comm.h"
			#include "neighbor.h"
			#include "neigh_list.h"
			#include "neigh_request.h"
			#include "memory.h"
			#include "error.h"

			using namespace LAMMPS_NS;

			#define MIN(a,b) ((a) < (b) ? (a) : (b))
			#define MAX(a,b) ((a) > (b) ? (a) : (b))

			#define MAXLINE 1024
			#define TOL 1.0e-9
			#define PI 3.14159265
			#define PGDELTA 1

			/* ---------------------------------------------------------------------- */

			PairAIREBO::PairAIREBO(LAMMPS *lmp) : Pair(lmp)
			{
			single_enable = 0;
			one_coeff = 1;

			maxlocal = 0;
			REBO_numneigh = NULL;
			REBO_firstneigh = NULL;
			maxpage = 0;
			pages = NULL;
			nC = nH = NULL;
			}

			/* ----------------------------------------------------------------------
			check if allocated, since class can be destructed when incomplete
			------------------------------------------------------------------------- */

			PairAIREBO::~PairAIREBO()
			{
			memory->sfree(REBO_numneigh);
			memory->sfree(REBO_firstneigh);
			for (int i = 0; i < maxpage; i++) memory->sfree(pages[i]);
			memory->sfree(pages);
			delete [] nC;
			delete [] nH;

			if (allocated) {
			memory->destroy_2d_int_array(setflag);
			memory->destroy_2d_double_array(cutsq);

			memory->destroy_2d_double_array(cutljsq);
			memory->destroy_2d_double_array(lj1);
			memory->destroy_2d_double_array(lj2);
			memory->destroy_2d_double_array(lj3);
			memory->destroy_2d_double_array(lj4);
			delete [] map;
			}
			}

			/* ---------------------------------------------------------------------- */

			void PairAIREBO::compute(int eflag, int vflag)
			{
			if (eflag \|\| vflag) ev_setup(eflag,vflag);
			else evflag = vflag_fdotr = 0;

			// error check (for now)

			if (eflag_atom \|\| vflag_atom)
			error->all("Pair style airebo does not yet support peratom energy/virial");

			REBO_neigh();
			FREBO(eflag,vflag);
			if (ljflag) FLJ(eflag,vflag);
			if (torflag) TORSION(eflag,vflag);

			if (vflag_fdotr == 2) virial_compute();
			}

			/* ----------------------------------------------------------------------
			allocate all arrays
			------------------------------------------------------------------------- */

			void PairAIREBO::allocate()
			{
			allocated = 1;
			int n = atom->ntypes;

			setflag = memory->create_2d_int_array(n+1,n+1,"pair:setflag");
			for (int i = 1; i <= n; i++)
			for (int j = i; j <= n; j++)
			setflag[i][j] = 0;

			cutsq = memory->create_2d_double_array(n+1,n+1,"pair:cutsq");

			// only sized by C,H = 2 types

			cutljsq = memory->create_2d_double_array(2,2,"pair:cutljsq");
			lj1 = memory->create_2d_double_array(2,2,"pair:lj1");
			lj2 = memory->create_2d_double_array(2,2,"pair:lj2");
			lj3 = memory->create_2d_double_array(2,2,"pair:lj3");
			lj4 = memory->create_2d_double_array(2,2,"pair:lj4");

			map = new int[n+1];
			}

			/* ----------------------------------------------------------------------
			global settings
			------------------------------------------------------------------------- */

			void PairAIREBO::settings(int narg, char **arg)
			{
			if (narg != 1 && narg != 3) error->all("Illegal pair_style command");

			cutlj = atof(arg[0]);

			ljflag = torflag = 1;
			if (narg == 3) {
			ljflag = atoi(arg[1]);
			torflag = atoi(arg[2]);
			}
			}

			/* ----------------------------------------------------------------------
			set coeffs for one or more type pairs
			------------------------------------------------------------------------- */

			void PairAIREBO::coeff(int narg, char **arg)
			{
			if (!allocated) allocate();

			if (narg != 3 + atom->ntypes)
			error->all("Incorrect args for pair coefficients");

			// insure I,J args are * *

			if (strcmp(arg[0],"") != 0 \|\| strcmp(arg[1],"") != 0)
			error->all("Incorrect args for pair coefficients");

			// read args that map atom types to C and H
			// map[i] = which element (0,1) the Ith atom type is, -1 if NULL

			for (int i = 3; i < narg; i++) {
			if (strcmp(arg[i],"NULL") == 0) {
			map[i-2] = -1;
			continue;
			} else if (strcmp(arg[i],"C") == 0) {
			map[i-2] = 0;
			} else if (strcmp(arg[i],"H") == 0) {
			map[i-2] = 1;
			} else error->all("Incorrect args for pair coefficients");
			}

			// read potential file and initialize fitting splines

			read_file(arg[2]);
			spline_init();

			// clear setflag since coeff() called once with I,J = * *

			int n = atom->ntypes;
			for (int i = 1; i <= n; i++)
			for (int j = i; j <= n; j++)
			setflag[i][j] = 0;

			// set setflag i,j for type pairs where both are mapped to elements

			int count = 0;
			for (int i = 1; i <= n; i++)
			for (int j = i; j <= n; j++)
			if (map[i] >= 0 && map[j] >= 0) {
			setflag[i][j] = 1;
			count++;
			}

			if (count == 0) error->all("Incorrect args for pair coefficients");
			}

			/* ----------------------------------------------------------------------
			init specific to this pair style
			------------------------------------------------------------------------- */

			void PairAIREBO::init_style()
			{
			if (atom->tag_enable == 0)
			error->all("Pair style AIREBO requires atom IDs");
			if (force->newton_pair == 0)
			error->all("Pair style AIREBO requires newton pair on");

			// need a full neighbor list

			int irequest = neighbor->request(this);
			neighbor->requests[irequest]->half = 0;
			neighbor->requests[irequest]->full = 1;

			// local REBO neighbor list memory

			pgsize = neighbor->pgsize;
			oneatom = neighbor->oneatom;
			if (maxlocal == 0) add_pages(0);
			}

			/* ----------------------------------------------------------------------
			init for one type pair i,j and corresponding j,i
			------------------------------------------------------------------------- */

			double PairAIREBO::init_one(int i, int j)
			{
			if (setflag[i][j] == 0) error->all("All pair coeffs are not set");

			// convert to C,H types

			int ii = map[i];
			int jj = map[j];

			// use C-C values for these cutoffs since C atoms are biggest

			// cut3rebo = 3 REBO distances

			cut3rebo = 3.0 * rcmax[0][0];

			// cutljrebosq = furthest distance from an owned atom a ghost atom can be
			// to need its REBO neighs computed
			// interaction = M-K-I-J-L-N with I = owned and J = ghost
			// this insures N is in the REBO neigh list of L
			// since I-J < rcLJmax and J-L < rmax

			double cutljrebo = rcLJmax[0][0] + rcmax[0][0];
			cutljrebosq = cutljrebo * cutljrebo;

			// cutmax = furthest distance from an owned atom
			// at which another atom will feel force, i.e. the ghost cutoff
			// for REBO term in potential:
			// interaction = M-K-I-J-L-N with I = owned and J = ghost
			// I to N is max distance = 3 REBO distances
			// for LJ term in potential:
			// short interaction = M-K-I-J-L-N with I = owned, J = ghost, I-J < rcLJmax
			// rcLJmax + 2*rcmax, since I-J < rcLJmax and J-L,L-N = REBO distances
			// long interaction = I-J with I = owned and J = ghost
			// cutlj*sigma, since I-J < LJ cutoff

			double cutmax = cut3rebo;
			if (ljflag) {
			cutmax = MAX(cutmax,rcLJmax[0][0] + 2.0*rcmax[0][0]);
			cutmax = MAX(cutmax,cutlj*sigma[0][0]);
			}

			cutsq[i][j] = cutmax * cutmax;
			cutljsq[ii][jj] = cutljsigma[ii][jj] cutlj*sigma[ii][jj];
			lj1[ii][jj] = 48.0 * epsilon[ii][jj] * pow(sigma[ii][jj],12.0);
			lj2[ii][jj] = 24.0 * epsilon[ii][jj] * pow(sigma[ii][jj],6.0);
			lj3[ii][jj] = 4.0 * epsilon[ii][jj] * pow(sigma[ii][jj],12.0);
			lj4[ii][jj] = 4.0 * epsilon[ii][jj] * pow(sigma[ii][jj],6.0);

			cutsq[j][i] = cutsq[i][j];
			cutljsq[jj][ii] = cutljsq[ii][jj];
			lj1[jj][ii] = lj1[ii][jj];
			lj2[jj][ii] = lj2[ii][jj];
			lj3[jj][ii] = lj3[ii][jj];
			lj4[jj][ii] = lj4[ii][jj];

			return cutmax;
			}

			/* ----------------------------------------------------------------------
			create REBO neighbor list from main neighbor list
			REBO neighbor list stores neighbors of ghost atoms
			------------------------------------------------------------------------- */

			void PairAIREBO::REBO_neigh()
			{
			int i,j,ii,jj,m,n,inum,jnum,itype,jtype;
			double xtmp,ytmp,ztmp,delx,dely,delz,rsq,dS;
			int ilist,jlist,numneigh,*firstneigh;
			int *neighptr;

			double **x = atom->x;
			int *type = atom->type;
			int nlocal = atom->nlocal;
			int nall = nlocal + atom->nghost;

			if (nall > maxlocal) {
			maxlocal = atom->nmax;
			memory->sfree(REBO_numneigh);
			memory->sfree(REBO_firstneigh);
			delete [] nC;
			delete [] nH;
			REBO_numneigh = (int *)
			memory->smalloc(maxlocal*sizeof(int),"AIREBO:numneigh");
			REBO_firstneigh = (int **)
			memory->smalloc(maxlocalsizeof(int ),"AIREBO:firstneigh");
			nC = new double[maxlocal];
			nH = new double[maxlocal];
			}

			inum = list->inum;
			ilist = list->ilist;
			numneigh = list->numneigh;
			firstneigh = list->firstneigh;

			// initialize ghost atom references to -1

			for (i = nlocal; i < nall; i++) REBO_numneigh[i] = -1;

			// store all REBO neighs of owned atoms
			// scan full neighbor list of I
			// if J is ghost and within LJ cutoff:
			// flag it via REBO_numneigh so its REBO neighbors will be stored below
			// REBO requires neighbors of neighbors of i,j in each i,j LJ interaction

			npage = 0;
			int npnt = 0;

			for (ii = 0; ii < inum; ii++) {
			i = ilist[ii];

			if (pgsize - npnt < oneatom) {
			npnt = 0;
			npage++;
			if (npage == maxpage) add_pages(npage);
			}
			neighptr = &pages[npage][npnt];
			n = 0;

			xtmp = x[i][0];
			ytmp = x[i][1];
			ztmp = x[i][2];
			itype = map[type[i]];
			nC[i] = nH[i] = 0.0;
			jlist = firstneigh[i];
			jnum = numneigh[i];

			for (jj = 0; jj < jnum; jj++) {
			j = jlist[jj];
			jtype = map[type[j]];
			delx = xtmp - x[j][0];
			dely = ytmp - x[j][1];
			delz = ztmp - x[j][2];
			rsq = delxdelx + delydely + delz*delz;

			if (rsq < rcmaxsq[itype][jtype]) {
			neighptr[n++] = j;
			if (jtype == 0)
			nC[i] += Sp(sqrt(rsq),rcmin[itype][jtype],rcmax[itype][jtype],dS);
			else
			nH[i] += Sp(sqrt(rsq),rcmin[itype][jtype],rcmax[itype][jtype],dS);
			}
			if (j >= nlocal && rsq < cutljrebosq) REBO_numneigh[j] = i;
			}

			REBO_firstneigh[i] = neighptr;
			REBO_numneigh[i] = n;
			npnt += n;
			if (npnt >= pgsize)
			error->one("Neighbor list overflow, boost neigh_modify one or page");
			}

			// store REBO neighs of ghost atoms that have been flagged in REBO_numneigh
			// find by scanning full neighbor list of owned atom M that is neighbor of I

			for (i = nlocal; i < nall; i++) {

			if (pgsize - npnt < oneatom) {
			npnt = 0;
			npage++;
			if (npage == maxpage) add_pages(npage);
			}
			neighptr = &pages[npage][npnt];
			n = 0;

			xtmp = x[i][0];
			ytmp = x[i][1];
			ztmp = x[i][2];
			itype = map[type[i]];
			nC[i] = nH[i] = 0.0;
			m = REBO_numneigh[i];
			if (m < 0) {
			REBO_firstneigh[i] = neighptr;
			REBO_numneigh[i] = 0;
			continue;
			}

			jtype = map[type[m]];
			delx = xtmp - x[m][0];
			dely = ytmp - x[m][1];
			delz = ztmp - x[m][2];
			rsq = delxdelx + delydely + delz*delz;

			neighptr[n++] = m;
			if (jtype == 0)
			nC[i] += Sp(sqrt(rsq),rcmin[itype][jtype],rcmax[itype][jtype],dS);
			else
			nH[i] += Sp(sqrt(rsq),rcmin[itype][jtype],rcmax[itype][jtype],dS);

			jlist = firstneigh[m];
			jnum = numneigh[m];

			for (jj = 0; jj < jnum; jj++) {
			j = jlist[jj];
			if (j == i) continue;
			jtype = map[type[j]];
			delx = xtmp - x[j][0];
			dely = ytmp - x[j][1];
			delz = ztmp - x[j][2];
			rsq = delxdelx + delydely + delz*delz;

			if (rsq < rcmaxsq[itype][jtype]) {
			neighptr[n++] = j;
			if (jtype == 0)
			nC[i] += Sp(sqrt(rsq),rcmin[itype][jtype],rcmax[itype][jtype],dS);
			else
			nH[i] += Sp(sqrt(rsq),rcmin[itype][jtype],rcmax[itype][jtype],dS);
			}
			}

			REBO_firstneigh[i] = neighptr;
			REBO_numneigh[i] = n;
			npnt += n;
			if (npnt >= pgsize)
			error->one("Neighbor list overflow, boost neigh_modify one or page");
			}
			}

			/* ----------------------------------------------------------------------
			REBO forces and energy
			------------------------------------------------------------------------- */

			void PairAIREBO::FREBO(int eflag, int vflag)
			{
			int i,j,k,m,itype,jtype;
			double delx,dely,delz,evdwl,fpair;
			double rsq,rij,wij;
			double Qij,Aij,alphaij,VR,pre,dVRdi,VA,term,bij,dVAdi,dVA;
			double dwij,del[3];
			int *REBO_neighs;

			evdwl = 0.0;

			double **x = atom->x;
			double **f = atom->f;
			int *type = atom->type;
			int *tag = atom->tag;
			int nlocal = atom->nlocal;
			int newton_pair = force->newton_pair;

			// two-body interactions from REBO neighbor list, skip half of them

			for (i = 0; i < nlocal; i++) {
			itype = map[type[i]];
			REBO_neighs = REBO_firstneigh[i];

			for (k = 0; k < REBO_numneigh[i]; k++) {
			j = REBO_neighs[k];
			if (tag[i] > tag[j]) continue;
			jtype = map[type[j]];

			delx = x[i][0] - x[j][0];
			dely = x[i][1] - x[j][1];
			delz = x[i][2] - x[j][2];
			rsq = delxdelx + delydely + delz*delz;
			rij = sqrt(rsq);
			wij = Sp(rij,rcmin[itype][jtype],rcmax[itype][jtype],dwij);
			if (wij <= TOL) continue;

			Qij = Q[itype][jtype];
			Aij = A[itype][jtype];
			alphaij = alpha[itype][jtype];

			VR = wij(1.0+(Qij/rij)) Aijexp(-alphaijrij);
			pre = wijAij exp(-alphaij*rij);
			dVRdi = pre * ((-alphaij)-(Qij/rsq)-(Qij*alphaij/rij));
			dVRdi += VR/wij * dwij;

			VA = dVA = 0.0;
			for (m = 0; m < 3; m++) {
			term = -wij * BIJc[itype][jtype][m] * exp(-Beta[itype][jtype][m]*rij);
			VA += term;
			dVA += -Beta[itype][jtype][m] * term;
			}
			dVA += VA/wij * dwij;
			del[0] = delx;
			del[1] = dely;
			del[2] = delz;
			bij = bondorder(i,j,del,rij,VA,f);
			dVAdi = bij*dVA;

			fpair = -(dVRdi+dVAdi) / rij;
			f[i][0] += delx*fpair;
			f[i][1] += dely*fpair;
			f[i][2] += delz*fpair;
			f[j][0] -= delx*fpair;
			f[j][1] -= dely*fpair;
			f[j][2] -= delz*fpair;

			if (eflag) evdwl = VR + bij*VA;
			if (evflag) ev_tally(i,j,nlocal,newton_pair,
			evdwl,0.0,fpair,delx,dely,delz);
			}
			}
			}

			/* ----------------------------------------------------------------------
			compute LJ forces and energy
			find 3- and 4-step paths between atoms I,J via REBO neighbor lists
			------------------------------------------------------------------------- */

			void PairAIREBO::FLJ(int eflag, int vflag)
			{
			int i,j,k,m,ii,jj,kk,mm,inum,jnum,itype,jtype,ktype,mtype;
			int atomi,atomj,atomk,atomm;
			int testpath,npath,done;
			double evdwl,fpair;
			double rsq,best,wik,wkm,cij,rij,dwij,dwik,dwkj,dwkm,dwmj;
			double delij[3],rijsq,delik[3],rik,delkj[3];
			double rkj,wkj,dC,VLJ,dVLJ,VA,Str,dStr,Stb;
			double delkm[3],rkm,delmj[3],rmj,wmj,r2inv,r6inv,scale,delscale[3];
			int ilist,jlist,numneigh,*firstneigh;
			int REBO_neighs_i,REBO_neighs_k;
			double delikS[3],delkjS[3],delkmS[3],delmjS[3];
			double rikS,rkjS,rkmS,rmjS,wikS,dwikS;
			double wkjS,dwkjS,wkmS,dwkmS,wmjS,dwmjS;
			double fpair1,fpair2,fpair3;

			// I-J interaction from full neighbor list
			// skip 1/2 of interactions since only consider each pair once

			evdwl = 0.0;

			double **x = atom->x;
			double **f = atom->f;
			int *tag = atom->tag;
			int *type = atom->type;
			int nlocal = atom->nlocal;
			int newton_pair = force->newton_pair;

			inum = list->inum;
			ilist = list->ilist;
			numneigh = list->numneigh;
			firstneigh = list->firstneigh;

			// loop over neighbors of my atoms

			for (ii = 0; ii < inum; ii++) {
			i = ilist[ii];
			itype = map[type[i]];
			atomi = i;
			jlist = firstneigh[i];
			jnum = numneigh[i];

			for (jj = 0; jj < jnum; jj++) {
			j = jlist[jj];
			atomj = j;
			if (tag[i] > tag[j]) continue;
			jtype = map[type[j]];

			delij[0] = x[i][0] - x[j][0];
			delij[1] = x[i][1] - x[j][1];
			delij[2] = x[i][2] - x[j][2];
			rijsq = delij[0]delij[0] + delij[1]delij[1] + delij[2]*delij[2];

			// if outside of LJ cutoff, skip
			// if outside of 4-path cutoff, best = 0.0, no need to test paths
			// if outside of 2-path cutoff but inside 4-path cutoff,
			// best = 0.0, test 3-,4-paths
			// if inside 2-path cutoff, best = wij, only test 3-,4-paths if best < 1

			if (rijsq >= cutljsq[itype][jtype]) continue;
			rij = sqrt(rijsq);
			if (rij >= cut3rebo) {
			best = 0.0;
			testpath = 0;
			} else if (rij >= rcmax[itype][jtype]) {
			best = 0.0;
			testpath = 1;
			} else {
			best = Sp(rij,rcmin[itype][jtype],rcmax[itype][jtype],dwij);
			npath = 2;
			if (best < 1.0) testpath = 1;
			else testpath = 0;
			}

			done = 0;
			if (testpath) {

			// test all 3-body paths = I-K-J
			// I-K interactions come from atom I's REBO neighbors
			// if wik > current best, compute wkj
			// if best = 1.0, done

			REBO_neighs_i = REBO_firstneigh[i];
			for (kk = 0; kk < REBO_numneigh[i] && done==0; kk++) {
			k = REBO_neighs_i[kk];
			if (k == j) continue;
			ktype = map[type[k]];

			delik[0] = x[i][0] - x[k][0];
			delik[1] = x[i][1] - x[k][1];
			delik[2] = x[i][2] - x[k][2];
			rsq = delik[0]delik[0] + delik[1]delik[1] + delik[2]*delik[2];
			if (rsq < rcmaxsq[itype][ktype]) {
			rik = sqrt(rsq);
			wik = Sp(rik,rcmin[itype][ktype],rcmax[itype][ktype],dwik);
			} else wik = 0.0;

			if (wik > best) {
			delkj[0] = x[k][0] - x[j][0];
			delkj[1] = x[k][1] - x[j][1];
			delkj[2] = x[k][2] - x[j][2];
			rsq = delkj[0]delkj[0] + delkj[1]delkj[1] + delkj[2]*delkj[2];
			if (rsq < rcmaxsq[ktype][jtype]) {
			rkj = sqrt(rsq);
			wkj = Sp(rkj,rcmin[ktype][jtype],rcmax[ktype][jtype],dwkj);
			if (wik*wkj > best) {
			best = wik*wkj;
			npath = 3;
			atomk = k;
			delikS[0] = delik[0];
			delikS[1] = delik[1];
			delikS[2] = delik[2];
			rikS = rik;
			wikS = wik;
			dwikS = dwik;
			delkjS[0] = delkj[0];
			delkjS[1] = delkj[1];
			delkjS[2] = delkj[2];
			rkjS = rkj;
			wkjS = wkj;
			dwkjS = dwkj;
			if (best == 1.0) {
			done = 1;
			break;
			}
			}
			}

			// test all 4-body paths = I-K-M-J
			// K-M interactions come from atom K's REBO neighbors
			// if wik*wkm > current best, compute wmj
			// if best = 1.0, done

			REBO_neighs_k = REBO_firstneigh[k];
			for (mm = 0; mm < REBO_numneigh[k] && done==0; mm++) {
			m = REBO_neighs_k[mm];
			if (m == i \|\| m == j) continue;
			mtype = map[type[m]];
			delkm[0] = x[k][0] - x[m][0];
			delkm[1] = x[k][1] - x[m][1];
			delkm[2] = x[k][2] - x[m][2];
			rsq = delkm[0]delkm[0] + delkm[1]delkm[1] + delkm[2]*delkm[2];
			if (rsq < rcmaxsq[ktype][mtype]) {
			rkm = sqrt(rsq);
			wkm = Sp(rkm,rcmin[ktype][mtype],rcmax[ktype][mtype],dwkm);
			} else wkm = 0.0;

			if (wik*wkm > best) {
			delmj[0] = x[m][0] - x[j][0];
			delmj[1] = x[m][1] - x[j][1];
			delmj[2] = x[m][2] - x[j][2];
			rsq = delmj[0]delmj[0] + delmj[1]delmj[1] +
			delmj[2]*delmj[2];
			if (rsq < rcmaxsq[mtype][jtype]) {
			rmj = sqrt(rsq);
			wmj = Sp(rmj,rcmin[mtype][jtype],rcmax[mtype][jtype],dwmj);
			if (wikwkmwmj > best) {
			best = wikwkmwmj;
			npath = 4;
			atomk = k;
			delikS[0] = delik[0];
			delikS[1] = delik[1];
			delikS[2] = delik[2];
			rikS = rik;
			wikS = wik;
			dwikS = dwik;
			atomm = m;
			delkmS[0] = delkm[0];
			delkmS[1] = delkm[1];
			delkmS[2] = delkm[2];
			rkmS = rkm;
			wkmS = wkm;
			dwkmS = dwkm;
			delmjS[0] = delmj[0];
			delmjS[1] = delmj[1];
			delmjS[2] = delmj[2];
			rmjS = rmj;
			wmjS = wmj;
			dwmjS = dwmj;
			if (best == 1.0) {
			done = 1;
			break;
			}
			}
			}
			}
			}
			}
			}
			}

			cij = 1.0 - best;
			if (cij == 0.0) continue;

			// compute LJ forces and energy

			r2inv = 1.0/rijsq;
			r6inv = r2invr2invr2inv;
			VLJ = r6inv(lj3[itype][jtype]r6inv-lj4[itype][jtype]);
			dVLJ = -r6inv * (lj1[itype][jtype]*r6inv - lj2[itype][jtype]) / rij;

			Str = Sp2(rij,rcLJmin[itype][jtype],rcLJmax[itype][jtype],dStr);
			VA = StrcijVLJ;
			if (Str > 0.0) {
			scale = rcmin[itype][jtype] / rij;
			delscale[0] = scale * delij[0];
			delscale[1] = scale * delij[1];
			delscale[2] = scale * delij[2];
			Stb = bondorderLJ(i,j,delscale,rcmin[itype][jtype],VA,delij,rij,f);
			} else Stb = 0.0;

			fpair = -(dStr * (StbcijVLJ - cij*VLJ) +
			dVLJ * (StrStbcij + cij - Str*cij)) / rij;

			f[i][0] += delij[0]*fpair;
			f[i][1] += delij[1]*fpair;
			f[i][2] += delij[2]*fpair;
			f[j][0] -= delij[0]*fpair;
			f[j][1] -= delij[1]*fpair;
			f[j][2] -= delij[2]*fpair;

			if (eflag) evdwl = VAStb + (1.0-Str)cij*VLJ;
			if (evflag) ev_tally(i,j,nlocal,newton_pair,
			evdwl,0.0,fpair,delij[0],delij[1],delij[2]);

			if (cij < 1.0) {
			dC = StrStbVLJ + (1.0-Str)*VLJ;
			if (npath == 2) {
			fpair = dC*dwij / rij;
			f[atomi][0] += delij[0]*fpair;
			f[atomi][1] += delij[1]*fpair;
			f[atomi][2] += delij[2]*fpair;
			f[atomj][0] -= delij[0]*fpair;
			f[atomj][1] -= delij[1]*fpair;
			f[atomj][2] -= delij[2]*fpair;
			if (vflag_atom) ev_tally(atomi,atomj,nlocal,newton_pair,
			0.0,0.0,fpair,delij[0],delij[1],delij[2]);
			} else if (npath == 3) {
			fpair1 = dCdwikSwkjS / rikS;
			f[atomi][0] += delikS[0]*fpair1;
			f[atomi][1] += delikS[1]*fpair1;
			f[atomi][2] += delikS[2]*fpair1;
			f[atomk][0] -= delikS[0]*fpair1;
			f[atomk][1] -= delikS[1]*fpair1;
			f[atomk][2] -= delikS[2]*fpair1;
			fpair2 = dCwikSdwkjS / rkjS;
			f[atomk][0] += delkjS[0]*fpair2;
			f[atomk][1] += delkjS[1]*fpair2;
			f[atomk][2] += delkjS[2]*fpair2;
			f[atomj][0] -= delkjS[0]*fpair2;
			f[atomj][1] -= delkjS[1]*fpair2;
			f[atomj][2] -= delkjS[2]*fpair2;
			if (vflag_atom)
			v_tally3(atomi,atomj,atomk,fpair1,fpair2,delikS,delkjS);
			} else {
			fpair1 = dCdwikSwkmS*wmjS / rikS;
			f[atomi][0] += delikS[0]*fpair1;
			f[atomi][1] += delikS[1]*fpair1;
			f[atomi][2] += delikS[2]*fpair1;
			f[atomk][0] -= delikS[0]*fpair1;
			f[atomk][1] -= delikS[1]*fpair1;
			f[atomk][2] -= delikS[2]*fpair1;
			fpair2 = dCwikSdwkmS*wmjS / rkmS;
			f[atomk][0] += delkmS[0]*fpair2;
			f[atomk][1] += delkmS[1]*fpair2;
			f[atomk][2] += delkmS[2]*fpair2;
			f[atomm][0] -= delkmS[0]*fpair2;
			f[atomm][1] -= delkmS[1]*fpair2;
			f[atomm][2] -= delkmS[2]*fpair2;
			fpair3 = dCwikSwkmS*dwmjS / rmjS;
			f[atomm][0] += delmjS[0]*fpair3;
			f[atomm][1] += delmjS[1]*fpair3;
			f[atomm][2] += delmjS[2]*fpair3;
			f[atomj][0] -= delmjS[0]*fpair3;
			f[atomj][1] -= delmjS[1]*fpair3;
			f[atomj][2] -= delmjS[2]*fpair3;
			if (vflag_atom)
			v_tally4(atomi,atomj,atomk,atomm,
			fpair1,fpair2,fpair3,delikS,delkmS,delmjS);
			}
			}
			}
			}
			}

			/* ----------------------------------------------------------------------
			Torsional forces and energy
			------------------------------------------------------------------------- */

			void PairAIREBO::TORSION(int eflag, int vflag)
			{
			int i,j,k,l;
			double evdwl,fpair;
			double cos321;
			double w21,dw21,cos234,w34,dw34;
			double cross321[3],cross321mag,cross234[3],cross234mag;
			double w23,dw23,cw2,ekijl,Ec;
			double cw,cwnum,cwnom;
			double rij,rij2,rik,rjl,tspjik,dtsjik,tspijl,dtsijl,costmp,fcpc;
			double sin321,sin234,rjk2,rik2,ril2,rjl2;
			double rjk,ril;
			double Vtors;
			double dndij[3],tmpvec[3],dndik[3],dndjl[3];
			double dcidij,dcidik,dcidjk,dcjdji,dcjdjl,dcjdil;
			double dsidij,dsidik,dsidjk,dsjdji,dsjdjl,dsjdil;
			double dxidij,dxidik,dxidjk,dxjdji,dxjdjl,dxjdil;
			double ddndij,ddndik,ddndjk,ddndjl,ddndil,dcwddn,dcwdn,dvpdcw,Ftmp[3];
			double del32[3],rsq,r32,del23[3],del21[3],r21;
			double deljk[3],del34[3],delil[3],r23,r34;
			double fi[3],fj[3],fk[3],fl[3];
			int itype,jtype,ktype,ltype,kk,ll,jj;
			int REBO_neighs_i,REBO_neighs_j;

			evdwl = 0.0;

			double **x = atom->x;
			double **f = atom->f;
			int *type = atom->type;
			int *tag = atom->tag;
			int nlocal = atom->nlocal;

			for (i = 0; i < nlocal; i++) {
			itype = map[type[i]];
			if (itype != 0) continue;
			REBO_neighs_i = REBO_firstneigh[i];

			for (jj = 0; jj < REBO_numneigh[i]; jj++) {
			j = REBO_neighs_i[jj];
			if (tag[i] > tag[j]) continue;
			jtype = map[type[j]];
			if (jtype != 0) continue;
			del32[0] = x[j][0]-x[i][0];
			del32[1] = x[j][1]-x[i][1];
			del32[2] = x[j][2]-x[i][2];
			rsq = del32[0]del32[0] + del32[1]del32[1] + del32[2]*del32[2];
			r32 = sqrt(rsq);
			del23[0] = -del32[0];
			del23[1] = -del32[1];
			del23[2] = -del32[2];
			r23 = r32;
			w23 = Sp(r23,rcmin[itype][jtype],rcmax[itype][jtype],dw23);

			for (kk = 0; kk < REBO_numneigh[i]; kk++) {
			k = REBO_neighs_i[kk];
			ktype = map[type[k]];
			if (k == j) continue;
			del21[0] = x[i][0]-x[k][0];
			del21[1] = x[i][1]-x[k][1];
			del21[2] = x[i][2]-x[k][2];
			rsq = del21[0]del21[0] + del21[1]del21[1] + del21[2]*del21[2];
			r21 = sqrt(rsq);
			cos321 = - ((del21[0]del32[0]) + (del21[1]del32[1]) +
			(del21[2]del32[2])) / (r21r32);
			cos321 = MIN(cos321,1.0);
			cos321 = MAX(cos321,-1.0);
			sin321 = sqrt(1.0 - cos321*cos321);
			if (sin321 < TOL) continue;

			deljk[0] = del21[0]-del23[0];
			deljk[1] = del21[1]-del23[1];
			deljk[2] = del21[2]-del23[2];
			rjk2 = deljk[0]deljk[0] + deljk[1]deljk[1] + deljk[2]*deljk[2];
			rjk=sqrt(rjk2);
			rik2 = r21*r21;
			w21 = Sp(r21,rcmin[itype][ktype],rcmax[itype][ktype],dw21);

			rij = r32;
			rik = r21;
			rij2 = r32*r32;
			rik2 = r21*r21;
			costmp = 0.5*(rij2+rik2-rjk2)/rij/rik;
			tspjik = Sp2(costmp,thmin,thmax,dtsjik);
			dtsjik = -dtsjik;

			REBO_neighs_j = REBO_firstneigh[j];
			for (ll = 0; ll < REBO_numneigh[j]; ll++) {
			l = REBO_neighs_j[ll];
			ltype = map[type[l]];
			if (l == i \|\| l == k) continue;
			del34[0] = x[j][0]-x[l][0];
			del34[1] = x[j][1]-x[l][1];
			del34[2] = x[j][2]-x[l][2];
			rsq = del34[0]del34[0] + del34[1]del34[1] + del34[2]*del34[2];
			r34 = sqrt(rsq);
			cos234 = (del32[0]del34[0] + del32[1]del34[1] +
			del32[2]del34[2]) / (r32r34);
			cos234 = MIN(cos234,1.0);
			cos234 = MAX(cos234,-1.0);
			sin234 = sqrt(1.0 - cos234*cos234);
			if (sin234 < TOL) continue;
			w34 = Sp(r34,rcmin[jtype][ltype],rcmax[jtype][ltype],dw34);
			delil[0] = del23[0] + del34[0];
			delil[1] = del23[1] + del34[1];
			delil[2] = del23[2] + del34[2];
			ril2 = delil[0]delil[0] + delil[1]delil[1] + delil[2]*delil[2];
			ril=sqrt(ril2);
			rjl2 = r34*r34;

			rjl = r34;
			rjl2 = r34*r34;
			costmp = 0.5*(rij2+rjl2-ril2)/rij/rjl;
			tspijl = Sp2(costmp,thmin,thmax,dtsijl);
			dtsijl = -dtsijl; //need minus sign
			cross321[0] = (del32[1]del21[2])-(del32[2]del21[1]);
			cross321[1] = (del32[2]del21[0])-(del32[0]del21[2]);
			cross321[2] = (del32[0]del21[1])-(del32[1]del21[0]);
			cross321mag = sqrt(cross321[0]*cross321[0]+
			cross321[1]*cross321[1]+
			cross321[2]*cross321[2]);
			cross234[0] = (del23[1]del34[2])-(del23[2]del34[1]);
			cross234[1] = (del23[2]del34[0])-(del23[0]del34[2]);
			cross234[2] = (del23[0]del34[1])-(del23[1]del34[0]);
			cross234mag = sqrt(cross234[0]*cross234[0]+
			cross234[1]*cross234[1]+
			cross234[2]*cross234[2]);
			cwnum = (cross321[0]*cross234[0]) +
			(cross321[1]cross234[1])+(cross321[2]cross234[2]);
			cwnom = r21r34r32r32sin321*sin234;
			cw = cwnum/cwnom;

			cw2 = (.5*(1.0-cw));
			ekijl = epsilonT[ktype][ltype];
			Ec = 256.0*ekijl/405.0;
			Vtors = (Ec*(pow(cw2,5.0)))-(ekijl/10.0);

			if (eflag) evdwl = Vtorsw21w23w34(1.0-tspjik)*(1.0-tspijl);

			dndij[0] = (cross234[1]del21[2])-(cross234[2]del21[1]);
			dndij[1] = (cross234[2]del21[0])-(cross234[0]del21[2]);
			dndij[2] = (cross234[0]del21[1])-(cross234[1]del21[0]);

			tmpvec[0] = (del34[1]cross321[2])-(del34[2]cross321[1]);
			tmpvec[1] = (del34[2]cross321[0])-(del34[0]cross321[2]);
			tmpvec[2] = (del34[0]cross321[1])-(del34[1]cross321[0]);

			dndij[0] = dndij[0]+tmpvec[0];
			dndij[1] = dndij[1]+tmpvec[1];
			dndij[2] = dndij[2]+tmpvec[2];

			dndik[0] = (del23[1]cross234[2])-(del23[2]cross234[1]);
			dndik[1] = (del23[2]cross234[0])-(del23[0]cross234[2]);
			dndik[2] = (del23[0]cross234[1])-(del23[1]cross234[0]);

			dndjl[0] = (cross321[1]del23[2])-(cross321[2]del23[1]);
			dndjl[1] = (cross321[2]del23[0])-(cross321[0]del23[2]);
			dndjl[2] = (cross321[0]del23[1])-(cross321[1]del23[0]);

			dcidij = ((r23r23)-(r21r21)+(rjkrjk))/(2.0r23r23r21);
			dcidik = ((r21r21)-(r23r23)+(rjkrjk))/(2.0r23r21r21);
			dcidjk = (-rjk)/(r23*r21);
			dcjdji = ((r23r23)-(r34r34)+(rilril))/(2.0r23r23r34);
			dcjdjl = ((r34r34)-(r23r23)+(rilril))/(2.0r23r34r34);
			dcjdil = (-ril)/(r23*r34);

			dsidij = (-cos321/sin321)*dcidij;
			dsidik = (-cos321/sin321)*dcidik;
			dsidjk = (-cos321/sin321)*dcidjk;

			dsjdji = (-cos234/sin234)*dcjdji;
			dsjdjl = (-cos234/sin234)*dcjdjl;
			dsjdil = (-cos234/sin234)*dcjdil;

			dxidij = (r21sin321)+(r23r21*dsidij);
			dxidik = (r23sin321)+(r23r21*dsidik);
			dxidjk = (r23r21dsidjk);

			dxjdji = (r34sin234)+(r23r34*dsjdji);
			dxjdjl = (r23sin234)+(r23r34*dsjdjl);
			dxjdil = (r23r34dsjdil);

			ddndij = (dxidijcross234mag)+(cross321magdxjdji);
			ddndik = dxidik*cross234mag;
			ddndjk = dxidjk*cross234mag;
			ddndjl = cross321mag*dxjdjl;
			ddndil = cross321mag*dxjdil;
			dcwddn = -cwnum/(cwnom*cwnom);
			dcwdn = 1.0/cwnom;
			dvpdcw = (-1.0)Ec(-.5)5.0pow(cw2,4.0) *
			w23w21w34(1.0-tspjik)(1.0-tspijl);

			Ftmp[0] = dvpdcw((dcwdndndij[0])+(dcwddnddndijdel23[0]/r23));
			Ftmp[1] = dvpdcw((dcwdndndij[1])+(dcwddnddndijdel23[1]/r23));
			Ftmp[2] = dvpdcw((dcwdndndij[2])+(dcwddnddndijdel23[2]/r23));
			fi[0] = Ftmp[0];
			fi[1] = Ftmp[1];
			fi[2] = Ftmp[2];
			fj[0] = -Ftmp[0];
			fj[1] = -Ftmp[1];
			fj[2] = -Ftmp[2];

			Ftmp[0] = dvpdcw((dcwdndndik[0])+(dcwddnddndikdel21[0]/r21));
			Ftmp[1] = dvpdcw((dcwdndndik[1])+(dcwddnddndikdel21[1]/r21));
			Ftmp[2] = dvpdcw((dcwdndndik[2])+(dcwddnddndikdel21[2]/r21));
			fi[0] += Ftmp[0];
			fi[1] += Ftmp[1];
			fi[2] += Ftmp[2];
			fk[0] = -Ftmp[0];
			fk[1] = -Ftmp[1];
			fk[2] = -Ftmp[2];

			Ftmp[0] = (dvpdcwdcwddnddndjk*deljk[0])/rjk;
			Ftmp[1] = (dvpdcwdcwddnddndjk*deljk[1])/rjk;
			Ftmp[2] = (dvpdcwdcwddnddndjk*deljk[2])/rjk;
			fj[0] += Ftmp[0];
			fj[1] += Ftmp[1];
			fj[2] += Ftmp[2];
			fk[0] -= Ftmp[0];
			fk[1] -= Ftmp[1];
			fk[2] -= Ftmp[2];

			Ftmp[0] = dvpdcw((dcwdndndjl[0])+(dcwddnddndjldel34[0]/r34));
			Ftmp[1] = dvpdcw((dcwdndndjl[1])+(dcwddnddndjldel34[1]/r34));
			Ftmp[2] = dvpdcw((dcwdndndjl[2])+(dcwddnddndjldel34[2]/r34));
			fj[0] += Ftmp[0];
			fj[1] += Ftmp[1];
			fj[2] += Ftmp[2];
			fl[0] = -Ftmp[0];
			fl[1] = -Ftmp[1];
			fl[2] = -Ftmp[2];

			Ftmp[0] = (dvpdcwdcwddnddndil*delil[0])/ril;
			Ftmp[1] = (dvpdcwdcwddnddndil*delil[1])/ril;
			Ftmp[2] = (dvpdcwdcwddnddndil*delil[2])/ril;
			fi[0] += Ftmp[0];
			fi[1] += Ftmp[1];
			fi[2] += Ftmp[2];
			fl[0] -= Ftmp[0];
			fl[1] -= Ftmp[1];
			fl[2] -= Ftmp[2];

			// coordination forces

			fpair = Vtorsdw21w23w34(1.0-tspjik)*(1.0-tspijl) / r21;
			fi[0] -= del21[0]*fpair;
			fi[1] -= del21[1]*fpair;
			fi[2] -= del21[2]*fpair;
			fk[0] += del21[0]*fpair;
			fk[1] += del21[1]*fpair;
			fk[2] += del21[2]*fpair;

			fpair = Vtorsw21dw23w34(1.0-tspjik)*(1.0-tspijl) / r23;
			fi[0] -= del23[0]*fpair;
			fi[1] -= del23[1]*fpair;
			fi[2] -= del23[2]*fpair;
			fj[0] += del23[0]*fpair;
			fj[1] += del23[1]*fpair;
			fj[2] += del23[2]*fpair;

			fpair = Vtorsw21w23dw34(1.0-tspjik)*(1.0-tspijl) / r34;
			fj[0] -= del34[0]*fpair;
			fj[1] -= del34[1]*fpair;
			fj[2] -= del34[2]*fpair;
			fl[0] += del34[0]*fpair;
			fl[1] += del34[1]*fpair;
			fl[2] += del34[2]*fpair;

			// additional cut off function forces

			fcpc = -Vtorsw21w23w34dtsjik*(1.0-tspijl);
			fpair = fcpc*dcidij/rij;
			fi[0] += fpair*del23[0];
			fi[1] += fpair*del23[1];
			fi[2] += fpair*del23[2];
			fj[0] -= fpair*del23[0];
			fj[1] -= fpair*del23[1];
			fj[2] -= fpair*del23[2];

			fpair = fcpc*dcidik/rik;
			fi[0] += fpair*del21[0];
			fi[1] += fpair*del21[1];
			fi[2] += fpair*del21[2];
			fk[0] -= fpair*del21[0];
			fk[1] -= fpair*del21[1];
			fk[2] -= fpair*del21[2];

			fpair = fcpc*dcidjk/rjk;
			fj[0] += fpair*deljk[0];
			fj[1] += fpair*deljk[1];
			fj[2] += fpair*deljk[2];
			fk[0] -= fpair*deljk[0];
			fk[1] -= fpair*deljk[1];
			fk[2] -= fpair*deljk[2];

			fcpc = -Vtorsw21w23w34(1.0-tspjik)*dtsijl;
			fpair = fcpc*dcjdji/rij;
			fi[0] += fpair*del23[0];
			fi[1] += fpair*del23[1];
			fi[2] += fpair*del23[2];
			fj[0] -= fpair*del23[0];
			fj[1] -= fpair*del23[1];
			fj[2] -= fpair*del23[2];

			fpair = fcpc*dcjdjl/rjl;
			fj[0] += fpair*del34[0];
			fj[1] += fpair*del34[1];
			fj[2] += fpair*del34[2];
			fl[0] -= fpair*del34[0];
			fl[1] -= fpair*del34[1];
			fl[2] -= fpair*del34[2];

			fpair = fcpc*dcjdil/ril;
			fi[0] += fpair*delil[0];
			fi[1] += fpair*delil[1];
			fi[2] += fpair*delil[2];
			fl[0] -= fpair*delil[0];
			fl[1] -= fpair*delil[1];
			fl[2] -= fpair*delil[2];

			// sum per-atom forces into atom force array

			f[i][0] += fi[0]; f[i][1] += fi[1]; f[i][2] += fi[2];
			f[j][0] += fj[0]; f[j][1] += fj[1]; f[j][2] += fj[2];
			f[k][0] += fk[0]; f[k][1] += fk[1]; f[k][2] += fk[2];
			f[l][0] += fl[0]; f[l][1] += fl[1]; f[l][2] += fl[2];

			//if (evflag) ev_tally4(i,j,k,l,fi,fj,fk,fl);
			}
			}
			}
			}
			}

			// ----------------------------------------------------------------------
			// S'(t) and S(t) cutoff functions
			// ----------------------------------------------------------------------

			/* ----------------------------------------------------------------------
			cutoff function Sprime
			return cutoff and dX = derivative
			------------------------------------------------------------------------- */

			double PairAIREBO::Sp(double Xij, double Xmin, double Xmax, double &dX)
			{
			double cutoff;

			double t = (Xij-Xmin) / (Xmax-Xmin);
			if (t <= 0.0) {
			cutoff = 1.0;
			dX = 0.0;
			}
			else if (t >= 1.0) {
			cutoff = 0.0;
			dX = 0.0;
			}
			else {
			cutoff = 0.5 * (1.0+cos(PI*t));
			dX = (-0.5PIsin(PI*t)) / (Xmax-Xmin);
			}
			return cutoff;
			}

			/* ----------------------------------------------------------------------
			LJ cutoff function Sp2
			return cutoff and dX = derivative
			------------------------------------------------------------------------- */

			double PairAIREBO::Sp2(double Xij, double Xmin, double Xmax, double &dX)
			{
			double cutoff;

			double t = (Xij-Xmin) / (Xmax-Xmin);
			if (t <= 0.0) {
			cutoff = 1.0;
			dX = 0.0;
			}
			if (t >= 1.0) {
			cutoff = 0.0;
			dX = 0.0;
			}
			if (t>0.0 && t<1.0) {
			cutoff = (1.0-(tt(3.0-2.0*t)));
			dX = 6.0(tt-t) / (Xmax-Xmin);
			}
			return cutoff;
			}

			/* ----------------------------------------------------------------------
			Bij function
			------------------------------------------------------------------------- */

			double PairAIREBO::bondorder(int i, int j, double rij[3],
			double rijmag, double VA, double **f)
			{
			int atomi,atomj,k,n,l,atomk,atoml,atomn,atom1,atom2,atom3,atom4;
			int itype,jtype,ktype,ltype,ntype;
			double rik[3], rjl[3], rkn[3],rknmag,dNki,dwjl,bij;
			double NijC,NijH,NjiC,NjiH,wik,dwik,dwkn,wjl;
			double rikmag,rjlmag,cosjik,cosijl,g,tmp2,tmp3;
			double Etmp,pij,tmp,wij,dwij,NconjtmpI,NconjtmpJ,Nki,Nlj,dS;
			double lamdajik,lamdaijl,dgdc,dgdN,pji,Nijconj,piRC;
			double dcosjikdri[3],dcosijldri[3],dcosjikdrk[3];
			double dN2[2],dN3[3];
			double dcosjikdrj[3],dcosijldrj[3],dcosijldrl[3];
			double Tij;
			double r32[3],r32mag,cos321;
			double dNlj;
			double om1234,rln[3];
			double rlnmag,dwln,r23[3],r23mag,r21[3],r21mag;
			double w21,dw21,r34[3],r34mag,cos234,w34,dw34;
			double cross321[3],cross234[3],prefactor,SpN;
			double fcijpc,fcikpc,fcjlpc,fcjkpc,fcilpc;
			double dt2dik[3],dt2djl[3],dt2dij[3],aa,aaa1,aaa2,at2,cw,cwnum,cwnom;
			double sin321,sin234,rr,rijrik,rijrjl,rjk2,rik2,ril2,rjl2;
			double dctik,dctjk,dctjl,dctij,dctji,dctil,rik2i,rjl2i,sink2i,sinl2i;
			double rjk[3],ril[3],dt1dik,dt1djk,dt1djl,dt1dil,dt1dij;
			double F23[3],F12[3],F34[3],F31[3],F24[3];
			double dcut321,PijS,PjiS;
			double rij2,tspjik,dtsjik,tspijl,dtsijl,costmp;
			int REBO_neighs,REBO_neighs_i,REBO_neighs_j,REBO_neighs_k,*REBO_neighs_l;

			double **x = atom->x;
			int *type = atom->type;

			atomi = i;
			atomj = j;
			itype = map[type[i]];
			jtype = map[type[j]];
			wij = Sp(rijmag,rcmin[itype][jtype],rcmax[itype][jtype],dwij);
			NijC = nC[i]-(wij*kronecker(jtype,0));
			NijH = nH[i]-(wij*kronecker(jtype,1));
			NjiC = nC[j]-(wij*kronecker(itype,0));
			NjiH = nH[j]-(wij*kronecker(itype,1));
			bij = 0.0;
			tmp = 0.0;
			tmp2 = 0.0;
			tmp3 = 0.0;
			dgdc = 0.0;
			dgdN = 0.0;
			NconjtmpI = 0.0;
			NconjtmpJ = 0.0;
			Etmp = 0.0;

			REBO_neighs = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs[k];
			if (atomk != atomj) {
			ktype = map[type[atomk]];
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt((rik[0]rik[0])+(rik[1]rik[1])+(rik[2]*rik[2]));
			lamdajik = 4.0kronecker(itype,1)
			((rho[ktype][1]-rikmag)-(rho[jtype][1]-rijmag));
			wik = Sp(rikmag,rcmin[itype][ktype],rcmax[itype][ktype],dS);
			Nki = nC[atomk]-(wik*kronecker(itype,0))+nH[atomk] -
			(wik*kronecker(itype,1));
			cosjik = ((rij[0]rik[0])+(rij[1]rik[1])+(rij[2]*rik[2])) /
			(rijmag*rikmag);
			cosjik = MIN(cosjik,1.0);
			cosjik = MAX(cosjik,-1.0);

			// evaluate splines g and derivatives dg

			g = gSpline(cosjik,(NijC+NijH),itype,&dgdc,&dgdN);
			Etmp = Etmp+(wikgexp(lamdajik));
			tmp3 = tmp3+(wikdgdNexp(lamdajik));
			NconjtmpI = NconjtmpI+(kronecker(ktype,0)wikSp(Nki,Nmin,Nmax,dS));
			}
			}

			PijS = 0.0;
			dN2[0] = 0.0;
			dN2[1] = 0.0;
			PijS = PijSpline(NijC,NijH,itype,jtype,dN2);
			pij = pow(1.0+Etmp+PijS,-0.5);
			tmp = -0.5*pow(pij,3.0);

			// pij forces

			REBO_neighs = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs[k];
			if (atomk != atomj) {
			ktype = map[type[atomk]];
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt((rik[0]rik[0])+(rik[1]rik[1])+(rik[2]*rik[2]));
			lamdajik = 4.0kronecker(itype,1)
			((rho[ktype][1]-rikmag)-(rho[jtype][1]-rijmag));
			wik = Sp(rikmag,rcmin[itype][ktype],rcmax[itype][ktype],dwik);
			cosjik = (rij[0]rik[0] + rij[1]rik[1] + rij[2]*rik[2]) /
			(rijmag*rikmag);
			cosjik = MIN(cosjik,1.0);
			cosjik = MAX(cosjik,-1.0);

			dcosjikdri[0] = ((rij[0]+rik[0])/(rijmag*rikmag)) -
			(cosjik((rij[0]/(rijmagrijmag))+(rik[0]/(rikmag*rikmag))));
			dcosjikdri[1] = ((rij[1]+rik[1])/(rijmag*rikmag)) -
			(cosjik((rij[1]/(rijmagrijmag))+(rik[1]/(rikmag*rikmag))));
			dcosjikdri[2] = ((rij[2]+rik[2])/(rijmag*rikmag)) -
			(cosjik((rij[2]/(rijmagrijmag))+(rik[2]/(rikmag*rikmag))));
			dcosjikdrk[0] = (-rij[0]/(rijmag*rikmag)) +
			(cosjik(rik[0]/(rikmagrikmag)));
			dcosjikdrk[1] = (-rij[1]/(rijmag*rikmag)) +
			(cosjik(rik[1]/(rikmagrikmag)));
			dcosjikdrk[2] = (-rij[2]/(rijmag*rikmag)) +
			(cosjik(rik[2]/(rikmagrikmag)));
			dcosjikdrj[0] = (-rik[0]/(rijmag*rikmag)) +
			(cosjik(rij[0]/(rijmagrijmag)));
			dcosjikdrj[1] = (-rik[1]/(rijmag*rikmag)) +
			(cosjik(rij[1]/(rijmagrijmag)));
			dcosjikdrj[2] = (-rik[2]/(rijmag*rikmag)) +
			(cosjik(rij[2]/(rijmagrijmag)));

			g = gSpline(cosjik,(NijC+NijH),itype,&dgdc,&dgdN);
			tmp2 = VA.5(tmpwikdgdc*exp(lamdajik));
			f[atomj][0] -= tmp2*dcosjikdrj[0];
			f[atomj][1] -= tmp2*dcosjikdrj[1];
			f[atomj][2] -= tmp2*dcosjikdrj[2];
			f[atomi][0] -= tmp2*dcosjikdri[0];
			f[atomi][1] -= tmp2*dcosjikdri[1];
			f[atomi][2] -= tmp2*dcosjikdri[2];
			f[atomk][0] -= tmp2*dcosjikdrk[0];
			f[atomk][1] -= tmp2*dcosjikdrk[1];
			f[atomk][2] -= tmp2*dcosjikdrk[2];

			tmp2 = VA.5(tmpwikgexp(lamdajik)4.0*kronecker(itype,1));
			f[atomj][0] -= tmp2*(-rij[0]/rijmag);
			f[atomj][1] -= tmp2*(-rij[1]/rijmag);
			f[atomj][2] -= tmp2*(-rij[2]/rijmag);
			f[atomi][0] -= tmp2*((-rik[0]/rikmag)+(rij[0]/rijmag));
			f[atomi][1] -= tmp2*((-rik[1]/rikmag)+(rij[1]/rijmag));
			f[atomi][2] -= tmp2*((-rik[2]/rikmag)+(rij[2]/rijmag));
			f[atomk][0] -= tmp2*(rik[0]/rikmag);
			f[atomk][1] -= tmp2*(rik[1]/rikmag);
			f[atomk][2] -= tmp2*(rik[2]/rikmag);

			// coordination forces

			// dwik forces

			tmp2 = VA.5(tmpdwikg*exp(lamdajik))/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			// PIJ forces

			tmp2 = VA.5(tmpdN2[ktype]dwik)/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			// dgdN forces

			tmp2 = VA.5(tmptmp3dwik)/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];
			}
			}

			tmp = 0.0;
			tmp2 = 0.0;
			tmp3 = 0.0;
			Etmp = 0.0;

			REBO_neighs = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs[l];
			if (atoml != atomi) {
			ltype = map[type[atoml]];
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt((rjl[0]rjl[0])+(rjl[1]rjl[1])+(rjl[2]*rjl[2]));
			lamdaijl = 4.0kronecker(jtype,1)
			((rho[ltype][1]-rjlmag)-(rho[itype][1]-rijmag));
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmax[jtype][ltype],dS);
			Nlj = nC[atoml]-(wjl*kronecker(jtype,0)) +
			nH[atoml]-(wjl*kronecker(jtype,1));
			cosijl = -1.0((rij[0]rjl[0])+(rij[1]rjl[1])+(rij[2]rjl[2])) /
			(rijmag*rjlmag);
			cosijl = MIN(cosijl,1.0);
			cosijl = MAX(cosijl,-1.0);

			// evaluate splines g and derivatives dg

			g = gSpline(cosijl,NjiC+NjiH,jtype,&dgdc,&dgdN);
			Etmp = Etmp+(wjlgexp(lamdaijl));
			tmp3 = tmp3+(wjldgdNexp(lamdaijl));
			NconjtmpJ = NconjtmpJ+(kronecker(ltype,0)wjlSp(Nlj,Nmin,Nmax,dS));
			}
			}

			PjiS = 0.0;
			dN2[0] = 0.0;
			dN2[1] = 0.0;
			PjiS = PijSpline(NjiC,NjiH,jtype,itype,dN2);
			pji = pow(1.0+Etmp+PjiS,-0.5);
			tmp = -0.5*pow(pji,3.0);

			REBO_neighs = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs[l];
			if (atoml != atomi) {
			ltype = map[type[atoml]];
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt((rjl[0]rjl[0])+(rjl[1]rjl[1])+(rjl[2]*rjl[2]));
			lamdaijl = 4.0kronecker(jtype,1)
			((rho[ltype][1]-rjlmag)-(rho[itype][1]-rijmag));
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmax[jtype][ltype],dwjl);
			cosijl = (-1.0((rij[0]rjl[0])+(rij[1]rjl[1])+(rij[2]rjl[2]))) /
			(rijmag*rjlmag);
			cosijl = MIN(cosijl,1.0);
			cosijl = MAX(cosijl,-1.0);

			dcosijldri[0] = (-rjl[0]/(rijmag*rjlmag)) -
			(cosijlrij[0]/(rijmagrijmag));
			dcosijldri[1] = (-rjl[1]/(rijmag*rjlmag)) -
			(cosijlrij[1]/(rijmagrijmag));
			dcosijldri[2] = (-rjl[2]/(rijmag*rjlmag)) -
			(cosijlrij[2]/(rijmagrijmag));
			dcosijldrj[0] = ((-rij[0]+rjl[0])/(rijmag*rjlmag)) +
			(cosijl((rij[0]/pow(rijmag,2.0))-(rjl[0]/(rjlmagrjlmag))));
			dcosijldrj[1] = ((-rij[1]+rjl[1])/(rijmag*rjlmag)) +
			(cosijl((rij[1]/pow(rijmag,2.0))-(rjl[1]/(rjlmagrjlmag))));
			dcosijldrj[2] = ((-rij[2]+rjl[2])/(rijmag*rjlmag)) +
			(cosijl((rij[2]/pow(rijmag,2.0))-(rjl[2]/(rjlmagrjlmag))));
			dcosijldrl[0] = (rij[0]/(rijmagrjlmag))+(cosijlrjl[0]/(rjlmag*rjlmag));
			dcosijldrl[1] = (rij[1]/(rijmagrjlmag))+(cosijlrjl[1]/(rjlmag*rjlmag));
			dcosijldrl[2] = (rij[2]/(rijmagrjlmag))+(cosijlrjl[2]/(rjlmag*rjlmag));

			// evaluate splines g and derivatives dg

			g = gSpline(cosijl,NjiC+NjiH,jtype,&dgdc,&dgdN);
			tmp2 = VA.5(tmpwjldgdc*exp(lamdaijl));
			f[atomi][0] -= tmp2*dcosijldri[0];
			f[atomi][1] -= tmp2*dcosijldri[1];
			f[atomi][2] -= tmp2*dcosijldri[2];
			f[atomj][0] -= tmp2*dcosijldrj[0];
			f[atomj][1] -= tmp2*dcosijldrj[1];
			f[atomj][2] -= tmp2*dcosijldrj[2];
			f[atoml][0] -= tmp2*dcosijldrl[0];
			f[atoml][1] -= tmp2*dcosijldrl[1];
			f[atoml][2] -= tmp2*dcosijldrl[2];

			tmp2 = VA.5(tmpwjlgexp(lamdaijl)4.0*kronecker(jtype,1));
			f[atomi][0] -= tmp2*(rij[0]/rijmag);
			f[atomi][1] -= tmp2*(rij[1]/rijmag);
			f[atomi][2] -= tmp2*(rij[2]/rijmag);
			f[atomj][0] -= tmp2*((-rjl[0]/rjlmag)-(rij[0]/rijmag));
			f[atomj][1] -= tmp2*((-rjl[1]/rjlmag)-(rij[1]/rijmag));
			f[atomj][2] -= tmp2*((-rjl[2]/rjlmag)-(rij[2]/rijmag));
			f[atoml][0] -= tmp2*(rjl[0]/rjlmag);
			f[atoml][1] -= tmp2*(rjl[1]/rjlmag);
			f[atoml][2] -= tmp2*(rjl[2]/rjlmag);

			// coordination forces

			// dwik forces

			tmp2 = VA.5(tmpdwjlg*exp(lamdaijl))/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			// PIJ forces

			tmp2 = VA.5(tmpdN2[ltype]dwjl)/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			// dgdN forces

			tmp2 = VA.5(tmptmp3dwjl)/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];
			}
			}

			// evaluate Nij conj

			Nijconj = 1.0+(NconjtmpINconjtmpI)+(NconjtmpJNconjtmpJ);
			piRC = piRCSpline(NijC+NijH,NjiC+NjiH,Nijconj,itype,jtype,dN3);

			// piRC forces

			REBO_neighs_i = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs_i[k];
			if (atomk !=atomj) {
			ktype = map[type[atomk]];
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt((rik[0]rik[0])+(rik[1]rik[1])+(rik[2]*rik[2]));
			wik = Sp(rikmag,rcmin[itype][ktype],rcmax[itype][ktype],dwik);
			Nki = nC[atomk]-(wik*kronecker(itype,0))+nH[atomk] -
			(wik*kronecker(itype,1));
			SpN = Sp(Nki,Nmin,Nmax,dNki);

			tmp2 = VAdN3[0]dwik/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			tmp2 = VAdN3[2](2.0NconjtmpIdwik*SpN)/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			if (fabs(dNki) > TOL) {
			REBO_neighs_k = REBO_firstneigh[atomk];
			for (n = 0; n < REBO_numneigh[atomk]; n++) {
			atomn = REBO_neighs_k[n];
			if (atomn != atomi) {
			ntype = map[type[atomn]];
			rkn[0] = x[atomk][0]-x[atomn][0];
			rkn[1] = x[atomk][1]-x[atomn][1];
			rkn[2] = x[atomk][2]-x[atomn][2];
			rknmag = sqrt((rkn[0]rkn[0])+(rkn[1]rkn[1])+(rkn[2]*rkn[2]));
			Sp(rknmag,rcmin[ktype][ntype],rcmax[ktype][ntype],dwkn);

			tmp2 = VAdN3[2](2.0NconjtmpIwikdNkidwkn)/rknmag;
			f[atomk][0] -= tmp2*rkn[0];
			f[atomk][1] -= tmp2*rkn[1];
			f[atomk][2] -= tmp2*rkn[2];
			f[atomn][0] += tmp2*rkn[0];
			f[atomn][1] += tmp2*rkn[1];
			f[atomn][2] += tmp2*rkn[2];
			}
			}
			}
			}
			}

			// piRC forces

			REBO_neighs = REBO_firstneigh[atomj];
			for (l = 0; l < REBO_numneigh[atomj]; l++) {
			atoml = REBO_neighs[l];
			if (atoml !=atomi) {
			ltype = map[type[atoml]];
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt((rjl[0]rjl[0])+(rjl[1]rjl[1])+(rjl[2]*rjl[2]));
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmax[jtype][ltype],dwjl);
			Nlj = nC[atoml]-(wjl*kronecker(jtype,0))+nH[atoml] -
			(wjl*kronecker(jtype,1));
			SpN = Sp(Nlj,Nmin,Nmax,dNlj);

			tmp2 = VAdN3[1]dwjl/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			tmp2 = VAdN3[2](2.0NconjtmpJdwjl*SpN)/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			if (fabs(dNlj) > TOL) {
			REBO_neighs_l = REBO_firstneigh[atoml];
			for (n = 0; n < REBO_numneigh[atoml]; n++) {
			atomn = REBO_neighs_l[n];
			if (atomn != atomj) {
			ntype = map[type[atomn]];
			rln[0] = x[atoml][0]-x[atomn][0];
			rln[1] = x[atoml][1]-x[atomn][1];
			rln[2] = x[atoml][2]-x[atomn][2];
			rlnmag = sqrt((rln[0]rln[0])+(rln[1]rln[1])+(rln[2]*rln[2]));
			Sp(rlnmag,rcmin[ltype][ntype],rcmax[ltype][ntype],dwln);

			tmp2 = VAdN3[2](2.0NconjtmpJwjldNljdwln)/rlnmag;
			f[atoml][0] -= tmp2*rln[0];
			f[atoml][1] -= tmp2*rln[1];
			f[atoml][2] -= tmp2*rln[2];
			f[atomn][0] += tmp2*rln[0];
			f[atomn][1] += tmp2*rln[1];
			f[atomn][2] += tmp2*rln[2];
			}
			}
			}
			}
			}

			Tij = 0.0;
			dN3[0] = 0.0;
			dN3[1] = 0.0;
			dN3[2] = 0.0;
			if (itype == 0 && jtype == 0)
			Tij=TijSpline((NijC+NijH),(NjiC+NjiH),Nijconj,dN3);
			Etmp = 0.0;

			if (fabs(Tij) > TOL) {
			atom2 = atomi;
			atom3 = atomj;
			r32[0] = x[atom3][0]-x[atom2][0];
			r32[1] = x[atom3][1]-x[atom2][1];
			r32[2] = x[atom3][2]-x[atom2][2];
			r32mag = sqrt((r32[0]r32[0])+(r32[1]r32[1])+(r32[2]*r32[2]));
			r23[0] = -r32[0];
			r23[1] = -r32[1];
			r23[2] = -r32[2];
			r23mag = r32mag;
			REBO_neighs_i = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs_i[k];
			atom1 = atomk;
			ktype = map[type[atomk]];
			if (atomk != atomj) {
			r21[0] = x[atom2][0]-x[atom1][0];
			r21[1] = x[atom2][1]-x[atom1][1];
			r21[2] = x[atom2][2]-x[atom1][2];
			r21mag = sqrt(r21[0]r21[0] + r21[1]r21[1] + r21[2]*r21[2]);
			cos321 = -1.0((r21[0]r32[0])+(r21[1]r32[1])+(r21[2]r32[2])) /
			(r21mag*r32mag);
			cos321 = MIN(cos321,1.0);
			cos321 = MAX(cos321,-1.0);
			Sp2(cos321,thmin,thmax,dcut321);
			sin321 = sqrt(1.0 - cos321*cos321);
			sink2i = 1.0/(sin321*sin321);
			rik2i = 1.0/(r21mag*r21mag);
			if (sin321 != 0.0) {
			rr = (r23magr23mag)-(r21magr21mag);
			rjk[0] = r21[0]-r23[0];
			rjk[1] = r21[1]-r23[1];
			rjk[2] = r21[2]-r23[2];
			rjk2 = (rjk[0]rjk[0])+(rjk[1]rjk[1])+(rjk[2]*rjk[2]);
			rijrik = 2.0r23magr21mag;
			rik2 = r21mag*r21mag;
			dctik = (-rr+rjk2)/(rijrik*rik2);
			dctij = (rr+rjk2)/(rijrikr23magr23mag);
			dctjk = -2.0/rijrik;
			w21 = Sp(r21mag,rcmin[itype][ktype],rcmaxp[itype][ktype],dw21);
			rijmag = r32mag;
			rikmag = r21mag;
			rij2 = r32mag*r32mag;
			rik2 = r21mag*r21mag;
			costmp = 0.5*(rij2+rik2-rjk2)/rijmag/rikmag;
			tspjik = Sp2(costmp,thmin,thmax,dtsjik);
			dtsjik = -dtsjik;

			REBO_neighs_j = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs_j[l];
			atom4 = atoml;
			ltype = map[type[atoml]];
			if (!(atoml == atomi \|\| atoml == atomk)) {
			r34[0] = x[atom3][0]-x[atom4][0];
			r34[1] = x[atom3][1]-x[atom4][1];
			r34[2] = x[atom3][2]-x[atom4][2];
			r34mag = sqrt((r34[0]r34[0])+(r34[1]r34[1])+(r34[2]*r34[2]));
			cos234 = (r32[0]r34[0] + r32[1]r34[1] + r32[2]*r34[2]) /
			(r32mag*r34mag);
			cos234 = MIN(cos234,1.0);
			cos234 = MAX(cos234,-1.0);
			sin234 = sqrt(1.0 - cos234*cos234);
			sinl2i = 1.0/(sin234*sin234);
			rjl2i = 1.0/(r34mag*r34mag);

			if (sin234 != 0.0) {
			w34 = Sp(r34mag,rcmin[jtype][ltype],rcmaxp[jtype][ltype],dw34);
			rr = (r23magr23mag)-(r34magr34mag);
			ril[0] = r23[0]+r34[0];
			ril[1] = r23[1]+r34[1];
			ril[2] = r23[2]+r34[2];
			ril2 = (ril[0]ril[0])+(ril[1]ril[1])+(ril[2]*ril[2]);
			rijrjl = 2.0r23magr34mag;
			rjl2 = r34mag*r34mag;
			dctjl = (-rr+ril2)/(rijrjl*rjl2);
			dctji = (rr+ril2)/(rijrjlr23magr23mag);
			dctil = -2.0/rijrjl;
			rjlmag = r34mag;
			rjl2 = r34mag*r34mag;
			costmp = 0.5*(rij2+rjl2-ril2)/rijmag/rjlmag;
			tspijl = Sp2(costmp,thmin,thmax,dtsijl);
			dtsijl = -dtsijl;
			prefactor = VA*Tij;

			cross321[0] = (r32[1]r21[2])-(r32[2]r21[1]);
			cross321[1] = (r32[2]r21[0])-(r32[0]r21[2]);
			cross321[2] = (r32[0]r21[1])-(r32[1]r21[0]);
			cross234[0] = (r23[1]r34[2])-(r23[2]r34[1]);
			cross234[1] = (r23[2]r34[0])-(r23[0]r34[2]);
			cross234[2] = (r23[0]r34[1])-(r23[1]r34[0]);

			cwnum = (cross321[0]*cross234[0]) +
			(cross321[1]cross234[1]) + (cross321[2]cross234[2]);
			cwnom = r21magr34magr23magr23magsin321*sin234;
			om1234 = cwnum/cwnom;
			cw = om1234;
			Etmp += ((1.0-pow(om1234,2.0))w21w34) *
			(1.0-tspjik)*(1.0-tspijl);

			dt1dik = (rik2i)-(dctiksink2icos321);
			dt1djk = (-dctjksink2icos321);
			dt1djl = (rjl2i)-(dctjlsinl2icos234);
			dt1dil = (-dctilsinl2icos234);
			dt1dij = (2.0/(r23magr23mag))-(dctijsink2i*cos321) -
			(dctjisinl2icos234);

			dt2dik[0] = (-r23[2]cross234[1])+(r23[1]cross234[2]);
			dt2dik[1] = (-r23[0]cross234[2])+(r23[2]cross234[0]);
			dt2dik[2] = (-r23[1]cross234[0])+(r23[0]cross234[1]);

			dt2djl[0] = (-r23[1]cross321[2])+(r23[2]cross321[1]);
			dt2djl[1] = (-r23[2]cross321[0])+(r23[0]cross321[2]);
			dt2djl[2] = (-r23[0]cross321[1])+(r23[1]cross321[0]);

			dt2dij[0] = (r21[2]cross234[1])-(r34[2]cross321[1]) -
			(r21[1]cross234[2])+(r34[1]cross321[2]);
			dt2dij[1] = (r21[0]cross234[2])-(r34[0]cross321[2]) -
			(r21[2]cross234[0])+(r34[2]cross321[0]);
			dt2dij[2] = (r21[1]cross234[0])-(r34[1]cross321[0]) -
			(r21[0]cross234[1])+(r34[0]cross321[1]);

			aa = (prefactor2.0cw/cwnom)w21w34 *
			(1.0-tspjik)*(1.0-tspijl);
			aaa1 = -prefactor(1.0-pow(om1234,2.0))
			(1.0-tspjik)*(1.0-tspijl);
			aaa2 = aaa1w21w34;
			at2 = aa*cwnum;

			fcijpc = (-dt1dijat2)+(aaa2dtsjikdctij(1.0-tspijl)) +
			(aaa2dtsijldctji*(1.0-tspjik));
			fcikpc = (-dt1dikat2)+(aaa2dtsjikdctik(1.0-tspijl));
			fcjlpc = (-dt1djlat2)+(aaa2dtsijldctjl(1.0-tspjik));
			fcjkpc = (-dt1djkat2)+(aaa2dtsjikdctjk(1.0-tspijl));
			fcilpc = (-dt1dilat2)+(aaa2dtsijldctil(1.0-tspjik));

			F23[0] = (fcijpcr23[0])+(aadt2dij[0]);
			F23[1] = (fcijpcr23[1])+(aadt2dij[1]);
			F23[2] = (fcijpcr23[2])+(aadt2dij[2]);

			F12[0] = (fcikpcr21[0])+(aadt2dik[0]);
			F12[1] = (fcikpcr21[1])+(aadt2dik[1]);
			F12[2] = (fcikpcr21[2])+(aadt2dik[2]);

			F34[0] = (fcjlpcr34[0])+(aadt2djl[0]);
			F34[1] = (fcjlpcr34[1])+(aadt2djl[1]);
			F34[2] = (fcjlpcr34[2])+(aadt2djl[2]);

			F31[0] = (fcjkpc*rjk[0]);
			F31[1] = (fcjkpc*rjk[1]);
			F31[2] = (fcjkpc*rjk[2]);

			F24[0] = (fcilpc*ril[0]);
			F24[1] = (fcilpc*ril[1]);
			F24[2] = (fcilpc*ril[2]);

			f[atom1][0] +=-F12[0]-F31[0];
			f[atom1][1] +=-F12[1]-F31[1];
			f[atom1][2] +=-F12[2]-F31[2];
			f[atom2][0] += F23[0]+F12[0]+F24[0];
			f[atom2][1] += F23[1]+F12[1]+F24[1];
			f[atom2][2] += F23[2]+F12[2]+F24[2];
			f[atom3][0] += -F23[0]+F34[0]+F31[0];
			f[atom3][1] += -F23[1]+F34[1]+F31[1];
			f[atom3][2] += -F23[2]+F34[2]+F31[2];
			f[atom4][0] += -F34[0]-F24[0];
			f[atom4][1] += -F34[1]-F24[1];
			f[atom4][2] += -F34[2]-F24[2];

			// coordination forces

			tmp2 = VATij((1.0-(om1234om1234)))
			(1.0-tspjik)(1.0-tspijl)dw21*w34/r21mag;
			f[atom2][0] -= tmp2*r21[0];
			f[atom2][1] -= tmp2*r21[1];
			f[atom2][2] -= tmp2*r21[2];
			f[atom1][0] += tmp2*r21[0];
			f[atom1][1] += tmp2*r21[1];
			f[atom1][2] += tmp2*r21[2];

			tmp2 = VATij((1.0-(om1234om1234)))
			(1.0-tspjik)(1.0-tspijl)w21*dw34/r34mag;
			f[atom3][0] -= tmp2*r34[0];
			f[atom3][1] -= tmp2*r34[1];
			f[atom3][2] -= tmp2*r34[2];
			f[atom4][0] += tmp2*r34[0];
			f[atom4][1] += tmp2*r34[1];
			f[atom4][2] += tmp2*r34[2];
			}
			}
			}
			}
			}
			}

			// Tij forces now that we have Etmp

			REBO_neighs = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs[k];
			if (atomk != atomj) {
			ktype = map[type[atomk]];
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt((rik[0]rik[0])+(rik[1]rik[1])+(rik[2]*rik[2]));
			wik = Sp(rikmag,rcmin[itype][ktype],rcmax[itype][ktype],dwik);
			Nki = nC[atomk]-(wik*kronecker(itype,0))+nH[atomk] -
			(wik*kronecker(itype,1));
			SpN = Sp(Nki,Nmin,Nmax,dNki);

			tmp2 = VAdN3[0]dwik*Etmp/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			tmp2 = VAdN3[2](2.0NconjtmpIdwikSpN)Etmp/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			if (fabs(dNki) > TOL) {
			REBO_neighs_k = REBO_firstneigh[atomk];
			for (n = 0; n < REBO_numneigh[atomk]; n++) {
			atomn = REBO_neighs_k[n];
			ntype = map[type[atomn]];
			if (atomn != atomi) {
			rkn[0] = x[atomk][0]-x[atomn][0];
			rkn[1] = x[atomk][1]-x[atomn][1];
			rkn[2] = x[atomk][2]-x[atomn][2];
			rknmag = sqrt((rkn[0]rkn[0])+(rkn[1]rkn[1])+(rkn[2]*rkn[2]));
			Sp(rknmag,rcmin[ktype][ntype],rcmax[ktype][ntype],dwkn);

			tmp2 = VAdN3[2](2.0NconjtmpIwikdNkidwkn)*Etmp/rknmag;
			f[atomk][0] -= tmp2*rkn[0];
			f[atomk][1] -= tmp2*rkn[1];
			f[atomk][2] -= tmp2*rkn[2];
			f[atomn][0] += tmp2*rkn[0];
			f[atomn][1] += tmp2*rkn[1];
			f[atomn][2] += tmp2*rkn[2];
			}
			}
			}
			}
			}

			// Tij forces

			REBO_neighs = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs[l];
			if (atoml != atomi) {
			ltype = map[type[atoml]];
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt((rjl[0]rjl[0])+(rjl[1]rjl[1])+(rjl[2]*rjl[2]));
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmax[jtype][ltype],dwjl);
			Nlj = nC[atoml]-(wjl*kronecker(jtype,0))+nH[atoml] -
			(wjl*kronecker(jtype,1));
			SpN = Sp(Nlj,Nmin,Nmax,dNlj);

			tmp2 = VAdN3[1]dwjl*Etmp/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			tmp2 = VAdN3[2](2.0NconjtmpJdwjlSpN)Etmp/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			if (fabs(dNlj) > TOL) {
			REBO_neighs_l = REBO_firstneigh[atoml];
			for (n = 0; n < REBO_numneigh[atoml]; n++) {
			atomn = REBO_neighs_l[n];
			ntype = map[type[atomn]];
			if (atomn !=atomj) {
			rln[0] = x[atoml][0]-x[atomn][0];
			rln[1] = x[atoml][1]-x[atomn][1];
			rln[2] = x[atoml][2]-x[atomn][2];
			rlnmag = sqrt((rln[0]rln[0])+(rln[1]rln[1])+(rln[2]*rln[2]));
			Sp(rlnmag,rcmin[ltype][ntype],rcmax[ltype][ntype],dwln);

			tmp2 = VAdN3[2](2.0NconjtmpJwjldNljdwln)*Etmp/rlnmag;
			f[atoml][0] -= tmp2*rln[0];
			f[atoml][1] -= tmp2*rln[1];
			f[atoml][2] -= tmp2*rln[2];
			f[atomn][0] += tmp2*rln[0];
			f[atomn][1] += tmp2*rln[1];
			f[atomn][2] += tmp2*rln[2];
			}
			}
			}
			}
			}
			}

			bij = (0.5(pij+pji))+piRC+(TijEtmp);
			return bij;
			}

			/* ----------------------------------------------------------------------
			Bij* function
			------------------------------------------------------------------------- */

			double PairAIREBO::bondorderLJ(int i, int j, double rij[3], double rijmag,
			double VA, double rij0[3], double rij0mag,
			double **f)
			{
			int k,n,l,atomk,atoml,atomn,atom1,atom2,atom3,atom4;
			int atomi,atomj,itype,jtype,ktype,ltype,ntype;
			double rik[3], rjl[3], rkn[3],rknmag,dNki;
			double NijC,NijH,NjiC,NjiH,wik,dwik,dwkn,wjl;
			double rikmag,rjlmag,cosjik,cosijl,g,tmp2,tmp3;
			double Etmp,pij,tmp,wij,dwij,NconjtmpI,NconjtmpJ;
			double Nki,Nlj,dS,lamdajik,lamdaijl,dgdc,dgdN,pji,Nijconj,piRC;
			double dcosjikdri[3],dcosijldri[3],dcosjikdrk[3];
			double dN2[2],dN3[3];
			double dcosijldrj[3],dcosijldrl[3],dcosjikdrj[3],dwjl;
			double Tij,crosskij[3],crosskijmag;
			double crossijl[3],crossijlmag,omkijl;

			double tmppij,tmppji,dN2PIJ[2],dN2PJI[2],dN3piRC[3],dN3Tij[3];
			double bij,tmp3pij,tmp3pji,Stb,dStb;
			double r32[3],r32mag,cos321;

			double om1234,rln[3];
			double rlnmag,dwln,r23[3],r23mag,r21[3],r21mag;
			double w21,dw21,r34[3],r34mag,cos234,w34,dw34;
			double cross321[3],cross234[3],prefactor,SpN;
			double fcijpc,fcikpc,fcjlpc,fcjkpc,fcilpc;
			double dt2dik[3],dt2djl[3],dt2dij[3],aa,aaa1,aaa2,at2,cw,cwnum,cwnom;
			double sin321,sin234,rr,rijrik,rijrjl,rjk2,rik2,ril2,rjl2;
			double dctik,dctjk,dctjl,dctij,dctji,dctil,rik2i,rjl2i,sink2i,sinl2i;
			double rjk[3],ril[3],dt1dik,dt1djk,dt1djl,dt1dil,dt1dij;
			double dNlj;
			double PijS,PjiS;
			double rij2,tspjik,dtsjik,tspijl,dtsijl,costmp;
			int REBO_neighs,REBO_neighs_i,REBO_neighs_j,REBO_neighs_k,*REBO_neighs_l;
			double F12[3],F23[3],F34[3],F31[3],F24[3];

			double **x = atom->x;
			int *type = atom->type;

			atomi = i;
			atomj = j;
			itype = map[type[atomi]];
			jtype = map[type[atomj]];
			wij = Sp(rij0mag,rcmin[itype][jtype],rcmax[itype][jtype],dwij);
			NijC = nC[atomi]-(wij*kronecker(jtype,0));
			NijH = nH[atomi]-(wij*kronecker(jtype,1));
			NjiC = nC[atomj]-(wij*kronecker(itype,0));
			NjiH = nH[atomj]-(wij*kronecker(itype,1));

			rij[0] = rij0[0];
			rij[1] = rij0[1];
			rij[2] = rij0[2];
			rijmag = rij0mag;

			bij = 0.0;
			tmp = 0.0;
			tmp2 = 0.0;
			tmp3 = 0.0;
			dgdc = 0.0;
			dgdN = 0.0;
			NconjtmpI = 0.0;
			NconjtmpJ = 0.0;
			Etmp = 0.0;

			REBO_neighs = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs[k];
			if (atomk != atomj) {
			ktype = map[type[atomk]];
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt((rik[0]rik[0])+(rik[1]rik[1])+(rik[2]*rik[2]));
			lamdajik = 4.0kronecker(itype,1)
			((rho[ktype][1]-rikmag)-(rho[jtype][1]-rijmag));
			wik = Sp(rikmag,rcmin[itype][ktype],rcmax[itype][ktype],dS);
			Nki = nC[atomk]-(wik*kronecker(itype,0)) +
			nH[atomk]-(wik*kronecker(itype,1));
			cosjik = ((rij[0]rik[0])+(rij[1]rik[1])+(rij[2]*rik[2])) /
			(rijmag*rikmag);
			cosjik = MIN(cosjik,1.0);
			cosjik = MAX(cosjik,-1.0);

			// evaluate splines g and derivatives dg

			g = gSpline(cosjik,(NijC+NijH),itype,&dgdc,&dgdN);
			Etmp = Etmp+(wikgexp(lamdajik));
			tmp3 = tmp3+(wikdgdNexp(lamdajik));
			NconjtmpI = NconjtmpI+(kronecker(ktype,0)wikSp(Nki,Nmin,Nmax,dS));
			}
			}

			PijS = 0.0;
			dN2PIJ[0] = 0.0;
			dN2PIJ[1] = 0.0;
			PijS = PijSpline(NijC,NijH,itype,jtype,dN2PIJ);
			pij = pow(1.0+Etmp+PijS,-0.5);
			tmppij = -.5*pow(pij,3.0);
			tmp3pij = tmp3;
			tmp = 0.0;
			tmp2 = 0.0;
			tmp3 = 0.0;
			Etmp = 0.0;

			REBO_neighs = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs[l];
			if (atoml != atomi) {
			ltype = map[type[atoml]];
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt((rjl[0]rjl[0])+(rjl[1]rjl[1])+(rjl[2]*rjl[2]));
			lamdaijl = 4.0kronecker(jtype,1)
			((rho[ltype][1]-rjlmag)-(rho[itype][1]-rijmag));
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmax[jtype][ltype],dS);
			Nlj = nC[atoml]-(wjl*kronecker(jtype,0))+nH[atoml] -
			(wjl*kronecker(jtype,1));
			cosijl = -1.0((rij[0]rjl[0])+(rij[1]rjl[1])+(rij[2]rjl[2])) /
			(rijmag*rjlmag);
			cosijl = MIN(cosijl,1.0);
			cosijl = MAX(cosijl,-1.0);

			// evaluate splines g and derivatives dg

			g = gSpline(cosijl,NjiC+NjiH,jtype,&dgdc,&dgdN);
			Etmp = Etmp+(wjlgexp(lamdaijl));
			tmp3 = tmp3+(wjldgdNexp(lamdaijl));
			NconjtmpJ = NconjtmpJ+(kronecker(ltype,0)wjlSp(Nlj,Nmin,Nmax,dS));
			}
			}

			PjiS = 0.0;
			dN2PJI[0] = 0.0;
			dN2PJI[1] = 0.0;
			PjiS = PijSpline(NjiC,NjiH,jtype,itype,dN2PJI);
			pji = pow(1.0+Etmp+PjiS,-0.5);
			tmppji = -.5*pow(pji,3.0);
			tmp3pji = tmp3;

			// evaluate Nij conj

			Nijconj = 1.0+(NconjtmpINconjtmpI)+(NconjtmpJNconjtmpJ);
			piRC = piRCSpline(NijC+NijH,NjiC+NjiH,Nijconj,itype,jtype,dN3piRC);
			Tij = 0.0;
			dN3Tij[0] = 0.0;
			dN3Tij[1] = 0.0;
			dN3Tij[2] = 0.0;
			if (itype == 0 && jtype == 0)
			Tij=TijSpline((NijC+NijH),(NjiC+NjiH),Nijconj,dN3Tij);

			Etmp = 0.0;
			if (fabs(Tij) > TOL) {
			REBO_neighs_i = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs_i[k];
			ktype = map[type[atomk]];
			if (atomk != atomj) {
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt((rik[0]rik[0])+(rik[1]rik[1])+(rik[2]*rik[2]));
			cos321 = ((rij[0]rik[0])+(rij[1]rik[1])+(rij[2]*rik[2])) /
			(rijmag*rikmag);
			cos321 = MIN(cos321,1.0);
			cos321 = MAX(cos321,-1.0);

			rjk[0] = rik[0]-rij[0];
			rjk[1] = rik[1]-rij[1];
			rjk[2] = rik[2]-rij[2];
			rjk2 = (rjk[0]rjk[0])+(rjk[1]rjk[1])+(rjk[2]*rjk[2]);
			rij2 = rijmag*rijmag;
			rik2 = rikmag*rikmag;
			costmp = 0.5*(rij2+rik2-rjk2)/rijmag/rikmag;
			tspjik = Sp2(costmp,thmin,thmax,dtsjik);

			if (sqrt(1.0 - cos321*cos321) != 0.0) {
			wik = Sp(rikmag,rcmin[itype][ktype],rcmaxp[itype][ktype],dwik);
			REBO_neighs_j = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs_j[l];
			ltype = map[type[atoml]];
			if (!(atoml == atomi \|\| atoml == atomk)) {
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt(rjl[0]rjl[0] + rjl[1]rjl[1] + rjl[2]*rjl[2]);
			cos234 = -((rij[0]rjl[0])+(rij[1]rjl[1])+(rij[2]*rjl[2])) /
			(rijmag*rjlmag);
			cos234 = MIN(cos234,1.0);
			cos234 = MAX(cos234,-1.0);

			ril[0] = rij[0]+rjl[0];
			ril[1] = rij[1]+rjl[1];
			ril[2] = rij[2]+rjl[2];
			ril2 = (ril[0]ril[0])+(ril[1]ril[1])+(ril[2]*ril[2]);
			rijrjl = 2.0rijmagrjlmag;
			rjl2 = rjlmag*rjlmag;
			costmp = 0.5*(rij2+rjl2-ril2)/rijmag/rjlmag;
			tspijl = Sp2(costmp,thmin,thmax,dtsijl);

			if (sqrt(1.0 - cos234*cos234) != 0.0) {
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmaxp[jtype][ltype],dS);
			crosskij[0] = (rij[1]rik[2]-rij[2]rik[1]);
			crosskij[1] = (rij[2]rik[0]-rij[0]rik[2]);
			crosskij[2] = (rij[0]rik[1]-rij[1]rik[0]);
			crosskijmag = sqrt(crosskij[0]*crosskij[0] +
			crosskij[1]*crosskij[1] +
			crosskij[2]*crosskij[2]);
			crossijl[0] = (rij[1]rjl[2]-rij[2]rjl[1]);
			crossijl[1] = (rij[2]rjl[0]-rij[0]rjl[2]);
			crossijl[2] = (rij[0]rjl[1]-rij[1]rjl[0]);
			crossijlmag = sqrt(crossijl[0]*crossijl[0] +
			crossijl[1]*crossijl[1] +
			crossijl[2]*crossijl[2]);
			omkijl = -1.0(((crosskij[0]crossijl[0]) +
			(crosskij[1]*crossijl[1]) +
			(crosskij[2]*crossijl[2])) /
			(crosskijmag*crossijlmag));
			Etmp += ((1.0-pow(omkijl,2.0))wikwjl) *
			(1.0-tspjik)*(1.0-tspijl);
			}
			}
			}
			}
			}
			}
			}

			bij = (.5(pij+pji))+piRC+(TijEtmp);
			Stb = Sp2(bij,bLJmin[itype][jtype],bLJmax[itype][jtype],dStb);
			VA = VA*dStb;

			if (dStb != 0.0) {
			tmp = tmppij;
			dN2[0] = dN2PIJ[0];
			dN2[1] = dN2PIJ[1];
			tmp3 = tmp3pij;

			// pij forces

			REBO_neighs_i = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs_i[k];
			if (atomk != atomj) {
			lamdajik = 0.0;
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt(rik[0]rik[0] + rik[1]rik[1] + rik[2]*rik[2]);
			lamdajik = 4.0kronecker(itype,1)
			((rho[ktype][1]-rikmag)-(rho[jtype][1]-rijmag));
			wik = Sp(rikmag,rcmin[itype][ktype],rcmax[itype][ktype],dwik);
			cosjik = ((rij[0]rik[0])+(rij[1]rik[1])+(rij[2]*rik[2])) /
			(rijmag*rikmag);
			cosjik = MIN(cosjik,1.0);
			cosjik = MAX(cosjik,-1.0);

			dcosjikdri[0] = ((rij[0]+rik[0])/(rijmag*rikmag)) -
			(cosjik((rij[0]/(rijmagrijmag))+(rik[0]/(rikmag*rikmag))));
			dcosjikdri[1] = ((rij[1]+rik[1])/(rijmag*rikmag)) -
			(cosjik((rij[1]/(rijmagrijmag))+(rik[1]/(rikmag*rikmag))));
			dcosjikdri[2] = ((rij[2]+rik[2])/(rijmag*rikmag)) -
			(cosjik((rij[2]/(rijmagrijmag))+(rik[2]/(rikmag*rikmag))));
			dcosjikdrk[0] = (-rij[0]/(rijmag*rikmag)) +
			(cosjik(rik[0]/(rikmagrikmag)));
			dcosjikdrk[1] = (-rij[1]/(rijmag*rikmag)) +
			(cosjik(rik[1]/(rikmagrikmag)));
			dcosjikdrk[2] = (-rij[2]/(rijmag*rikmag)) +
			(cosjik(rik[2]/(rikmagrikmag)));
			dcosjikdrj[0] = (-rik[0]/(rijmag*rikmag)) +
			(cosjik(rij[0]/(rijmagrijmag)));
			dcosjikdrj[1] = (-rik[1]/(rijmag*rikmag)) +
			(cosjik(rij[1]/(rijmagrijmag)));
			dcosjikdrj[2] = (-rik[2]/(rijmag*rikmag)) +
			(cosjik(rij[2]/(rijmagrijmag)));

			g = gSpline(cosjik,(NijC+NijH),itype,&dgdc,&dgdN);

			tmp2 = VA.5(tmpwikdgdc*exp(lamdajik));
			f[atomj][0] -= tmp2*dcosjikdrj[0];
			f[atomj][1] -= tmp2*dcosjikdrj[1];
			f[atomj][2] -= tmp2*dcosjikdrj[2];
			f[atomi][0] -= tmp2*dcosjikdri[0];
			f[atomi][1] -= tmp2*dcosjikdri[1];
			f[atomi][2] -= tmp2*dcosjikdri[2];
			f[atomk][0] -= tmp2*dcosjikdrk[0];
			f[atomk][1] -= tmp2*dcosjikdrk[1];
			f[atomk][2] -= tmp2*dcosjikdrk[2];

			tmp2 = VA.5(tmpwikgexp(lamdajik)4.0*kronecker(itype,1));
			f[atomj][0] -= tmp2*(-rij[0]/rijmag);
			f[atomj][1] -= tmp2*(-rij[1]/rijmag);
			f[atomj][2] -= tmp2*(-rij[2]/rijmag);
			f[atomi][0] -= tmp2*((-rik[0]/rikmag)+(rij[0]/rijmag));
			f[atomi][1] -= tmp2*((-rik[1]/rikmag)+(rij[1]/rijmag));
			f[atomi][2] -= tmp2*((-rik[2]/rikmag)+(rij[2]/rijmag));
			f[atomk][0] -= tmp2*(rik[0]/rikmag);
			f[atomk][1] -= tmp2*(rik[1]/rikmag);
			f[atomk][2] -= tmp2*(rik[2]/rikmag);

			// coordination forces

			// dwik forces

			tmp2 = VA.5(tmpdwikg*exp(lamdajik))/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			// PIJ forces

			tmp2 = VA.5(tmpdN2[ktype]dwik)/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			// dgdN forces

			tmp2 = VA.5(tmptmp3dwik)/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];
			}
			}

			tmp = tmppji;
			tmp3 = tmp3pji;
			dN2[0] = dN2PJI[0];
			dN2[1] = dN2PJI[1];
			REBO_neighs = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs[l];
			if (atoml !=atomi) {
			ltype = map[type[atoml]];
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt((rjl[0]rjl[0])+(rjl[1]rjl[1])+(rjl[2]*rjl[2]));
			lamdaijl = 4.0kronecker(jtype,1)
			((rho[ltype][1]-rjlmag)-(rho[itype][1]-rijmag));
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmax[jtype][ltype],dwjl);
			cosijl = (-1.0((rij[0]rjl[0])+(rij[1]rjl[1])+(rij[2]rjl[2]))) /
			(rijmag*rjlmag);
			cosijl = MIN(cosijl,1.0);
			cosijl = MAX(cosijl,-1.0);

			dcosijldri[0] = (-rjl[0]/(rijmag*rjlmag)) -
			(cosijlrij[0]/(rijmagrijmag));
			dcosijldri[1] = (-rjl[1]/(rijmag*rjlmag)) -
			(cosijlrij[1]/(rijmagrijmag));
			dcosijldri[2] = (-rjl[2]/(rijmag*rjlmag)) -
			(cosijlrij[2]/(rijmagrijmag));
			dcosijldrj[0] = ((-rij[0]+rjl[0])/(rijmag*rjlmag)) +
			(cosijl((rij[0]/pow(rijmag,2.0))-(rjl[0]/(rjlmagrjlmag))));
			dcosijldrj[1] = ((-rij[1]+rjl[1])/(rijmag*rjlmag)) +
			(cosijl((rij[1]/pow(rijmag,2.0))-(rjl[1]/(rjlmagrjlmag))));
			dcosijldrj[2] = ((-rij[2]+rjl[2])/(rijmag*rjlmag)) +
			(cosijl((rij[2]/pow(rijmag,2.0))-(rjl[2]/(rjlmagrjlmag))));
			dcosijldrl[0] = (rij[0]/(rijmag*rjlmag)) +
			(cosijlrjl[0]/(rjlmagrjlmag));
			dcosijldrl[1] = (rij[1]/(rijmag*rjlmag)) +
			(cosijlrjl[1]/(rjlmagrjlmag));
			dcosijldrl[2] = (rij[2]/(rijmag*rjlmag)) +
			(cosijlrjl[2]/(rjlmagrjlmag));

			// evaluate splines g and derivatives dg

			g = gSpline(cosijl,NjiC+NjiH,jtype,&dgdc,&dgdN);
			tmp2 = VA.5(tmpwjldgdc*exp(lamdaijl));
			f[atomi][0] -= tmp2*dcosijldri[0];
			f[atomi][1] -= tmp2*dcosijldri[1];
			f[atomi][2] -= tmp2*dcosijldri[2];
			f[atomj][0] -= tmp2*dcosijldrj[0];
			f[atomj][1] -= tmp2*dcosijldrj[1];
			f[atomj][2] -= tmp2*dcosijldrj[2];
			f[atoml][0] -= tmp2*dcosijldrl[0];
			f[atoml][1] -= tmp2*dcosijldrl[1];
			f[atoml][2] -= tmp2*dcosijldrl[2];

			tmp2 = VA.5(tmpwjlgexp(lamdaijl)4.0*kronecker(jtype,1));
			f[atomi][0] -= tmp2*(rij[0]/rijmag);
			f[atomi][1] -= tmp2*(rij[1]/rijmag);
			f[atomi][2] -= tmp2*(rij[2]/rijmag);
			f[atomj][0] -= tmp2*((-rjl[0]/rjlmag)-(rij[0]/rijmag));
			f[atomj][1] -= tmp2*((-rjl[1]/rjlmag)-(rij[1]/rijmag));
			f[atomj][2] -= tmp2*((-rjl[2]/rjlmag)-(rij[2]/rijmag));
			f[atoml][0] -= tmp2*(rjl[0]/rjlmag);
			f[atoml][1] -= tmp2*(rjl[1]/rjlmag);
			f[atoml][2] -= tmp2*(rjl[2]/rjlmag);

			// coordination forces
			// dwik forces

			tmp2 = VA.5(tmpdwjlg*exp(lamdaijl))/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			// PIJ forces

			tmp2 = VA.5(tmpdN2[ltype]dwjl)/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			// dgdN forces

			tmp2=VA.5(tmptmp3dwjl)/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];
			}
			}

			// piRC forces

			dN3[0] = dN3piRC[0];
			dN3[1] = dN3piRC[1];
			dN3[2] = dN3piRC[2];

			REBO_neighs_i = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs_i[k];
			if (atomk != atomj) {
			ktype = map[type[atomk]];
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt((rik[0]rik[0])+(rik[1]rik[1])+(rik[2]*rik[2]));
			wik = Sp(rikmag,rcmin[itype][ktype],rcmax[itype][ktype],dwik);
			Nki = nC[atomk]-(wik*kronecker(itype,0))+nH[atomk] -
			(wik*kronecker(itype,1));
			SpN = Sp(Nki,Nmin,Nmax,dNki);

			tmp2 = VAdN3[0]dwik/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			tmp2 = VAdN3[2](2.0NconjtmpIdwik*SpN)/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			if (fabs(dNki) > TOL) {
			REBO_neighs_k = REBO_firstneigh[atomk];
			for (n = 0; n < REBO_numneigh[atomk]; n++) {
			atomn = REBO_neighs_k[n];
			if (atomn != atomi) {
			ntype = map[type[atomn]];
			rkn[0] = x[atomk][0]-x[atomn][0];
			rkn[1] = x[atomk][1]-x[atomn][1];
			rkn[2] = x[atomk][2]-x[atomn][2];
			rknmag = sqrt((rkn[0]rkn[0])+(rkn[1]rkn[1])+(rkn[2]*rkn[2]));
			Sp(rknmag,rcmin[ktype][ntype],rcmax[ktype][ntype],dwkn);

			tmp2 = VAdN3[2](2.0NconjtmpIwikdNkidwkn)/rknmag;
			f[atomk][0] -= tmp2*rkn[0];
			f[atomk][1] -= tmp2*rkn[1];
			f[atomk][2] -= tmp2*rkn[2];
			f[atomn][0] += tmp2*rkn[0];
			f[atomn][1] += tmp2*rkn[1];
			f[atomn][2] += tmp2*rkn[2];
			}
			}
			}
			}
			}

			// piRC forces to J side

			REBO_neighs = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs[l];
			if (atoml != atomi) {
			ltype = map[type[atoml]];
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt((rjl[0]rjl[0])+(rjl[1]rjl[1])+(rjl[2]*rjl[2]));
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmax[jtype][ltype],dwjl);
			Nlj = nC[atoml]-(wjl*kronecker(jtype,0))+nH[atoml] -
			(wjl*kronecker(jtype,1));
			SpN = Sp(Nlj,Nmin,Nmax,dNlj);

			tmp2 = VAdN3[1]dwjl/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			tmp2 = VAdN3[2](2.0NconjtmpJdwjl*SpN)/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			if (fabs(dNlj) > TOL) {
			REBO_neighs_l = REBO_firstneigh[atoml];
			for (n = 0; n < REBO_numneigh[atoml]; n++) {
			atomn = REBO_neighs_l[n];
			if (atomn != atomj) {
			ntype = map[type[atomn]];
			rln[0] = x[atoml][0]-x[atomn][0];
			rln[1] = x[atoml][1]-x[atomn][1];
			rln[2] = x[atoml][2]-x[atomn][2];
			rlnmag = sqrt((rln[0]rln[0])+(rln[1]rln[1])+(rln[2]*rln[2]));
			Sp(rlnmag,rcmin[ltype][ntype],rcmax[ltype][ntype],dwln);

			tmp2 = VAdN3[2](2.0NconjtmpJwjldNljdwln)/rlnmag;
			f[atoml][0] -= tmp2*rln[0];
			f[atoml][1] -= tmp2*rln[1];
			f[atoml][2] -= tmp2*rln[2];
			f[atomn][0] += tmp2*rln[0];
			f[atomn][1] += tmp2*rln[1];
			f[atomn][2] += tmp2*rln[2];
			}
			}
			}
			}
			}

			if (fabs(Tij) > TOL) {
			dN3[0] = dN3Tij[0];
			dN3[1] = dN3Tij[1];
			dN3[2] = dN3Tij[2];
			atom2 = atomi;
			atom3 = atomj;
			r32[0] = x[atom3][0]-x[atom2][0];
			r32[1] = x[atom3][1]-x[atom2][1];
			r32[2] = x[atom3][2]-x[atom2][2];
			r32mag = sqrt((r32[0]r32[0])+(r32[1]r32[1])+(r32[2]*r32[2]));
			r23[0] = -r32[0];
			r23[1] = -r32[1];
			r23[2] = -r32[2];
			r23mag = r32mag;

			REBO_neighs_i = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs_i[k];
			atom1 = atomk;
			ktype = map[type[atomk]];
			if (atomk != atomj) {
			r21[0] = x[atom2][0]-x[atom1][0];
			r21[1] = x[atom2][1]-x[atom1][1];
			r21[2] = x[atom2][2]-x[atom1][2];
			r21mag = sqrt(r21[0]r21[0] + r21[1]r21[1] + r21[2]*r21[2]);
			cos321 = ((r21[0]rij[0])+(r21[1]rij[1])+(r21[2]*rij[2])) /
			(r21mag*rijmag);
			cos321 = MIN(cos321,1.0);
			cos321 = MAX(cos321,-1.0);
			sin321 = sqrt(1.0 - cos321*cos321);
			sink2i = 1.0/(sin321*sin321);
			rik2i = 1.0/(r21mag*r21mag);

			if (sin321 != 0.0) {
			rr = (rijmagrijmag)-(r21magr21mag);
			rjk[0] = r21[0]-rij[0];
			rjk[1] = r21[1]-rij[1];
			rjk[2] = r21[2]-rij[2];
			rjk2 = (rjk[0]rjk[0])+(rjk[1]rjk[1])+(rjk[2]*rjk[2]);
			rijrik = 2.0rijmagr21mag;
			rik2 = r21mag*r21mag;
			dctik = (-rr+rjk2)/(rijrik*rik2);
			dctij = (rr+rjk2)/(rijrikrijmagrijmag);
			dctjk = -2.0/rijrik;
			w21 = Sp(r21mag,rcmin[itype][ktype],rcmaxp[itype][ktype],dw21);
			rikmag = r21mag;
			rij2 = r32mag*r32mag;
			rik2 = r21mag*r21mag;
			costmp = 0.5*(rij2+rik2-rjk2)/rijmag/rikmag;
			tspjik = Sp2(costmp,thmin,thmax,dtsjik);
			dtsjik = -dtsjik;

			REBO_neighs_j = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs_j[l];
			atom4 = atoml;
			ltype = map[type[atoml]];
			if (!(atoml == atomi \|\| atoml == atomk)) {
			r34[0] = x[atom3][0]-x[atom4][0];
			r34[1] = x[atom3][1]-x[atom4][1];
			r34[2] = x[atom3][2]-x[atom4][2];
			r34mag = sqrt(r34[0]r34[0] + r34[1]r34[1] + r34[2]*r34[2]);
			cos234 = -1.0((rij[0]r34[0])+(rij[1]*r34[1]) +
			(rij[2]r34[2]))/(rijmagr34mag);
			cos234 = MIN(cos234,1.0);
			cos234 = MAX(cos234,-1.0);
			sin234 = sqrt(1.0 - cos234*cos234);
			sinl2i = 1.0/(sin234*sin234);
			rjl2i = 1.0/(r34mag*r34mag);

			if (sin234 != 0.0) {
			w34 = Sp(r34mag,rcmin[jtype][ltype],
			rcmaxp[jtype][ltype],dw34);
			rr = (r23magr23mag)-(r34magr34mag);
			ril[0] = r23[0]+r34[0];
			ril[1] = r23[1]+r34[1];
			ril[2] = r23[2]+r34[2];
			ril2 = (ril[0]ril[0])+(ril[1]ril[1])+(ril[2]*ril[2]);
			rijrjl = 2.0r23magr34mag;
			rjl2 = r34mag*r34mag;
			dctjl = (-rr+ril2)/(rijrjl*rjl2);
			dctji = (rr+ril2)/(rijrjlr23magr23mag);
			dctil = -2.0/rijrjl;
			rjlmag = r34mag;
			rjl2 = r34mag*r34mag;
			costmp = 0.5*(rij2+rjl2-ril2)/rijmag/rjlmag;
			tspijl = Sp2(costmp,thmin,thmax,dtsijl);
			dtsijl = -dtsijl; //need minus sign
			prefactor = VA*Tij;

			cross321[0] = (r32[1]r21[2])-(r32[2]r21[1]);
			cross321[1] = (r32[2]r21[0])-(r32[0]r21[2]);
			cross321[2] = (r32[0]r21[1])-(r32[1]r21[0]);
			cross234[0] = (r23[1]r34[2])-(r23[2]r34[1]);
			cross234[1] = (r23[2]r34[0])-(r23[0]r34[2]);
			cross234[2] = (r23[0]r34[1])-(r23[1]r34[0]);

			cwnum = (cross321[0]*cross234[0]) +
			(cross321[1]cross234[1])+(cross321[2]cross234[2]);
			cwnom = r21magr34magr23magr23magsin321*sin234;
			om1234 = cwnum/cwnom;
			cw = om1234;
			Etmp += ((1.0-pow(om1234,2.0))w21w34) *
			(1.0-tspjik)*(1.0-tspijl);

			dt1dik = (rik2i)-(dctiksink2icos321);
			dt1djk = (-dctjksink2icos321);
			dt1djl = (rjl2i)-(dctjlsinl2icos234);
			dt1dil = (-dctilsinl2icos234);
			dt1dij = (2.0/(r23mag*r23mag)) -
			(dctijsink2icos321)-(dctjisinl2icos234);

			dt2dik[0] = (-r23[2]cross234[1])+(r23[1]cross234[2]);
			dt2dik[1] = (-r23[0]cross234[2])+(r23[2]cross234[0]);
			dt2dik[2] = (-r23[1]cross234[0])+(r23[0]cross234[1]);

			dt2djl[0] = (-r23[1]cross321[2])+(r23[2]cross321[1]);
			dt2djl[1] = (-r23[2]cross321[0])+(r23[0]cross321[2]);
			dt2djl[2] = (-r23[0]cross321[1])+(r23[1]cross321[0]);

			dt2dij[0] = (r21[2]*cross234[1]) -
			(r34[2]cross321[1])-(r21[1]cross234[2]) +
			(r34[1]*cross321[2]);
			dt2dij[1] = (r21[0]*cross234[2]) -
			(r34[0]cross321[2])-(r21[2]cross234[0]) +
			(r34[2]*cross321[0]);
			dt2dij[2] = (r21[1]*cross234[0]) -
			(r34[1]cross321[0])-(r21[0]cross234[1]) +
			(r34[0]*cross321[1]);

			aa = (prefactor2.0cw/cwnom)w21w34 *
			(1.0-tspjik)*(1.0-tspijl);
			aaa1 = -prefactor(1.0-pow(om1234,2.0))
			(1.0-tspjik)*(1.0-tspijl);
			aaa2 = aaa1w21w34;
			at2 = aa*cwnum;

			fcijpc = (-dt1dijat2)+(aaa2dtsjikdctij(1.0-tspijl)) +
			(aaa2dtsijldctji*(1.0-tspjik));
			fcikpc = (-dt1dikat2)+(aaa2dtsjikdctik(1.0-tspijl));
			fcjlpc = (-dt1djlat2)+(aaa2dtsijldctjl(1.0-tspjik));
			fcjkpc = (-dt1djkat2)+(aaa2dtsjikdctjk(1.0-tspijl));
			fcilpc = (-dt1dilat2)+(aaa2dtsijldctil(1.0-tspjik));

			F23[0] = (fcijpcr23[0])+(aadt2dij[0]);
			F23[1] = (fcijpcr23[1])+(aadt2dij[1]);
			F23[2] = (fcijpcr23[2])+(aadt2dij[2]);

			F12[0] = (fcikpcr21[0])+(aadt2dik[0]);
			F12[1] = (fcikpcr21[1])+(aadt2dik[1]);
			F12[2] = (fcikpcr21[2])+(aadt2dik[2]);

			F34[0] = (fcjlpcr34[0])+(aadt2djl[0]);
			F34[1] = (fcjlpcr34[1])+(aadt2djl[1]);
			F34[2] = (fcjlpcr34[2])+(aadt2djl[2]);

			F31[0] = (fcjkpc*rjk[0]);
			F31[1] = (fcjkpc*rjk[1]);
			F31[2] = (fcjkpc*rjk[2]);

			F24[0] = (fcilpc*ril[0]);
			F24[1] = (fcilpc*ril[1]);
			F24[2] = (fcilpc*ril[2]);

			f[atom1][0] +=-F12[0]-F31[0];
			f[atom1][1] +=-F12[1]-F31[1];
			f[atom1][2] +=-F12[2]-F31[2];
			f[atom2][0] += F23[0]+F12[0]+F24[0];
			f[atom2][1] += F23[1]+F12[1]+F24[1];
			f[atom2][2] += F23[2]+F12[2]+F24[2];
			f[atom3][0] += -F23[0]+F34[0]+F31[0];
			f[atom3][1] += -F23[1]+F34[1]+F31[1];
			f[atom3][2] += -F23[2]+F34[2]+F31[2];
			f[atom4][0] += -F34[0]-F24[0];
			f[atom4][1] += -F34[1]-F24[1];
			f[atom4][2] += -F34[2]-F24[2];

			// coordination forces

			tmp2 = VATij((1.0-(om1234om1234)))
			(1.0-tspjik)(1.0-tspijl)dw21*w34/r21mag;
			f[atom2][0] -= tmp2*r21[0];
			f[atom2][1] -= tmp2*r21[1];
			f[atom2][2] -= tmp2*r21[2];
			f[atom1][0] += tmp2*r21[0];
			f[atom1][1] += tmp2*r21[1];
			f[atom1][2] += tmp2*r21[2];

			tmp2 = VATij((1.0-(om1234om1234)))
			(1.0-tspjik)(1.0-tspijl)w21*dw34/r34mag;
			f[atom3][0] -= tmp2*r34[0];
			f[atom3][1] -= tmp2*r34[1];
			f[atom3][2] -= tmp2*r34[2];
			f[atom4][0] += tmp2*r34[0];
			f[atom4][1] += tmp2*r34[1];
			f[atom4][2] += tmp2*r34[2];
			}
			}
			}
			}
			}
			}

			REBO_neighs = REBO_firstneigh[i];
			for (k = 0; k < REBO_numneigh[i]; k++) {
			atomk = REBO_neighs[k];
			if (atomk != atomj) {
			ktype = map[type[atomk]];
			rik[0] = x[atomi][0]-x[atomk][0];
			rik[1] = x[atomi][1]-x[atomk][1];
			rik[2] = x[atomi][2]-x[atomk][2];
			rikmag = sqrt((rik[0]rik[0])+(rik[1]rik[1])+(rik[2]*rik[2]));
			wik = Sp(rikmag,rcmin[itype][ktype],rcmax[itype][ktype],dwik);
			Nki = nC[atomk]-(wik*kronecker(itype,0))+nH[atomk] -
			(wik*kronecker(itype,1));
			SpN = Sp(Nki,Nmin,Nmax,dNki);

			tmp2 = VAdN3[0]dwik*Etmp/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			tmp2 = VAdN3[2](2.0NconjtmpIdwikSpN)Etmp/rikmag;
			f[atomi][0] -= tmp2*rik[0];
			f[atomi][1] -= tmp2*rik[1];
			f[atomi][2] -= tmp2*rik[2];
			f[atomk][0] += tmp2*rik[0];
			f[atomk][1] += tmp2*rik[1];
			f[atomk][2] += tmp2*rik[2];

			if (fabs(dNki) >TOL) {
			REBO_neighs_k = REBO_firstneigh[atomk];
			for (n = 0; n < REBO_numneigh[atomk]; n++) {
			atomn = REBO_neighs_k[n];
			ntype = map[type[atomn]];
			if (atomn !=atomi) {
			rkn[0] = x[atomk][0]-x[atomn][0];
			rkn[1] = x[atomk][1]-x[atomn][1];
			rkn[2] = x[atomk][2]-x[atomn][2];
			rknmag = sqrt((rkn[0]rkn[0])+(rkn[1]rkn[1])+(rkn[2]*rkn[2]));
			Sp(rknmag,rcmin[ktype][ntype],rcmax[ktype][ntype],dwkn);

			tmp2 = VAdN3[2](2.0NconjtmpIwikdNkidwkn)*Etmp/rknmag;
			f[atomk][0] -= tmp2*rkn[0];
			f[atomk][1] -= tmp2*rkn[1];
			f[atomk][2] -= tmp2*rkn[2];
			f[atomn][0] += tmp2*rkn[0];
			f[atomn][1] += tmp2*rkn[1];
			f[atomn][2] += tmp2*rkn[2];
			}
			}
			}
			}
			}

			// Tij forces

			REBO_neighs = REBO_firstneigh[j];
			for (l = 0; l < REBO_numneigh[j]; l++) {
			atoml = REBO_neighs[l];
			if (atoml != atomi) {
			ltype = map[type[atoml]];
			rjl[0] = x[atomj][0]-x[atoml][0];
			rjl[1] = x[atomj][1]-x[atoml][1];
			rjl[2] = x[atomj][2]-x[atoml][2];
			rjlmag = sqrt((rjl[0]rjl[0])+(rjl[1]rjl[1])+(rjl[2]*rjl[2]));
			wjl = Sp(rjlmag,rcmin[jtype][ltype],rcmax[jtype][ltype],dwjl);
			Nlj = nC[atoml]-(wjl*kronecker(jtype,0))+nH[atoml] -
			(wjl*kronecker(jtype,1));
			SpN = Sp(Nlj,Nmin,Nmax,dNlj);

			tmp2 = VAdN3[1]dwjl*Etmp/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			tmp2 = VAdN3[2](2.0NconjtmpJdwjlSpN)Etmp/rjlmag;
			f[atomj][0] -= tmp2*rjl[0];
			f[atomj][1] -= tmp2*rjl[1];
			f[atomj][2] -= tmp2*rjl[2];
			f[atoml][0] += tmp2*rjl[0];
			f[atoml][1] += tmp2*rjl[1];
			f[atoml][2] += tmp2*rjl[2];

			if (fabs(dNlj) > TOL) {
			REBO_neighs_l = REBO_firstneigh[atoml];
			for (n = 0; n < REBO_numneigh[atoml]; n++) {
			atomn = REBO_neighs_l[n];
			ntype = map[type[atomn]];
			if (atomn != atomj) {
			rln[0] = x[atoml][0]-x[atomn][0];
			rln[1] = x[atoml][1]-x[atomn][1];
			rln[2] = x[atoml][2]-x[atomn][2];
			rlnmag = sqrt((rln[0]rln[0])+(rln[1]rln[1])+(rln[2]*rln[2]));
			Sp(rlnmag,rcmin[ltype][ntype],rcmax[ltype][ntype],dwln);

			tmp2 = VAdN3[2](2.0NconjtmpJwjldNljdwln)*Etmp/rlnmag;
			f[atoml][0] -= tmp2*rln[0];
			f[atoml][1] -= tmp2*rln[1];
			f[atoml][2] -= tmp2*rln[2];
			f[atomn][0] += tmp2*rln[0];
			f[atomn][1] += tmp2*rln[1];
			f[atomn][2] += tmp2*rln[2];
			}
			}
			}
			}
			}
			}
			}

			return Stb;
			}

			/* ----------------------------------------------------------------------
			G spline
			------------------------------------------------------------------------- */

			double PairAIREBO::gSpline(double costh, double Nij, int typei,
			double dgdc, double dgdN)
			{
			double coeffs[6],dS,g1,g2,dg1,dg2,cut,g;
			int i,j;

			i = 0;
			j = 0;
			g = 0.0;
			cut = 0.0;
			dS = 0.0;
			dg1 = 0.0;
			dg2 = 0.0;
			*dgdc = 0.0;
			*dgdN = 0.0;

			// central atom is Carbon

			if (typei == 0) {
			if (costh < gCdom[0]) costh = gCdom[0];
			if (costh > gCdom[4]) costh = gCdom[4];
			if (Nij >= NCmax) {
			for (i = 0; i < 4; i++) {
			if (costh >= gCdom[i] && costh <= gCdom[i+1]) {
			for (j = 0; j < 6; j++) coeffs[j] = gC2[i][j];
			}
			}
			g2 = Sp5th(costh,coeffs,&dg2);
			g = g2;
			*dgdc = dg2;
			*dgdN = 0.0;
			}
			if (Nij <= NCmin) {
			for (i = 0; i < 4; i++) {
			if (costh >= gCdom[i] && costh <= gCdom[i+1]) {
			for (j = 0; j < 6; j++) coeffs[j] = gC1[i][j];
			}
			}
			g1 = Sp5th(costh,coeffs,&dg1);
			g = g1;
			*dgdc = dg1;
			*dgdN = 0.0;
			}
			if (Nij > NCmin && Nij < NCmax) {
			for (i = 0; i < 4; i++) {
			if (costh >= gCdom[i] && costh <= gCdom[i+1]) {
			for (j = 0; j < 6; j++) coeffs[j] = gC1[i][j];
			}
			}
			g1 = Sp5th(costh,coeffs,&dg1);
			for (i = 0; i < 4; i++) {
			if (costh >= gCdom[i] && costh <= gCdom[i+1]) {
			for (j = 0; j < 6; j++) coeffs[j] = gC2[i][j];
			}
			}
			g2 = Sp5th(costh,coeffs,&dg2);
			cut = Sp(Nij,NCmin,NCmax,dS);
			g = g2+cut*(g1-g2);
			dgdc = dg2+(cut(dg1-dg2));
			dgdN = dS(g1-g2);
			}
			}

			// central atom is Hydrogen

			if (typei == 1) {
			if (costh < gHdom[0]) costh = gHdom[0];
			if (costh > gHdom[3]) costh = gHdom[3];
			for (i = 0; i < 3; i++) {
			if (costh >= gHdom[i] && costh <= gHdom[i+1]) {
			for (j = 0; j < 6; j++) coeffs[j] = gH[i][j];
			}
			}
			g = Sp5th(costh,coeffs,&dg1);
			*dgdN = 0.0;
			*dgdc = dg1;
			}

			return g;
			}

			/* ----------------------------------------------------------------------
			Pij spline
			------------------------------------------------------------------------- */

			double PairAIREBO::PijSpline(double NijC, double NijH, int typei, int typej,
			double dN2[2])
			{
			int x,y,i,done;
			double Pij,coeffs[16];

			for (i = 0; i < 16; i++) coeffs[i]=0.0;

			x = 0;
			y = 0;
			dN2[0] = 0.0;
			dN2[1] = 0.0;
			done = 0;

			// if inputs are out of bounds set them back to a point in bounds

			if (typei == 0 && typej == 0) {
			if (NijC < pCCdom[0][0] \|\| NijC > pCCdom[0][1] \|\|
			NijH < pCCdom[1][0] \|\| NijH > pCCdom[1][1]) {
			NijC=0.0;
			NijH=0.0;
			}
			if (fabs(NijC-floor(NijC)) < TOL && fabs(NijH-floor(NijH)) < TOL) {
			Pij = PCCf[(int) NijC][(int) NijH];
			dN2[0] = PCCdfdx[(int) NijC][(int) NijH];
			dN2[1] = PCCdfdy[(int) NijC][(int) NijH];
			done = 1;
			}
			if (done == 0) {
			x = (int) (floor(NijC));
			y = (int) (floor(NijH));
			for (i = 0; i<16; i++) coeffs[i] = pCC[x][y][i];
			Pij = Spbicubic(NijC,NijH,coeffs,dN2);
			}
			}

			// if inputs are out of bounds set them back to a point in bounds

			if (!(typei == typej)) {
			if (NijC < pCHdom[0][0] \|\| NijC > pCHdom[0][1] \|\|
			NijH < pCHdom[1][0] \|\| NijH > pCHdom[1][1]) {
			NijC = 0.0;
			NijH = 0.0;
			}
			if (fabs(NijC-floor(NijC)) < TOL && fabs(NijH-floor(NijH)) < TOL) {
			Pij = PCHf[(int) NijC][(int) NijH];
			dN2[0] = PCHdfdx[(int) NijC][(int) NijH];
			dN2[1] = PCHdfdy[(int) NijC][(int) NijH];
			done = 1;
			}
			if (done == 0) {
			x = (int) (floor(NijC));
			y = (int) (floor(NijH));
			for (i = 0; i<16; i++) coeffs[i] = pCH[x][y][i];
			Pij = Spbicubic(NijC,NijH,coeffs,dN2);
			}
			}

			if (typei == 1 && typej == 1) {
			Pij = 0.0;
			dN2[0] = 0.0;
			dN2[1] = 0.0;
			}
			return Pij;
			}

			/* ----------------------------------------------------------------------
			PiRC spline
			------------------------------------------------------------------------- */

			double PairAIREBO::piRCSpline(double Nij, double Nji, double Nijconj,
			int typei, int typej, double dN3[3])
			{
			int x,y,z,i,done;
			double piRC,coeffs[64];
			x=0;
			y=0;
			z=0;
			i=0;

			done=0;

			for (i=0; i<64; i++) coeffs[i]=0.0;

			if (typei==0 && typej==0) {
			//if the inputs are out of bounds set them back to a point in bounds
			if (Nij<piCCdom[0][0]) Nij=piCCdom[0][0];
			if (Nji<piCCdom[1][0]) Nji=piCCdom[1][0];
			if (Nji>piCCdom[1][1]) Nji=0.0;
			if (Nijconj<piCCdom[2][0]) Nijconj=piCCdom[2][0];
			if (Nijconj>piCCdom[2][1]) Nijconj=piCCdom[2][1];

			if (fabs(Nij-floor(Nij))<TOL && fabs(Nji-floor(Nji))<TOL &&
			fabs(Nijconj-floor(Nijconj))<TOL) {
			piRC=piCCf[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[0]=piCCdfdx[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[1]=piCCdfdy[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[2]=piCCdfdz[(int) Nij][(int) Nji][(int) Nijconj];
			done=1;
			}

			if (done==0) {
			for (i=0; i<piCCdom[0][1]; i++)
			if (Nij>=(double) i && Nij<=(double) i+1 \|\| Nij==(double) i) x=i;
			for (i=0; i<piCCdom[1][1]; i++)
			if (Nji>=(double) i && Nji<=(double) i+1 \|\| Nji==(double) i) y=i;
			for (i=0; i<piCCdom[2][1]; i++)
			if (Nijconj>=(double) i && Nijconj<=(double) i+1 \|\|
			Nijconj==(double) i) z=i;

			for (i=0; i<64; i++) coeffs[i]=piCC[x][y][z][i];
			piRC=Sptricubic(Nij,Nji,Nijconj,coeffs,dN3);
			}
			}


			// CH interaction

			if (typei==0 && typej==1 \|\| typei==1 && typej==0) {
			// if the inputs are out of bounds set them back to a point in bounds

			if (Nij<piCHdom[0][0] \|\| Nij>piCHdom[0][1] \|\|
			Nji<piCHdom[1][0] \|\| Nji>piCHdom[1][1] \|\|
			Nijconj<piCHdom[2][0] \|\| Nijconj>piCHdom[2][1]) {
			if (Nij<piCHdom[0][0]) Nij=piCHdom[0][0];
			if (Nij>piCHdom[0][1]) Nij=0.0;
			if (Nji<piCHdom[1][0]) Nji=piCHdom[1][0];
			if (Nji>piCHdom[1][1]) Nji=0.0;
			if (Nijconj<piCHdom[2][0]) Nijconj=piCHdom[2][0];
			if (Nijconj>piCHdom[2][1]) Nijconj=piCHdom[2][1];
			}

			if (fabs(Nij-floor(Nij))<TOL && fabs(Nji-floor(Nji))<TOL &&
			fabs(Nijconj-floor(Nijconj))<TOL) {
			piRC=piCHf[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[0]=piCHdfdx[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[1]=piCHdfdy[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[2]=piCHdfdz[(int) Nij][(int) Nji][(int) Nijconj];
			done=1;
			}

			if (done==0) {
			for (i=0; i<piCHdom[0][1]; i++)
			if (Nij>=i && Nij<=i+1) x=i;
			for (i=0; i<piCHdom[1][1]; i++)
			if (Nji>=i && Nji<=i+1) y=i;
			for (i=0; i<piCHdom[2][1]; i++)
			if (Nijconj>=i && Nijconj<=i+1) z=i;

			for (i=0; i<64; i++) coeffs[i]=piCH[x][y][z][i];
			piRC=Sptricubic(Nij,Nji,Nijconj,coeffs,dN3);
			}
			}

			if (typei==1 && typej==1) {
			if (Nij<piHHdom[0][0] \|\| Nij>piHHdom[0][1] \|\|
			Nji<piHHdom[1][0] \|\| Nji>piHHdom[1][1] \|\|
			Nijconj<piHHdom[2][0] \|\| Nijconj>piHHdom[2][1]) {
			Nij=0.0;
			Nji=0.0;
			Nijconj=0.0;
			}
			if (fabs(Nij-floor(Nij))<TOL && fabs(Nji-floor(Nji))<TOL &&
			fabs(Nijconj-floor(Nijconj))<TOL) {
			piRC=piHHf[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[0]=piHHdfdx[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[1]=piHHdfdy[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[2]=piHHdfdz[(int) Nij][(int) Nji][(int) Nijconj];
			done=1;
			}
			if (done==0) {
			for (i=0; i<piHHdom[0][1]; i++)
			if (Nij>=i && Nij<=i+1) x=i;
			for (i=0; i<piHHdom[1][1]; i++)
			if (Nji>=i && Nji<=i+1) y=i;
			for (i=0; i<piHHdom[2][1]; i++)
			if (Nijconj>=i && Nijconj<=i+1) z=i;

			for (i=0; i<64; i++) coeffs[i]=piHH[x][y][z][i];
			piRC=Sptricubic(Nij,Nji,Nijconj,coeffs,dN3);
			}
			}

			return piRC;
			}

			/* ----------------------------------------------------------------------
			Tij spline
			------------------------------------------------------------------------- */

			double PairAIREBO::TijSpline(double Nij, double Nji,
			double Nijconj, double dN3[3])
			{
			int x,y,z,i,done;
			double Tijf,coeffs[64];

			x=0;
			y=0;
			z=0;
			i=0;
			Tijf=0.0;
			done=0;
			for (i=0; i<64; i++) coeffs[i]=0.0;

			//if the inputs are out of bounds set them back to a point in bounds

			if (Nij<Tijdom[0][0]) Nij=Tijdom[0][0];
			if (Nij>Tijdom[0][1]) Nij=Tijdom[0][1];
			if (Nji<Tijdom[1][0]) Nji=Tijdom[1][0];
			if (Nji>Tijdom[1][1]) Nji=Tijdom[1][1];
			if (Nijconj<Tijdom[2][0]) Nijconj=Tijdom[2][0];
			if (Nijconj>Tijdom[2][1]) Nijconj=Tijdom[2][1];

			if (fabs(Nij-floor(Nij))<TOL && fabs(Nji-floor(Nji))<TOL &&
			fabs(Nijconj-floor(Nijconj))<TOL) {
			Tijf=Tf[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[0]=Tdfdx[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[1]=Tdfdy[(int) Nij][(int) Nji][(int) Nijconj];
			dN3[2]=Tdfdz[(int) Nij][(int) Nji][(int) Nijconj];
			done=1;
			}

			if (done==0) {
			for (i=0; i<Tijdom[0][1]; i++)
			if (Nij>=i && Nij<=i+1) x=i;
			for (i=0; i<Tijdom[1][1]; i++)
			if (Nji>=i && Nji<=i+1) y=i;
			for (i=0; i<Tijdom[2][1]; i++)
			if (Nijconj>=i && Nijconj<=i+1) z=i;

			for (i=0; i<64; i++) coeffs[i]=Tijc[x][y][z][i];
			Tijf=Sptricubic(Nij,Nji,Nijconj,coeffs,dN3);
			}

			return Tijf;
			}

			/* ----------------------------------------------------------------------
			Kronecker delta function
			------------------------------------------------------------------------- */

			double PairAIREBO::kronecker(int a, int b)
			{
			double kd;
			if (a == b) kd = 1.0;
			else kd = 0.0;
			return kd;
			}

			/* ----------------------------------------------------------------------
			add pages to REBO neighbor list, starting at npage
			------------------------------------------------------------------------- */

			void PairAIREBO::add_pages(int npage)
			{
			maxpage += PGDELTA;
			pages = (int **)
			memory->srealloc(pages,maxpagesizeof(int ),"AIREBO:pages");
			for (int i = npage; i < maxpage; i++)
			pages[i] = (int ) memory->smalloc(pgsizesizeof(int),"AIREBO:pages[i]");
			}

			/* ----------------------------------------------------------------------
			read AIREBO potential file
			------------------------------------------------------------------------- */

			void PairAIREBO::read_file(char *filename)
			{
			int i,j,k,l,limit;
			char s[MAXLINE];

			// REBO Parameters (AIREBO)

			double rcmin_CC,rcmin_CH,rcmin_HH,rcmax_CC,rcmax_CH,
			rcmax_HH,rcmaxp_CC,rcmaxp_CH,rcmaxp_HH;
			double Q_CC,Q_CH,Q_HH,alpha_CC,alpha_CH,alpha_HH,A_CC,A_CH,A_HH;
			double BIJc_CC1,BIJc_CC2,BIJc_CC3,BIJc_CH1,BIJc_CH2,BIJc_CH3,
			BIJc_HH1,BIJc_HH2,BIJc_HH3;
			double Beta_CC1,Beta_CC2,Beta_CC3,Beta_CH1,Beta_CH2,Beta_CH3,
			Beta_HH1,Beta_HH2,Beta_HH3;
			double rho_CC,rho_CH,rho_HH;

			// LJ Parameters (AIREBO)

			double rcLJmin_CC,rcLJmin_CH,rcLJmin_HH,rcLJmax_CC,rcLJmax_CH,
			rcLJmax_HH,bLJmin_CC;
			double bLJmin_CH,bLJmin_HH,bLJmax_CC,bLJmax_CH,bLJmax_HH,
			epsilon_CC,epsilon_CH,epsilon_HH;
			double sigma_CC,sigma_CH,sigma_HH,epsilonT_CCCC,epsilonT_CCCH,epsilonT_HCCH;

			MPI_Comm_rank(world,&me);

			// read file on proc 0

			if (me == 0) {
			FILE *fp = fopen(filename,"r");
			if (fp == NULL) {
			char str[128];
			sprintf(str,"Cannot open AIREBO potential file %s",filename);
			error->one(str);
			}

			// skip initial comment lines

			while (1) {
			fgets(s,MAXLINE,fp);
			if (s[0] != '#') break;
			}

			// read parameters

			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmin_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmin_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmin_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmax_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmax_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmax_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmaxp_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmaxp_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcmaxp_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&smin);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Nmin);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Nmax);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&NCmin);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&NCmax);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Q_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Q_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Q_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&alpha_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&alpha_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&alpha_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&A_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&A_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&A_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_CC1);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_CC2);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_CC3);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_CH1);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_CH2);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_CH3);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_HH1);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_HH2);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&BIJc_HH3);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_CC1);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_CC2);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_CC3);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_CH1);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_CH2);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_CH3);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_HH1);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_HH2);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Beta_HH3);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rho_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rho_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rho_HH);

			// LJ parameters

			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcLJmin_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcLJmin_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcLJmin_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcLJmax_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcLJmax_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&rcLJmax_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&bLJmin_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&bLJmin_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&bLJmin_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&bLJmax_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&bLJmax_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&bLJmax_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&epsilon_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&epsilon_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&epsilon_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&sigma_CC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&sigma_CH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&sigma_HH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&epsilonT_CCCC);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&epsilonT_CCCH);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&epsilonT_HCCH);

			// gC spline

			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);

			// number-1 = # of domains for the spline

			fgets(s,MAXLINE,fp);
			sscanf(s,"%d",&limit);

			for (i = 0; i < limit; i++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&gCdom[i]);
			}
			fgets(s,MAXLINE,fp);
			for (i = 0; i < limit-1; i++) {
			for (j = 0; j < 6; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&gC1[i][j]);
			}
			}
			fgets(s,MAXLINE,fp);
			for (i = 0; i < limit-1; i++) {
			for (j = 0; j < 6; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&gC2[i][j]);
			}
			}

			// gH spline

			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);

			fgets(s,MAXLINE,fp);
			sscanf(s,"%d",&limit);

			for (i = 0; i < limit; i++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&gHdom[i]);
			}

			fgets(s,MAXLINE,fp);

			for (i = 0; i < limit-1; i++) {
			for (j = 0; j < 6; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&gH[i][j]);
			}
			}

			// pCC spline

			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);

			fgets(s,MAXLINE,fp);
			sscanf(s,"%d",&limit);

			for (i = 0; i < limit/2; i++) {
			for (j = 0; j < limit/2; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&pCCdom[i][j]);
			}
			}
			fgets(s,MAXLINE,fp);

			for (i = 0; i < (int) pCCdom[0][1]; i++) {
			for (j = 0; j < (int) pCCdom[1][1]; j++) {
			for (k = 0; k < 16; k++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&pCC[i][j][k]);
			}
			}
			}

			// pCH spline

			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			sscanf(s,"%d",&limit);

			for (i = 0; i < limit/2; i++) {
			for (j = 0; j < limit/2; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&pCHdom[i][j]);
			}
			}
			fgets(s,MAXLINE,fp);

			for (i = 0; i < (int) pCCdom[0][1]; i++) {
			for (j = 0; j < (int) pCCdom[1][1]; j++) {
			for (k = 0; k < 16; k++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&pCH[i][j][k]);
			}
			}
			}

			// piCC cpline

			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);

			fgets(s,MAXLINE,fp);
			sscanf(s,"%d",&limit);

			for (i = 0; i < limit/2; i++) {
			for (j = 0; j < limit/3; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&piCCdom[i][j]);
			}
			}
			fgets(s,MAXLINE,fp);

			for (i = 0; i < (int) piCCdom[0][1]; i++) {
			for (j = 0; j < (int) piCCdom[1][1]; j++) {
			for (k = 0; k < (int) piCCdom[2][1]; k++) {
			for (l = 0; l < 64; l = l+1) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&piCC[i][j][k][l]);
			}
			}
			}
			}

			// piCH spline

			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);

			fgets(s,MAXLINE,fp);
			sscanf(s,"%d",&limit);

			for (i = 0; i < limit/2; i++) {
			for (j = 0; j < limit/3; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&piCHdom[i][j]);
			}
			}
			fgets(s,MAXLINE,fp);

			for (i = 0; i < (int) piCHdom[0][1]; i++) {
			for (j = 0; j < (int) piCHdom[1][1]; j++) {
			for (k = 0; k < (int) piCHdom[2][1]; k++) {
			for (l = 0; l < 64; l = l+1) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&piCH[i][j][k][l]);
			}
			}
			}
			}

			// piHH spline

			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);

			fgets(s,MAXLINE,fp);
			sscanf(s,"%d",&limit);

			for (i = 0; i < limit/2; i++) {
			for (j = 0; j < limit/3; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&piHHdom[i][j]);
			}
			}
			fgets(s,MAXLINE,fp);

			for (i = 0; i < (int) piHHdom[0][1]; i++) {
			for (j = 0; j < (int) piHHdom[1][1]; j++) {
			for (k = 0; k < (int) piHHdom[2][1]; k++) {
			for (l = 0; l < 64; l = l+1) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&piHH[i][j][k][l]);
			}
			}
			}
			}

			// Tij spline

			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);
			fgets(s,MAXLINE,fp);

			fgets(s,MAXLINE,fp);
			sscanf(s,"%d",&limit);

			for (i = 0; i < limit/2; i++) {
			for (j = 0; j < limit/3; j++) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Tijdom[i][j]);
			}
			}
			fgets(s,MAXLINE,fp);

			for (i = 0; i < (int) Tijdom[0][1]; i++) {
			for (j = 0; j < (int) Tijdom[1][1]; j++) {
			for (k = 0; k < (int) Tijdom[2][1]; k++) {
			for (l = 0; l < 64; l = l+1) {
			fgets(s,MAXLINE,fp);
			sscanf(s,"%lg",&Tijc[i][j][k][l]);
			}
			}
			}
			}

			fclose(fp);
			}

			// store read-in values in arrays

			if (me == 0) {

			// REBO

			rcmin[0][0] = rcmin_CC;
			rcmin[0][1] = rcmin_CH;
			rcmin[1][0] = rcmin[0][1];
			rcmin[1][1] = rcmin_HH;

			rcmax[0][0] = rcmax_CC;
			rcmax[0][1] = rcmax_CH;
			rcmax[1][0] = rcmax[0][1];
			rcmax[1][1] = rcmax_HH;

			rcmaxsq[0][0] = rcmax[0][0]*rcmax[0][0];
			rcmaxsq[1][0] = rcmax[1][0]*rcmax[1][0];
			rcmaxsq[0][1] = rcmax[0][1]*rcmax[0][1];
			rcmaxsq[1][1] = rcmax[1][1]*rcmax[1][1];

			rcmaxp[0][0] = rcmaxp_CC;
			rcmaxp[0][1] = rcmaxp_CH;
			rcmaxp[1][0] = rcmaxp[0][1];
			rcmaxp[1][1] = rcmaxp_HH;

			Q[0][0] = Q_CC;
			Q[0][1] = Q_CH;
			Q[1][0] = Q[0][1];
			Q[1][1] = Q_HH;

			alpha[0][0] = alpha_CC;
			alpha[0][1] = alpha_CH;
			alpha[1][0] = alpha[0][1];
			alpha[1][1] = alpha_HH;

			A[0][0] = A_CC;
			A[0][1] = A_CH;
			A[1][0] = A[0][1];
			A[1][1] = A_HH;

			rho[0][0] = rho_CC;
			rho[0][1] = rho_CH;
			rho[1][0] = rho[0][1];
			rho[1][1] = rho_HH;

			BIJc[0][0][0] = BIJc_CC1;
			BIJc[0][0][1] = BIJc_CC2;
			BIJc[0][0][2] = BIJc_CC3;
			BIJc[0][1][0] = BIJc_CH1;
			BIJc[0][1][1] = BIJc_CH2;
			BIJc[0][1][2] = BIJc_CH3;
			BIJc[1][0][0] = BIJc_CH1;
			BIJc[1][0][1] = BIJc_CH2;
			BIJc[1][0][2] = BIJc_CH3;
			BIJc[1][1][0] = BIJc_HH1;
			BIJc[1][1][1] = BIJc_HH2;
			BIJc[1][1][2] = BIJc_HH3;

			Beta[0][0][0] = Beta_CC1;
			Beta[0][0][1] = Beta_CC2;
			Beta[0][0][2] = Beta_CC3;
			Beta[0][1][0] = Beta_CH1;
			Beta[0][1][1] = Beta_CH2;
			Beta[0][1][2] = Beta_CH3;
			Beta[1][0][0] = Beta_CH1;
			Beta[1][0][1] = Beta_CH2;
			Beta[1][0][2] = Beta_CH3;
			Beta[1][1][0] = Beta_HH1;
			Beta[1][1][1] = Beta_HH2;
			Beta[1][1][2] = Beta_HH3;

			// LJ

			rcLJmin[0][0] = rcLJmin_CC;
			rcLJmin[0][1] = rcLJmin_CH;
			rcLJmin[1][0] = rcLJmin[0][1];
			rcLJmin[1][1] = rcLJmin_HH;

			rcLJmax[0][0] = rcLJmax_CC;
			rcLJmax[0][1] = rcLJmax_CH;
			rcLJmax[1][0] = rcLJmax[0][1];
			rcLJmax[1][1] = rcLJmax_HH;

			rcLJmaxsq[0][0] = rcLJmax[0][0]*rcLJmax[0][0];
			rcLJmaxsq[1][0] = rcLJmax[1][0]*rcLJmax[1][0];
			rcLJmaxsq[0][1] = rcLJmax[0][1]*rcLJmax[0][1];
			rcLJmaxsq[1][1] = rcLJmax[1][1]*rcLJmax[1][1];

			bLJmin[0][0] = bLJmin_CC;
			bLJmin[0][1] = bLJmin_CH;
			bLJmin[1][0] = bLJmin[0][1];
			bLJmin[1][1] = bLJmin_HH;

			bLJmax[0][0] = bLJmax_CC;
			bLJmax[0][1] = bLJmax_CH;
			bLJmax[1][0] = bLJmax[0][1];
			bLJmax[1][1] = bLJmax_HH;

			epsilon[0][0] = epsilon_CC;
			epsilon[0][1] = epsilon_CH;
			epsilon[1][0] = epsilon[0][1];
			epsilon[1][1] = epsilon_HH;

			sigma[0][0] = sigma_CC;
			sigma[0][1] = sigma_CH;
			sigma[1][0] = sigma[0][1];
			sigma[1][1] = sigma_HH;

			// torsional

			thmin = -1.0;
			thmax = -0.995;
			epsilonT[0][0] = epsilonT_CCCC;
			epsilonT[0][1] = epsilonT_CCCH;
			epsilonT[1][0] = epsilonT[0][1];
			epsilonT[1][1] = epsilonT_HCCH;
			}

			// broadcast read-in and setup values

			MPI_Bcast(&thmin,1,MPI_DOUBLE,0,world);
			MPI_Bcast(&thmax,1,MPI_DOUBLE,0,world);

			MPI_Bcast(&smin,1,MPI_DOUBLE,0,world);
			MPI_Bcast(&Nmin,1,MPI_DOUBLE,0,world);
			MPI_Bcast(&Nmax,1,MPI_DOUBLE,0,world);
			MPI_Bcast(&NCmin,1,MPI_DOUBLE,0,world);
			MPI_Bcast(&NCmax,1,MPI_DOUBLE,0,world);


			MPI_Bcast(&rcmin[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rcmax[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rcmaxsq[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rcmaxp[0][0],4,MPI_DOUBLE,0,world);

			MPI_Bcast(&Q[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&alpha[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&A[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rho[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&BIJc[0][0][0],12,MPI_DOUBLE,0,world);
			MPI_Bcast(&Beta[0][0][0],12,MPI_DOUBLE,0,world);

			MPI_Bcast(&rcLJmin[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rcLJmax[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rcLJmaxsq[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rcLJmin[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rcLJmin[0][0],4,MPI_DOUBLE,0,world);

			MPI_Bcast(&rcLJmin[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&rcLJmax[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&bLJmin[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&bLJmax[0][0],4,MPI_DOUBLE,0,world);

			MPI_Bcast(&epsilon[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&sigma[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&epsilonT[0][0],4,MPI_DOUBLE,0,world);

			MPI_Bcast(&gCdom[0],5,MPI_DOUBLE,0,world);
			MPI_Bcast(&gC1[0][0],24,MPI_DOUBLE,0,world);
			MPI_Bcast(&gC2[0][0],24,MPI_DOUBLE,0,world);
			MPI_Bcast(&gHdom[0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&gH[0][0],18,MPI_DOUBLE,0,world);

			MPI_Bcast(&pCCdom[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&pCHdom[0][0],4,MPI_DOUBLE,0,world);
			MPI_Bcast(&pCC[0][0][0],256,MPI_DOUBLE,0,world);
			MPI_Bcast(&pCH[0][0][0],256,MPI_DOUBLE,0,world);

			MPI_Bcast(&piCCdom[0][0],6,MPI_DOUBLE,0,world);
			MPI_Bcast(&piCHdom[0][0],6,MPI_DOUBLE,0,world);
			MPI_Bcast(&piHHdom[0][0],6,MPI_DOUBLE,0,world);
			MPI_Bcast(&piCC[0][0][0][0],9216,MPI_DOUBLE,0,world);
			MPI_Bcast(&piCH[0][0][0][0],9216,MPI_DOUBLE,0,world);
			MPI_Bcast(&piHH[0][0][0][0],9216,MPI_DOUBLE,0,world);

			MPI_Bcast(&Tijdom[0][0],6,MPI_DOUBLE,0,world);
			MPI_Bcast(&Tijc[0][0][0][0],9216,MPI_DOUBLE,0,world);
			}

			// ----------------------------------------------------------------------
			// generic Spline functions
			// ----------------------------------------------------------------------

			/* ----------------------------------------------------------------------
			fifth order spline evaluation
			------------------------------------------------------------------------- */

			double PairAIREBO::Sp5th(double x, double coeffs[6], double *df)
			{
			double f;
			int i;
			i = 0;
			f = 0.0;
			*df = 0.0;

			for (i = 0; i<6; i++) {
			f += coeffs[i]*pow(x,((double) i));
			if (i > 0) df += coeffs[i]((double) i)*pow(x,((double) i-1.0));
			}

			return f;
			}

			/* ----------------------------------------------------------------------
			bicubic spline evaluation
			------------------------------------------------------------------------- */

			double PairAIREBO::Spbicubic(double x, double y,
			double coeffs[16], double df[2])
			{
			double f;
			int i,j,cn;

			f = 0.0;
			df[0] = 0.0;
			df[1] = 0.0;
			cn = 0;

			for (i = 0; i < 4; i++) {
			for (j = 0; j < 4; j++) {
			f += coeffs[cn]pow(x,((double) i))pow(y,((double) j));
			if (i > 0) df[0] +=
			(coeffs[cn]((double) i)pow(x,((double) i-1.0)) *
			pow(y,((double) j)));
			if (j > 0) df[1] +=
			(coeffs[cn]((double) j)pow(x,((double) i)) *
			pow(y,((double) j-1.0)));
			cn++;
			}
			}

			return f;
			}

			/* ----------------------------------------------------------------------
			tricubic spline evaluation
			------------------------------------------------------------------------- */

			double PairAIREBO::Sptricubic(double x, double y, double z,
			double coeffs[64], double df[3])
			{
			double f,ir,jr,kr;
			int i,j,k,cn;

			f = 0.0;
			df[0] = 0.0;
			df[1] = 0.0;
			df[2] = 0.0;
			cn = 0;

			for (i = 0; i < 4; i++) {
			ir = (double) i;
			for (j = 0; j < 4; j++) {
			jr = (double) j;
			for (k = 0; k < 4; k++) {
			kr = (double) k;
			f += (coeffs[cn]pow(x,ir)pow(y,jr)*pow(z,kr));
			if (i > 0) df[0] +=
			(coeffs[cn]irpow(x,ir-1.0)pow(y,jr)pow(z,kr));
			if (j > 0) df[1] +=
			(coeffs[cn]jrpow(x,ir)pow(y,jr-1.0)pow(z,kr));
			if (k > 0) df[2] +=
			(coeffs[cn]krpow(x,ir)pow(y,jr)pow(z,kr-1.0));
			cn++;
			}
			}
			}

			return f;
			}

			/* ----------------------------------------------------------------------
			initialize spline knot values
			------------------------------------------------------------------------- */

			void PairAIREBO::spline_init()
			{
			int i,j,k;

			for (i = 0; i < 5; i++) {
			for (j = 0; j < 5; j++) {
			PCCf[i][j] = 0.0;
			PCCdfdx[i][j] = 0.0;
			PCCdfdy[i][j] = 0.0;
			PCHf[i][j] = 0.0;
			PCHdfdx[i][j] = 0.0;
			PCHdfdy[i][j] = 0.0;
			}
			}

			PCCf[0][2] = -0.00050;
			PCCf[0][3] = 0.0161250;
			PCCf[1][1] = -0.010960;
			PCCf[1][2] = 0.0063260;
			PCCf[2][0] = -0.0276030;
			PCCf[2][1] = 0.003180;

			PCHf[0][1] = 0.2093370;
			PCHf[0][2] = -0.064450;
			PCHf[0][3] = -0.3039280;
			PCHf[1][0] = 0.010;
			PCHf[1][1] = -0.1251230;
			PCHf[1][2] = -0.2989050;
			PCHf[2][0] = -0.1220420;
			PCHf[2][1] = -0.3005290;
			PCHf[3][0] = -0.3075850;

			for (i = 0; i < 5; i++) {
			for (j = 0; j < 5; j++) {
			for (k = 0; k < 10; k++) {
			piCCf[i][j][k] = 0.0;
			piCCdfdx[i][j][k] = 0.0;
			piCCdfdy[i][j][k] = 0.0;
			piCCdfdz[i][j][k] = 0.0;
			piCHf[i][j][k] = 0.0;
			piCHdfdx[i][j][k] = 0.0;
			piCHdfdy[i][j][k] = 0.0;
			piCHdfdz[i][j][k] = 0.0;
			piHHf[i][j][k] = 0.0;
			piHHdfdx[i][j][k] = 0.0;
			piHHdfdy[i][j][k] = 0.0;
			piHHdfdz[i][j][k] = 0.0;
			Tf[i][j][k] = 0.0;
			Tdfdx[i][j][k] = 0.0;
			Tdfdy[i][j][k] = 0.0;
			Tdfdz[i][j][k] = 0.0;
			}
			}
			}

			for (i = 3; i < 10; i++) piCCf[0][0][i] = 0.0049590;
			piCCf[1][0][1] = 0.0216940;
			piCCf[0][1][1] = 0.0216940;
			for (i = 2; i < 10; i++) piCCf[1][0][i] = 0.0049590;
			for (i = 2; i < 10; i++) piCCf[0][1][i] = 0.0049590;
			piCCf[1][1][1] = 0.05250;
			piCCf[1][1][2] = -0.0020890;
			for (i = 3; i < 10; i++) piCCf[1][1][i] = -0.0080430;
			piCCf[2][0][1] = 0.0246990;
			piCCf[0][2][1] = 0.0246990;
			piCCf[2][0][2] = -0.0059710;
			piCCf[0][2][2] = -0.0059710;
			for (i = 3; i < 10; i++) piCCf[2][0][i] = 0.0049590;
			for (i = 3; i < 10; i++) piCCf[0][2][i] = 0.0049590;
			piCCf[2][1][1] = 0.0048250;
			piCCf[1][2][1] = 0.0048250;
			piCCf[2][1][2] = 0.0150;
			piCCf[1][2][2] = 0.0150;
			piCCf[2][1][3] = -0.010;
			piCCf[1][2][3] = -0.010;
			piCCf[2][1][4] = -0.0116890;
			piCCf[1][2][4] = -0.0116890;
			piCCf[2][1][5] = -0.0133780;
			piCCf[1][2][5] = -0.0133780;
			piCCf[2][1][6] = -0.0150670;
			piCCf[1][2][6] = -0.0150670;
			for (i = 7; i < 10; i++) piCCf[2][1][i] = -0.0150670;
			for (i = 7; i < 10; i++) piCCf[1][2][i] = -0.0150670;
			piCCf[2][2][1] = 0.0472250;
			piCCf[2][2][2] = 0.0110;
			piCCf[2][2][3] = 0.0198530;
			piCCf[2][2][4] = 0.0165440;
			piCCf[2][2][5] = 0.0132350;
			piCCf[2][2][6] = 0.0099260;
			piCCf[2][2][7] = 0.0066180;
			piCCf[2][2][8] = 0.0033090;
			piCCf[3][0][1] = -0.0998990;
			piCCf[0][3][1] = -0.0998990;
			piCCf[3][0][2] = -0.0998990;
			piCCf[0][3][2] = -0.0998990;
			for (i = 3; i < 10; i++) piCCf[3][0][i] = 0.0049590;
			for (i = 3; i < 10; i++) piCCf[0][3][i] = 0.0049590;
			piCCf[3][1][2] = -0.0624180;
			piCCf[1][3][2] = -0.0624180;
			for (i = 3; i < 10; i++) piCCf[3][1][i] = -0.0624180;
			for (i = 3; i < 10; i++) piCCf[1][3][i] = -0.0624180;
			piCCf[3][2][1] = -0.0223550;
			piCCf[2][3][1] = -0.0223550;
			for (i = 2; i < 10; i++) piCCf[3][2][i] = -0.0223550;
			for (i = 2; i < 10; i++) piCCf[2][3][i] = -0.0223550;

			piCCdfdx[2][1][1] = -0.026250;
			piCCdfdx[2][1][5] = -0.0271880;
			piCCdfdx[2][1][6] = -0.0271880;
			for (i = 7; i < 10; i++) piCCdfdx[2][1][i] = -0.0271880;
			piCCdfdx[1][3][2] = 0.0375450;
			for (i = 2; i < 10; i++) piCCdfdx[2][3][i] = 0.0624180;

			piCCdfdy[1][2][1] = -0.026250;
			piCCdfdy[1][2][5] = -0.0271880;
			piCCdfdy[1][2][6] = -0.0271880;
			for (i = 7; i < 10; i++) piCCdfdy[1][2][i] = -0.0271880;
			piCCdfdy[3][1][2] = 0.0375450;
			for (i = 2; i < 10; i++) piCCdfdy[3][2][i] = 0.0624180;

			piCCdfdz[2][1][4] = -0.0100220;
			piCCdfdz[1][2][4] = -0.0100220;
			piCCdfdz[2][1][5] = -0.0100220;
			piCCdfdz[1][2][5] = -0.0100220;
			for (i = 4; i < 10; i++) piCCdfdz[2][2][i] = -0.0033090;

			piCHf[1][1][1] = -0.050;
			piCHf[1][1][2] = -0.050;
			piCHf[1][1][3] = -0.30;
			for (i = 4; i < 10; i++) piCHf[1][1][i] = -0.050;
			for (i = 5; i < 10; i++) piCHf[2][0][i] = -0.0045240;
			for (i = 5; i < 10; i++) piCHf[0][2][i] = -0.0045240;
			piCHf[2][1][2] = -0.250;
			piCHf[1][2][2] = -0.250;
			piCHf[2][1][3] = -0.250;
			piCHf[1][2][3] = -0.250;
			piCHf[3][1][1] = -0.10;
			piCHf[1][3][1] = -0.10;
			piCHf[3][1][2] = -0.1250;
			piCHf[1][3][2] = -0.1250;
			piCHf[3][1][3] = -0.1250;
			piCHf[1][3][3] = -0.1250;
			for (i = 4; i < 10; i++) piCHf[3][1][i] = -0.10;
			for (i = 4; i < 10; i++) piCHf[1][3][i] = -0.10;

			piHHf[1][1][1] = 0.1249160;

			Tf[2][2][1] = -0.035140;
			for (i = 2; i < 10; i++) Tf[2][2][i] = -0.0040480;
			}

lammps/src/MANYBODY/pair_airebo.cpp8fb52958cee3lammm-master

pair_airebo.cppView Options

lammps/src/MANYBODY/pair_airebo.cpp
8fb52958cee3lammm-master

pair_airebo.cpp
View Options