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lammps/lib/gpu/gb_gpu_kernel.cu
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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 authors: Mike Brown (ORNL), brownw@ornl.gov
------------------------------------------------------------------------- */
#ifndef GB_GPU_KERNEL
#define GB_GPU_KERNEL
#ifdef NV_KERNEL
#include "gb_gpu_extra.h"
#endif
#define SBBITS 30
#define NEIGHMASK 0x3FFFFFFF
__inline int sbmask(int j) { return j >> SBBITS & 3; }
__inline void compute_eta_torque(numtyp m[9],numtyp m2[9], const numtyp4 shape,
numtyp ans[9])
{
numtyp den = m[3]*m[2]*m[7]-m[0]*m[5]*m[7]-
m[2]*m[6]*m[4]+m[1]*m[6]*m[5]-
m[3]*m[1]*m[8]+m[0]*m[4]*m[8];
den = (numtyp)1.0/den;
ans[0] = shape.x*(m[5]*m[1]*m2[2]+(numtyp)2.0*m[4]*m[8]*m2[0]-
m[4]*m2[2]*m[2]-(numtyp)2.0*m[5]*m2[0]*m[7]+
m2[1]*m[2]*m[7]-m2[1]*m[1]*m[8]-
m[3]*m[8]*m2[1]+m[6]*m[5]*m2[1]+
m[3]*m2[2]*m[7]-m2[2]*m[6]*m[4])*den;
ans[1] = shape.x*(m[2]*m2[0]*m[7]-m[8]*m2[0]*m[1]+
(numtyp)2.0*m[0]*m[8]*m2[1]-m[0]*m2[2]*m[5]-
(numtyp)2.0*m[6]*m[2]*m2[1]+m2[2]*m[3]*m[2]-
m[8]*m[3]*m2[0]+m[6]*m2[0]*m[5]+
m[6]*m2[2]*m[1]-m2[2]*m[0]*m[7])*den;
ans[2] = shape.x*(m[1]*m[5]*m2[0]-m[2]*m2[0]*m[4]-
m[0]*m[5]*m2[1]+m[3]*m[2]*m2[1]-
m2[1]*m[0]*m[7]-m[6]*m[4]*m2[0]+
(numtyp)2.0*m[4]*m[0]*m2[2]-(numtyp)2.0*m[3]*m2[2]*m[1]+
m[3]*m[7]*m2[0]+m[6]*m2[1]*m[1])*den;
ans[3] = shape.y*(-m[4]*m2[5]*m[2]+(numtyp)2.0*m[4]*m[8]*m2[3]+
m[5]*m[1]*m2[5]-(numtyp)2.0*m[5]*m2[3]*m[7]+
m2[4]*m[2]*m[7]-m2[4]*m[1]*m[8]-
m[3]*m[8]*m2[4]+m[6]*m[5]*m2[4]-
m2[5]*m[6]*m[4]+m[3]*m2[5]*m[7])*den;
ans[4] = shape.y*(m[2]*m2[3]*m[7]-m[1]*m[8]*m2[3]+
(numtyp)2.0*m[8]*m[0]*m2[4]-m2[5]*m[0]*m[5]-
(numtyp)2.0*m[6]*m2[4]*m[2]-m[3]*m[8]*m2[3]+
m[6]*m[5]*m2[3]+m[3]*m2[5]*m[2]-
m[0]*m2[5]*m[7]+m2[5]*m[1]*m[6])*den;
ans[5] = shape.y*(m[1]*m[5]*m2[3]-m[2]*m2[3]*m[4]-
m[0]*m[5]*m2[4]+m[3]*m[2]*m2[4]+
(numtyp)2.0*m[4]*m[0]*m2[5]-m[0]*m2[4]*m[7]+
m[1]*m[6]*m2[4]-m2[3]*m[6]*m[4]-
(numtyp)2.0*m[3]*m[1]*m2[5]+m[3]*m2[3]*m[7])*den;
ans[6] = shape.z*(-m[4]*m[2]*m2[8]+m[1]*m[5]*m2[8]+
(numtyp)2.0*m[4]*m2[6]*m[8]-m[1]*m2[7]*m[8]+
m[2]*m[7]*m2[7]-(numtyp)2.0*m2[6]*m[7]*m[5]-
m[3]*m2[7]*m[8]+m[5]*m[6]*m2[7]-
m[4]*m[6]*m2[8]+m[7]*m[3]*m2[8])*den;
ans[7] = shape.z*-(m[1]*m[8]*m2[6]-m[2]*m2[6]*m[7]-
(numtyp)2.0*m2[7]*m[0]*m[8]+m[5]*m2[8]*m[0]+
(numtyp)2.0*m2[7]*m[2]*m[6]+m[3]*m2[6]*m[8]-
m[3]*m[2]*m2[8]-m[5]*m[6]*m2[6]+
m[0]*m2[8]*m[7]-m2[8]*m[1]*m[6])*den;
ans[8] = shape.z*(m[1]*m[5]*m2[6]-m[2]*m2[6]*m[4]-
m[0]*m[5]*m2[7]+m[3]*m[2]*m2[7]-
m[4]*m[6]*m2[6]-m[7]*m2[7]*m[0]+
(numtyp)2.0*m[4]*m2[8]*m[0]+m[7]*m[3]*m2[6]+
m[6]*m[1]*m2[7]-(numtyp)2.0*m2[8]*m[3]*m[1])*den;
}
__kernel void kernel_gayberne(__global numtyp4* x_,__global numtyp4 *q,
__global numtyp4* shape, __global numtyp4* well,
__global numtyp *gum, __global numtyp2* sig_eps,
const int ntypes, __global numtyp *lshape,
__global int *dev_nbor, const int stride,
__global acctyp4 *ans, const int astride,
__global acctyp *engv, __global int *err_flag,
const int eflag, const int vflag, const int inum,
const int nall, const int t_per_atom) {
int tid=THREAD_ID_X;
int ii=mul24((int)BLOCK_ID_X,(int)(BLOCK_SIZE_X)/t_per_atom);
ii+=tid/t_per_atom;
int offset=tid%t_per_atom;
__local numtyp sp_lj[4];
sp_lj[0]=gum[3];
sp_lj[1]=gum[4];
sp_lj[2]=gum[5];
sp_lj[3]=gum[6];
acctyp energy=(acctyp)0;
acctyp4 f;
f.x=(acctyp)0;
f.y=(acctyp)0;
f.z=(acctyp)0;
acctyp4 tor;
tor.x=(acctyp)0;
tor.y=(acctyp)0;
tor.z=(acctyp)0;
acctyp virial[6];
for (int i=0; i<6; i++)
virial[i]=(acctyp)0;
if (ii<inum) {
__global int *nbor=dev_nbor+ii;
int i=*nbor;
nbor+=stride;
int numj=*nbor;
nbor+=stride;
__global int *nbor_end=nbor+mul24(stride,numj);
nbor+=mul24(offset,stride);
int n_stride=mul24(t_per_atom,stride);
numtyp4 ix=x_[i];
int itype=ix.w;
numtyp a1[9], b1[9], g1[9];
numtyp4 ishape=shape[itype];
{
numtyp t[9];
gpu_quat_to_mat_trans(q,i,a1);
gpu_times3(ishape,a1,t);
gpu_transpose_times3(a1,t,g1);
gpu_times3(well[itype],a1,t);
gpu_transpose_times3(a1,t,b1);
}
numtyp factor_lj;
for ( ; nbor<nbor_end; nbor+=n_stride) {
int j=*nbor;
factor_lj = sp_lj[sbmask(j)];
j &= NEIGHMASK;
numtyp4 jx=x_[j];
int jtype=jx.w;
// Compute r12
numtyp r12[3];
r12[0] = jx.x-ix.x;
r12[1] = jx.y-ix.y;
r12[2] = jx.z-ix.z;
numtyp ir = gpu_dot3(r12,r12);
ir = rsqrt(ir);
numtyp r = (numtyp)1.0/ir;
numtyp a2[9];
gpu_quat_to_mat_trans(q,j,a2);
numtyp u_r, dUr[3], tUr[3], eta, teta[3];
{ // Compute U_r, dUr, eta, and teta
// Compute g12
numtyp g12[9];
{
numtyp g2[9];
{
gpu_times3(shape[jtype],a2,g12);
gpu_transpose_times3(a2,g12,g2);
gpu_plus3(g1,g2,g12);
}
{ // Compute U_r and dUr
// Compute kappa
numtyp kappa[3];
gpu_mldivide3(g12,r12,kappa,err_flag);
// -- replace r12 with r12 hat
r12[0]*=ir;
r12[1]*=ir;
r12[2]*=ir;
// -- kappa is now / r
kappa[0]*=ir;
kappa[1]*=ir;
kappa[2]*=ir;
// energy
// compute u_r and dUr
numtyp uslj_rsq;
{
// Compute distance of closest approach
numtyp h12, sigma12;
sigma12 = gpu_dot3(r12,kappa);
sigma12 = rsqrt((numtyp)0.5*sigma12);
h12 = r-sigma12;
// -- kappa is now ok
kappa[0]*=r;
kappa[1]*=r;
kappa[2]*=r;
int mtype=mul24(ntypes,itype)+jtype;
numtyp sigma = sig_eps[mtype].x;
numtyp epsilon = sig_eps[mtype].y;
numtyp varrho = sigma/(h12+gum[0]*sigma);
numtyp varrho6 = varrho*varrho*varrho;
varrho6*=varrho6;
numtyp varrho12 = varrho6*varrho6;
u_r = (numtyp)4.0*epsilon*(varrho12-varrho6);
numtyp temp1 = ((numtyp)2.0*varrho12*varrho-varrho6*varrho)/sigma;
temp1 = temp1*(numtyp)24.0*epsilon;
uslj_rsq = temp1*sigma12*sigma12*sigma12*(numtyp)0.5;
numtyp temp2 = gpu_dot3(kappa,r12);
uslj_rsq = uslj_rsq*ir*ir;
dUr[0] = temp1*r12[0]+uslj_rsq*(kappa[0]-temp2*r12[0]);
dUr[1] = temp1*r12[1]+uslj_rsq*(kappa[1]-temp2*r12[1]);
dUr[2] = temp1*r12[2]+uslj_rsq*(kappa[2]-temp2*r12[2]);
}
// torque for particle 1
{
numtyp tempv[3], tempv2[3];
tempv[0] = -uslj_rsq*kappa[0];
tempv[1] = -uslj_rsq*kappa[1];
tempv[2] = -uslj_rsq*kappa[2];
gpu_row_times3(kappa,g1,tempv2);
gpu_cross3(tempv,tempv2,tUr);
}
}
}
// Compute eta
{
eta = (numtyp)2.0*lshape[itype]*lshape[jtype];
numtyp det_g12 = gpu_det3(g12);
eta = pow(eta/det_g12,gum[1]);
}
// Compute teta
numtyp temp[9], tempv[3], tempv2[3];
compute_eta_torque(g12,a1,ishape,temp);
numtyp temp1 = -eta*gum[1];
tempv[0] = temp1*temp[0];
tempv[1] = temp1*temp[1];
tempv[2] = temp1*temp[2];
gpu_cross3(a1,tempv,tempv2);
teta[0] = tempv2[0];
teta[1] = tempv2[1];
teta[2] = tempv2[2];
tempv[0] = temp1*temp[3];
tempv[1] = temp1*temp[4];
tempv[2] = temp1*temp[5];
gpu_cross3(a1+3,tempv,tempv2);
teta[0] += tempv2[0];
teta[1] += tempv2[1];
teta[2] += tempv2[2];
tempv[0] = temp1*temp[6];
tempv[1] = temp1*temp[7];
tempv[2] = temp1*temp[8];
gpu_cross3(a1+6,tempv,tempv2);
teta[0] += tempv2[0];
teta[1] += tempv2[1];
teta[2] += tempv2[2];
}
numtyp chi, dchi[3], tchi[3];
{ // Compute chi and dchi
// Compute b12
numtyp b2[9], b12[9];
{
gpu_times3(well[jtype],a2,b12);
gpu_transpose_times3(a2,b12,b2);
gpu_plus3(b1,b2,b12);
}
// compute chi_12
r12[0]*=r;
r12[1]*=r;
r12[2]*=r;
numtyp iota[3];
gpu_mldivide3(b12,r12,iota,err_flag);
// -- iota is now iota/r
iota[0]*=ir;
iota[1]*=ir;
iota[2]*=ir;
r12[0]*=ir;
r12[1]*=ir;
r12[2]*=ir;
chi = gpu_dot3(r12,iota);
chi = pow(chi*(numtyp)2.0,gum[2]);
// -- iota is now ok
iota[0]*=r;
iota[1]*=r;
iota[2]*=r;
numtyp temp1 = gpu_dot3(iota,r12);
numtyp temp2 = (numtyp)-4.0*ir*ir*gum[2]*pow(chi,(gum[2]-(numtyp)1.0)/
gum[2]);
dchi[0] = temp2*(iota[0]-temp1*r12[0]);
dchi[1] = temp2*(iota[1]-temp1*r12[1]);
dchi[2] = temp2*(iota[2]-temp1*r12[2]);
// compute t_chi
numtyp tempv[3];
gpu_row_times3(iota,b1,tempv);
gpu_cross3(tempv,iota,tchi);
temp1 = (numtyp)-4.0*ir*ir;
tchi[0] *= temp1;
tchi[1] *= temp1;
tchi[2] *= temp1;
}
numtyp temp2 = factor_lj*eta*chi;
if (eflag>0)
energy+=u_r*temp2;
numtyp temp1 = -eta*u_r*factor_lj;
if (vflag>0) {
r12[0]*=-r;
r12[1]*=-r;
r12[2]*=-r;
numtyp ft=temp1*dchi[0]-temp2*dUr[0];
f.x+=ft;
virial[0]+=r12[0]*ft;
ft=temp1*dchi[1]-temp2*dUr[1];
f.y+=ft;
virial[1]+=r12[1]*ft;
virial[3]+=r12[0]*ft;
ft=temp1*dchi[2]-temp2*dUr[2];
f.z+=ft;
virial[2]+=r12[2]*ft;
virial[4]+=r12[0]*ft;
virial[5]+=r12[1]*ft;
} else {
f.x+=temp1*dchi[0]-temp2*dUr[0];
f.y+=temp1*dchi[1]-temp2*dUr[1];
f.z+=temp1*dchi[2]-temp2*dUr[2];
}
// Torque on 1
temp1 = -u_r*eta*factor_lj;
temp2 = -u_r*chi*factor_lj;
numtyp temp3 = -chi*eta*factor_lj;
tor.x+=temp1*tchi[0]+temp2*teta[0]+temp3*tUr[0];
tor.y+=temp1*tchi[1]+temp2*teta[1]+temp3*tUr[1];
tor.z+=temp1*tchi[2]+temp2*teta[2]+temp3*tUr[2];
} // for nbor
} // if ii
// Reduce answers
if (t_per_atom>1) {
__local acctyp red_acc[7][BLOCK_PAIR];
red_acc[0][tid]=f.x;
red_acc[1][tid]=f.y;
red_acc[2][tid]=f.z;
red_acc[3][tid]=tor.x;
red_acc[4][tid]=tor.y;
red_acc[5][tid]=tor.z;
for (unsigned int s=t_per_atom/2; s>0; s>>=1) {
if (offset < s) {
for (int r=0; r<6; r++)
red_acc[r][tid] += red_acc[r][tid+s];
}
}
f.x=red_acc[0][tid];
f.y=red_acc[1][tid];
f.z=red_acc[2][tid];
tor.x=red_acc[3][tid];
tor.y=red_acc[4][tid];
tor.z=red_acc[5][tid];
if (eflag>0 || vflag>0) {
for (int r=0; r<6; r++)
red_acc[r][tid]=virial[r];
red_acc[6][tid]=energy;
for (unsigned int s=t_per_atom/2; s>0; s>>=1) {
if (offset < s) {
for (int r=0; r<7; r++)
red_acc[r][tid] += red_acc[r][tid+s];
}
}
for (int r=0; r<6; r++)
virial[r]=red_acc[r][tid];
energy=red_acc[6][tid];
}
}
// Store answers
if (ii<inum && offset==0) {
__global acctyp *ap1=engv+ii;
if (eflag>0) {
*ap1=energy;
ap1+=astride;
}
if (vflag>0) {
for (int i=0; i<6; i++) {
*ap1=virial[i];
ap1+=astride;
}
}
ans[ii]=f;
ans[ii+astride]=tor;
} // if ii
}
#endif
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