diff --git a/src/molecule.cpp b/src/molecule.cpp
index 0c00562d0..ee8f9ae42 100644
--- a/src/molecule.cpp
+++ b/src/molecule.cpp
@@ -1,1654 +1,1654 @@
 /* ----------------------------------------------------------------------
    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.
 ------------------------------------------------------------------------- */
 
 #include "stdlib.h"
 #include "string.h"
 #include "molecule.h"
 #include "atom.h"
 #include "atom_vec.h"
 #include "force.h"
 #include "comm.h"
 #include "domain.h"
 #include "math_extra.h"
 #include "math_const.h"
 #include "memory.h"
 #include "error.h"
 
 using namespace LAMMPS_NS;
 using namespace MathConst;
 
 #define MAXLINE 256
 #define EPSILON 1.0e-7
 #define BIG 1.0e20
 
 #define SINERTIA 0.4            // moment of inertia prefactor for sphere
 
 /* ---------------------------------------------------------------------- */
 
 Molecule::Molecule(LAMMPS *lmp, int narg, char **arg, int ifile) : Pointers(lmp)
 {
   me = comm->me;
 
   if (ifile >= narg) error->all(FLERR,"Illegal molecule command");
 
   int n = strlen(arg[0]) + 1;
   id = new char[n];
   strcpy(id,arg[0]);
 
   for (int i = 0; i < n-1; i++)
     if (!isalnum(id[i]) && id[i] != '_')
       error->all(FLERR,"Molecule template ID must be "
                  "alphanumeric or underscore characters");
 
   // scan args past ifile to reach optional args
   // set last = 1 if no more files in list
 
   last = 0;
   int iarg = ifile+1;
   while (iarg < narg) {
     if (strcmp(arg[iarg],"offset") == 0) break;
     iarg++;
   }
   if (iarg == ifile+1) last = 1;
 
   // parse optional args
 
   toffset = 0;
   boffset = aoffset = doffset = ioffset = 0;
 
   while (iarg < narg) {
     if (strcmp(arg[iarg],"offset") == 0) {
       if (iarg+6 > narg) error->all(FLERR,"Illegal molecule command");
       toffset = force->inumeric(FLERR,arg[iarg+1]);
       boffset = force->inumeric(FLERR,arg[iarg+2]);
       aoffset = force->inumeric(FLERR,arg[iarg+3]);
       doffset = force->inumeric(FLERR,arg[iarg+4]);
       ioffset = force->inumeric(FLERR,arg[iarg+5]);
       if (toffset < 0 || boffset < 0 || aoffset < 0 || 
           doffset < 0 || ioffset < 0) 
         error->all(FLERR,"Illegal molecule command");
       iarg += 6;
     } else error->all(FLERR,"Illegal molecule command");
   }
 
   // initialize all fields to empty
 
   initialize();
 
   // scan file for sizes of all fields and allocate them
 
   if (me == 0) open(arg[ifile]);
   read(0);
   if (me == 0) fclose(fp);
   allocate();
 
   // read file again to populate all fields
 
   if (me == 0) open(arg[ifile]);
   read(1);
   if (me == 0) fclose(fp);
 
   // stats
   
   if (me == 0) {
     if (screen)
       fprintf(screen,"Read molecule %s:\n"
               "  %d atoms with %d types\n  %d bonds with %d types\n"
               "  %d angles with %d types\n  %d dihedrals with %d types\n"
               "  %d impropers with %d types\n",
               id,natoms,ntypes,
               nbonds,nbondtypes,nangles,nangletypes,
               ndihedrals,ndihedraltypes,nimpropers,nimpropertypes);
     if (logfile)
       fprintf(logfile,"Read molecule %s:\n"
               "  %d atoms with %d types\n  %d bonds with %d types\n"
               "  %d angles with %d types\n  %d dihedrals with %d types\n"
               "  %d impropers with %d types\n",
               id,natoms,ntypes,
               nbonds,nbondtypes,nangles,nangletypes,
               ndihedrals,ndihedraltypes,nimpropers,nimpropertypes);
   }
 }
 
 /* ---------------------------------------------------------------------- */
 
 Molecule::~Molecule()
 {
   delete [] id;
   deallocate();
 }
 
 /* ----------------------------------------------------------------------
    compute center = geometric center of molecule
    also compute:
      dx = displacement of each atom from center
      molradius = radius of molecule from center including finite-size particles
 ------------------------------------------------------------------------- */
 
 void Molecule::compute_center()
 {
   if (centerflag) return;
   centerflag = 1;
 
   center[0] = center[1] = center[2] = 0.0;
   for (int i = 0; i < natoms; i++) {
     center[0] += x[i][0];
     center[1] += x[i][1];
     center[2] += x[i][2];
   }
   center[0] /= natoms;
   center[1] /= natoms;
   center[2] /= natoms;
 
   memory->destroy(dx);
   memory->create(dx,natoms,3,"molecule:dx");
 
   for (int i = 0; i < natoms; i++) {
     dx[i][0] = x[i][0] - center[0];
     dx[i][1] = x[i][1] - center[1];
     dx[i][2] = x[i][2] - center[2];
   }
 
   molradius = 0.0;
   for (int i = 0; i < natoms; i++) {
     double rad = MathExtra::len3(dx[i]);
     if (radiusflag) rad += radius[i];
     molradius = MAX(molradius,rad);
   }
 }
 
 /* ----------------------------------------------------------------------
    compute masstotal = total mass of molecule
    could have been set by user, otherwise calculate it
 ------------------------------------------------------------------------- */
 
 void Molecule::compute_mass()
 {
   if (massflag) return;
   massflag = 1;
 
   if (!rmassflag) atom->check_mass();
 
   masstotal = 0.0;
   for (int i = 0; i < natoms; i++) {
     if (rmassflag) masstotal += rmass[i];
     else masstotal += atom->mass[type[i]];
   }
 }
 
 /* ----------------------------------------------------------------------
    compute com = center of mass of molecule
    could have been set by user, otherwise calculate it
    works for finite size particles assuming no overlap
    also compute:
      dxcom = displacement of each atom from COM
      comatom = which atom (1-Natom) is nearest the COM
      maxextent = furthest any atom in molecule is from comatom (not COM)
 ------------------------------------------------------------------------- */
 
 void Molecule::compute_com()
 {
   if (!comflag) {
     comflag = 1;
 
     if (!rmassflag) atom->check_mass();
 
     double onemass;
     com[0] = com[1] = com[2] = 0.0;
     for (int i = 0; i < natoms; i++) {
       if (rmassflag) onemass = rmass[i];
       else onemass = atom->mass[type[i]];
       com[0] += x[i][0]*onemass;
       com[1] += x[i][1]*onemass;
       com[2] += x[i][2]*onemass;
     }
     com[0] /= masstotal;
     com[1] /= masstotal;
     com[2] /= masstotal;
   }
 
   memory->destroy(dxcom);
   memory->create(dxcom,natoms,3,"molecule:dxcom");
 
   for (int i = 0; i < natoms; i++) {
     dxcom[i][0] = x[i][0] - com[0];
     dxcom[i][1] = x[i][1] - com[1];
     dxcom[i][2] = x[i][2] - com[2];
   }
 
   double rsqmin = BIG;
   for (int i = 0; i < natoms; i++) {
     double rsq = MathExtra::lensq3(dxcom[i]);
     if (rsq < rsqmin) {
       comatom = i;
       rsqmin = rsq;
     }
   }
 
   double rsqmax = 0.0;
   for (int i = 0; i < natoms; i++) {
     double dx = x[comatom][0] - x[i][0];
     double dy = x[comatom][1] - x[i][1];
     double dz = x[comatom][2] - x[i][2];
     double rsq = dx*dx + dy*dy + dz*dz;
     rsqmax = MAX(rsqmax,rsq);
   }
 
   comatom++;
   maxextent = sqrt(rsqmax);
 }
 
 /* ----------------------------------------------------------------------
    compute itensor = 6 moments of inertia of molecule around xyz axes
    could have been set by user, otherwise calculate it
    accounts for finite size spheres, assuming no overlap
    also compute:
      inertia = 3 principal components of inertia
      ex,ey,ez = principal axes in space coords
      quat = quaternion for orientation of molecule
      dxbody = displacement of each atom from COM in body frame
 ------------------------------------------------------------------------- */
 
 void Molecule::compute_inertia()
 {
   if (!inertiaflag) {
     inertiaflag = 1;
 
     if (!rmassflag) atom->check_mass();
 
     double onemass,dx,dy,dz;
     for (int i = 0; i < 6; i++) itensor[i] = 0.0;
     for (int i = 0; i < natoms; i++) {
       if (rmassflag) onemass = rmass[i];
       else onemass = atom->type[type[i]];
       dx = dxcom[i][0];
       dy = dxcom[i][1];
       dz = dxcom[i][2];
       itensor[0] += onemass * (dy*dy + dz*dz);
       itensor[1] += onemass * (dx*dx + dz*dz);
       itensor[2] += onemass * (dx*dx + dy*dy);
       itensor[3] -= onemass * dy*dz;
       itensor[4] -= onemass * dx*dz;
       itensor[5] -= onemass * dx*dy;
     }
 
     if (radiusflag) {
       for (int i = 0; i < natoms; i++) {
         if (rmassflag) onemass = rmass[i];
         else onemass = atom->type[type[i]];
         itensor[0] += SINERTIA*onemass * radius[i]*radius[i];
         itensor[1] += SINERTIA*onemass * radius[i]*radius[i];
         itensor[2] += SINERTIA*onemass * radius[i]*radius[i];
       }
     }
   }
 
   // diagonalize inertia tensor for each body via Jacobi rotations
   // inertia = 3 eigenvalues = principal moments of inertia
   // evectors and exzy = 3 evectors = principal axes of rigid body
 
   double cross[3];
   double tensor[3][3],evectors[3][3];
 
   tensor[0][0] = itensor[0];
   tensor[1][1] = itensor[1];
   tensor[2][2] = itensor[2];
   tensor[1][2] = tensor[2][1] = itensor[3];
   tensor[0][2] = tensor[2][0] = itensor[4];
   tensor[0][1] = tensor[1][0] = itensor[5];
   
   if (MathExtra::jacobi(tensor,inertia,evectors))
     error->all(FLERR,"Insufficient Jacobi rotations for rigid molecule");
   
   ex[0] = evectors[0][0];
   ex[1] = evectors[1][0];
   ex[2] = evectors[2][0];
   ey[0] = evectors[0][1];
   ey[1] = evectors[1][1];
   ey[2] = evectors[2][1];
   ez[0] = evectors[0][2];
   ez[1] = evectors[1][2];
   ez[2] = evectors[2][2];
 
   // if any principal moment < scaled EPSILON, set to 0.0
   
   double max;
   max = MAX(inertia[0],inertia[1]);
   max = MAX(max,inertia[2]);
   
   if (inertia[0] < EPSILON*max) inertia[0] = 0.0;
   if (inertia[1] < EPSILON*max) inertia[1] = 0.0;
   if (inertia[2] < EPSILON*max) inertia[2] = 0.0;
   
   // enforce 3 evectors as a right-handed coordinate system
   // flip 3rd vector if needed
   
   MathExtra::cross3(ex,ey,cross);
   if (MathExtra::dot3(cross,ez) < 0.0) MathExtra::negate3(ez);
   
   // create quaternion
   
   MathExtra::exyz_to_q(ex,ey,ez,quat);
 
   // compute displacements in body frame defined by quat
 
   memory->destroy(dxbody);
   memory->create(dxbody,natoms,3,"molecule:dxbody");
 
   for (int i = 0; i < natoms; i++)
     MathExtra::transpose_matvec(ex,ey,ez,dxcom[i],dxbody[i]);
 }
 
 /* ----------------------------------------------------------------------
    read molecule info from file
    flag = 0, just scan for sizes of fields
    flag = 1, read and store fields
 ------------------------------------------------------------------------- */
 
 void Molecule::read(int flag)
 {
   char line[MAXLINE],keyword[MAXLINE];
   char *eof,*ptr;
 
   // skip 1st line of file
 
   if (me == 0) {
     eof = fgets(line,MAXLINE,fp);
     if (eof == NULL) error->one(FLERR,"Unexpected end of molecule file");
   }
 
   // read header lines
   // skip blank lines or lines that start with "#"
   // stop when read an unrecognized line
 
   while (1) {
 
     readline(line);
 
     // trim anything from '#' onward
     // if line is blank, continue
 
     if ((ptr = strchr(line,'#'))) *ptr = '\0';
     if (strspn(line," \t\n\r") == strlen(line)) continue;
 
     // search line for header keywords and set corresponding variable
 
     if (strstr(line,"atoms")) sscanf(line,"%d",&natoms);
     else if (strstr(line,"bonds")) sscanf(line,"%d",&nbonds);
     else if (strstr(line,"angles")) sscanf(line,"%d",&nangles);
     else if (strstr(line,"dihedrals")) sscanf(line,"%d",&ndihedrals);
     else if (strstr(line,"impropers")) sscanf(line,"%d",&nimpropers);
 
     else if (strstr(line,"mass")) {
       massflag = 1;
       sscanf(line,"%lg",&masstotal);
     }
     else if (strstr(line,"com")) {
       comflag = 1;
       sscanf(line,"%lg %lg %lg",&com[0],&com[1],&com[2]);
       if (domain->dimension == 2 && com[2] != 0.0)
         error->all(FLERR,"Molecule file z center-of-mass must be 0.0 for 2d");
     }
     else if (strstr(line,"inertia")) {
       inertiaflag = 1;
       sscanf(line,"%lg %lg %lg %lg %lg %lg",
              &itensor[0],&itensor[1],&itensor[2],
              &itensor[3],&itensor[4],&itensor[5]);
     }
 
     else break;
   }
 
   // error checks
 
   if (natoms < 1) error->all(FLERR,"No or invalid atom count in molecule file");
-  if (bonds < 0) error->all(FLERR,"Invalid bond count in molecule file");
-  if (angles < 0) error->all(FLERR,"Invalid angle count in molecule file");
-  if (dihedrals < 0) error->all(FLERR,"Invalid dihedral count in molecule file");
-  if (impropers < 0) error->all(FLERR,"Invalid improper count in molecule file");
+  if (nbonds < 0) error->all(FLERR,"Invalid bond count in molecule file");
+  if (nangles < 0) error->all(FLERR,"Invalid angle count in molecule file");
+  if (ndihedrals < 0) error->all(FLERR,"Invalid dihedral count in molecule file");
+  if (nimpropers < 0) error->all(FLERR,"Invalid improper count in molecule file");
 
   // count = vector for tallying bonds,angles,etc per atom
 
   if (flag == 0) memory->create(count,natoms,"molecule:count");
   else count = NULL;
   
   // grab keyword and skip next line
 
   parse_keyword(0,line,keyword);
   readline(line);
 
   // loop over sections of molecule file
 
   while (strlen(keyword)) {
     if (strcmp(keyword,"Coords") == 0) {
       xflag = 1;
       if (flag) coords(line);
       else skip_lines(natoms,line);
     } else if (strcmp(keyword,"Types") == 0) {
       typeflag = 1;
       if (flag) types(line);
       else skip_lines(natoms,line);
     } else if (strcmp(keyword,"Charges") == 0) {
       qflag = 1;
       if (flag) charges(line);
       else skip_lines(natoms,line);
     } else if (strcmp(keyword,"Diameters") == 0) {
       radiusflag = 1;
       if (flag) diameters(line);
       else skip_lines(natoms,line);
     } else if (strcmp(keyword,"Masses") == 0) {
       rmassflag = 1;
       if (flag) masses(line);
       else skip_lines(natoms,line);
 
     } else if (strcmp(keyword,"Bonds") == 0) {
       if (nbonds == 0)
 	error->all(FLERR,"Molecule file has bonds but no nbonds setting");
       bondflag = tag_require = 1;
       bonds(flag,line);
     } else if (strcmp(keyword,"Angles") == 0) {
       if (nangles == 0) 
 	error->all(FLERR,"Molecule file has angles but no nangles setting");
       angleflag = tag_require = 1;
       angles(flag,line);
     } else if (strcmp(keyword,"Dihedrals") == 0) {
       if (ndihedrals == 0) error->all(FLERR,"Molecule file has dihedrals "
 				      "but no ndihedrals setting");
       dihedralflag = tag_require = 1;
       dihedrals(flag,line);
     } else if (strcmp(keyword,"Impropers") == 0) {
       if (nimpropers == 0) error->all(FLERR,"Molecule file has impropers "
 				      "but no nimpropers setting");
       improperflag = tag_require = 1;
       impropers(flag,line);
 
     } else if (strcmp(keyword,"Special Bond Counts") == 0) {
       nspecialflag = 1;
       nspecial_read(flag,line);
     } else if (strcmp(keyword,"Special Bonds") == 0) {
       specialflag = tag_require = 1;
       if (flag) special_read(line);
       else skip_lines(natoms,line);
 
     } else if (strcmp(keyword,"Shake Flags") == 0) {
       shakeflagflag = 1;
       if (flag) shakeflag_read(line);
       else skip_lines(natoms,line);
     } else if (strcmp(keyword,"Shake Atoms") == 0) {
       shakeatomflag = tag_require = 1;
       if (shaketypeflag) shakeflag = 1;
       if (!shakeflagflag) 
 	error->all(FLERR,"Molecule file shake flags not before shake atoms");
       if (flag) shakeatom_read(line);
       else skip_lines(natoms,line);
     } else if (strcmp(keyword,"Shake Bond Types") == 0) {
       shaketypeflag = 1;
       if (shakeatomflag) shakeflag = 1;
       if (!shakeflagflag) 
 	error->all(FLERR,"Molecule file shake flags not before shake bonds");
       if (flag) shaketype_read(line);
       else skip_lines(natoms,line);
 
     } else error->one(FLERR,"Unknown section in molecule file");
 	     
     parse_keyword(1,line,keyword);
   }
 
   // clean up
 
   memory->destroy(count);
 
   // error check
 
   if (flag == 0) {
     if ((nspecialflag && !specialflag) || (!nspecialflag && specialflag))
       error->all(FLERR,"Molecule file needs both Special Bond sections");
     if (specialflag && !bondflag) 
       error->all(FLERR,"Molecule file has special flags but no bonds");
     if ((shakeflagflag || shakeatomflag || shaketypeflag) && !shakeflag)
       error->all(FLERR,"Molecule file shake info is incomplete");
   }
 
   // auto-generate special bonds
 
   if (bondflag && !specialflag) {
     specialflag = 1;
     nspecialflag = 1;
     maxspecial = atom->maxspecial;
     if (flag) special_generate();
   }
 }
 
 /* ----------------------------------------------------------------------
    read coords from file
 ------------------------------------------------------------------------- */
 
 void Molecule::coords(char *line)
 {
   int tmp;
   for (int i = 0; i < natoms; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 4) 
         error->all(FLERR,"Invalid Coords section in molecule file");
     }
     sscanf(line,"%d %lg %lg %lg",&tmp,&x[i][0],&x[i][1],&x[i][2]);
   }
 
   if (domain->dimension == 2) {
     for (int i = 0; i < natoms; i++)
       if (x[i][2] != 0.0) 
         error->all(FLERR,"Molecule file z coord must be 0.0 for 2d");
   }
 }
 
 /* ----------------------------------------------------------------------
    read types from file
    set ntypes = max of any atom type
 ------------------------------------------------------------------------- */
 
 void Molecule::types(char *line)
 {
   int tmp;
   for (int i = 0; i < natoms; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 2) 
         error->all(FLERR,"Invalid Types section in molecule file");
     }
     sscanf(line,"%d %d",&tmp,&type[i]);
     type[i] += toffset;
   }
 
   for (int i = 0; i < natoms; i++)
     if (type[i] <= 0)
       error->all(FLERR,"Invalid atom type in molecule file");
 
   for (int i = 0; i < natoms; i++)
     ntypes = MAX(ntypes,type[i]);
 }
 
 /* ----------------------------------------------------------------------
    read charges from file
 ------------------------------------------------------------------------- */
 
 void Molecule::charges(char *line)
 {
   int tmp;
   for (int i = 0; i < natoms; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 2) 
         error->all(FLERR,"Invalid Charges section in molecule file");
     }
     sscanf(line,"%d %lg",&tmp,&q[i]);
   }
 }
 
 /* ----------------------------------------------------------------------
    read diameters from file and set radii
 ------------------------------------------------------------------------- */
 
 void Molecule::diameters(char *line)
 {
   int tmp;
   maxradius = 0.0;
   for (int i = 0; i < natoms; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 2) 
         error->all(FLERR,"Invalid Diameters section in molecule file");
     }
     sscanf(line,"%d %lg",&tmp,&radius[i]);
     radius[i] *= 0.5;
     maxradius = MAX(maxradius,radius[i]);
   }
 
   for (int i = 0; i < natoms; i++)
     if (radius[i] < 0.0) 
       error->all(FLERR,"Invalid atom diameter in molecule file");
 }
 
 /* ----------------------------------------------------------------------
    read masses from file
 ------------------------------------------------------------------------- */
 
 void Molecule::masses(char *line)
 {
   int tmp;
   for (int i = 0; i < natoms; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 2) 
         error->all(FLERR,"Invalid Masses section in molecule file");
     }
     sscanf(line,"%d %lg",&tmp,&rmass[i]);
   }
 
   for (int i = 0; i < natoms; i++)
     if (rmass[i] <= 0.0) error->all(FLERR,"Invalid atom mass in molecule file");
 }
 
 /* ----------------------------------------------------------------------
    read bonds from file
    set nbondtypes = max type of any bond
    store each with both atoms if newton_bond = 0
    if flag = 0, just count bonds/atom
    if flag = 1, store them with atoms
 ------------------------------------------------------------------------- */
 
 void Molecule::bonds(int flag, char *line)
 {
   int tmp,itype;
   tagint m,atom1,atom2;
   int newton_bond = force->newton_bond;
 
   if (flag == 0)
     for (int i = 0; i < natoms; i++) count[i] = 0;
   else
     for (int i = 0; i < natoms; i++) num_bond[i] = 0;
 
   for (int i = 0; i < nbonds; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 4) 
         error->all(FLERR,"Invalid Bonds section in molecule file");
     }
     sscanf(line,"%d %d " TAGINT_FORMAT " " TAGINT_FORMAT,
            &tmp,&itype,&atom1,&atom2);
     itype += boffset;
 
     if (atom1 <= 0 || atom1 > natoms ||
 	atom2 <= 0 || atom2 > natoms)
       error->one(FLERR,"Invalid atom ID in Bonds section of molecule file");
     if (itype <= 0)
       error->one(FLERR,"Invalid bond type in Bonds section of molecule file");
 
     if (flag) {
       m = atom1-1;
       nbondtypes = MAX(nbondtypes,itype);
       bond_type[m][num_bond[m]] = itype;
       bond_atom[m][num_bond[m]] = atom2;
       num_bond[m]++;
       if (newton_bond == 0) {
 	m = atom2-1;
 	bond_type[m][num_bond[m]] = itype;
 	bond_atom[m][num_bond[m]] = atom1;
 	num_bond[m]++;
       }
     } else {
       count[atom1-1]++;
       if (newton_bond == 0) count[atom2-1]++;
     }
   }
 
   // bond_per_atom = max of count vector
 
   if (flag == 0) {
     bond_per_atom = 0;
     for (int i = 0; i < natoms; i++)
       bond_per_atom = MAX(bond_per_atom,count[i]);
   }
 }
 
 /* ----------------------------------------------------------------------
    read angles from file
    store each with all 3 atoms if newton_bond = 0
    if flag = 0, just count angles/atom
    if flag = 1, store them with atoms
 ------------------------------------------------------------------------- */
 
 void Molecule::angles(int flag, char *line)
 {
   int tmp,itype;
   tagint m,atom1,atom2,atom3;
   int newton_bond = force->newton_bond;
 
   if (flag == 0)
     for (int i = 0; i < natoms; i++) count[i] = 0;
   else
     for (int i = 0; i < natoms; i++) num_angle[i] = 0;
 
   for (int i = 0; i < nangles; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 5) 
         error->all(FLERR,"Invalid Angles section in molecule file");
     }
     sscanf(line,"%d %d " TAGINT_FORMAT " " TAGINT_FORMAT " " TAGINT_FORMAT,
            &tmp,&itype,&atom1,&atom2,&atom3);
     itype += aoffset;
 
     if (atom1 <= 0 || atom1 > natoms ||
         atom2 <= 0 || atom2 > natoms ||
         atom3 <= 0 || atom3 > natoms)
       error->one(FLERR,"Invalid atom ID in Angles section of molecule file");
     if (itype <= 0)
       error->one(FLERR,"Invalid angle type in Angles section of molecule file");
 
     if (flag) {
       m = atom2-1;
       nangletypes = MAX(nangletypes,itype);
       angle_type[m][num_angle[m]] = itype;
       angle_atom1[m][num_angle[m]] = atom1;
       angle_atom2[m][num_angle[m]] = atom2;
       angle_atom3[m][num_angle[m]] = atom3;
       num_angle[m]++;
       if (newton_bond == 0) {
 	m = atom1-1;
 	angle_type[m][num_angle[m]] = itype;
 	angle_atom1[m][num_angle[m]] = atom1;
 	angle_atom2[m][num_angle[m]] = atom2;
 	angle_atom3[m][num_angle[m]] = atom3;
 	num_angle[m]++;
 	m = atom3-1;
 	angle_type[m][num_angle[m]] = itype;
 	angle_atom1[m][num_angle[m]] = atom1;
 	angle_atom2[m][num_angle[m]] = atom2;
 	angle_atom3[m][num_angle[m]] = atom3;
 	num_angle[m]++;
       }
     } else {
       count[atom2-1]++;
       if (newton_bond == 0) {
 	count[atom1-1]++;
 	count[atom3-1]++;
       }
     }
   }
 
   // angle_per_atom = max of count vector
 
   if (flag == 0) {
     angle_per_atom = 0;
     for (int i = 0; i < natoms; i++)
       angle_per_atom = MAX(angle_per_atom,count[i]);
   }
 }
 
 /* ----------------------------------------------------------------------
    read dihedrals from file
    store each with all 4 atoms if newton_bond = 0
    if flag = 0, just count dihedrals/atom
    if flag = 1, store them with atoms
 ------------------------------------------------------------------------- */
 
 void Molecule::dihedrals(int flag, char *line)
 {
   int tmp,itype;
   tagint m,atom1,atom2,atom3,atom4;
   int newton_bond = force->newton_bond;
 
   if (flag == 0)
     for (int i = 0; i < natoms; i++) count[i] = 0;
   else
     for (int i = 0; i < natoms; i++) num_dihedral[i] = 0;
 
   for (int i = 0; i < ndihedrals; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 6) 
         error->all(FLERR,"Invalid Dihedrals section in molecule file");
     }
     sscanf(line,"%d %d " TAGINT_FORMAT " " TAGINT_FORMAT " " 
            TAGINT_FORMAT " " TAGINT_FORMAT " ",
            &tmp,&itype,&atom1,&atom2,&atom3,&atom4);
     itype += doffset;
 
     if (atom1 <= 0 || atom1 > natoms ||
         atom2 <= 0 || atom2 > natoms ||
         atom3 <= 0 || atom3 > natoms ||
         atom4 <= 0 || atom4 > natoms)
       error->one(FLERR,
 		 "Invalid atom ID in dihedrals section of molecule file");
     if (itype <= 0)
       error->one(FLERR,
 		 "Invalid dihedral type in dihedrals section of molecule file");
 
     if (flag) {
       m = atom2-1;
       ndihedraltypes = MAX(ndihedraltypes,itype);
       dihedral_type[m][num_dihedral[m]] = itype;
       dihedral_atom1[m][num_dihedral[m]] = atom1;
       dihedral_atom2[m][num_dihedral[m]] = atom2;
       dihedral_atom3[m][num_dihedral[m]] = atom3;
       dihedral_atom4[m][num_dihedral[m]] = atom4;
       num_dihedral[m]++;
       if (newton_bond == 0) {
 	m = atom1-1;
 	dihedral_type[m][num_dihedral[m]] = itype;
 	dihedral_atom1[m][num_dihedral[m]] = atom1;
 	dihedral_atom2[m][num_dihedral[m]] = atom2;
 	dihedral_atom3[m][num_dihedral[m]] = atom3;
 	dihedral_atom4[m][num_dihedral[m]] = atom4;
 	num_dihedral[m]++;
 	m = atom3-1;
 	dihedral_type[m][num_dihedral[m]] = itype;
 	dihedral_atom1[m][num_dihedral[m]] = atom1;
 	dihedral_atom2[m][num_dihedral[m]] = atom2;
 	dihedral_atom3[m][num_dihedral[m]] = atom3;
 	dihedral_atom4[m][num_dihedral[m]] = atom4;
 	num_dihedral[m]++;
 	m = atom4-1;
 	dihedral_type[m][num_dihedral[m]] = itype;
 	dihedral_atom1[m][num_dihedral[m]] = atom1;
 	dihedral_atom2[m][num_dihedral[m]] = atom2;
 	dihedral_atom3[m][num_dihedral[m]] = atom3;
 	dihedral_atom4[m][num_dihedral[m]] = atom4;
 	num_dihedral[m]++;
       }
     } else {
       count[atom2-1]++;
       if (newton_bond == 0) {
 	count[atom1-1]++;
 	count[atom3-1]++;
 	count[atom4-1]++;
       }
     }
   }
 
   // dihedral_per_atom = max of count vector
 
   if (flag == 0) {
     dihedral_per_atom = 0;
     for (int i = 0; i < natoms; i++)
       dihedral_per_atom = MAX(dihedral_per_atom,count[i]);
   }
 }
 
 /* ----------------------------------------------------------------------
    read impropers from file
    store each with all 4 atoms if newton_bond = 0
    if flag = 0, just count impropers/atom
    if flag = 1, store them with atoms
 ------------------------------------------------------------------------- */
 
 void Molecule::impropers(int flag, char *line)
 {
   int tmp,itype;
   tagint m,atom1,atom2,atom3,atom4;
   int newton_bond = force->newton_bond;
 
   if (flag == 0)
     for (int i = 0; i < natoms; i++) count[i] = 0;
   else
     for (int i = 0; i < natoms; i++) num_improper[i] = 0;
 
   for (int i = 0; i < nimpropers; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 6) 
         error->all(FLERR,"Invalid Impropers section in molecule file");
     }
     sscanf(line,"%d %d " TAGINT_FORMAT " " TAGINT_FORMAT " " 
            TAGINT_FORMAT " " TAGINT_FORMAT " ",
            &tmp,&itype,&atom1,&atom2,&atom3,&atom4);
     itype += ioffset;
 
     if (atom1 <= 0 || atom1 > natoms ||
         atom2 <= 0 || atom2 > natoms ||
         atom3 <= 0 || atom3 > natoms ||
         atom4 <= 0 || atom4 > natoms)
       error->one(FLERR,
 		 "Invalid atom ID in impropers section of molecule file");
     if (itype <= 0)
       error->one(FLERR,
 		 "Invalid improper type in impropers section of molecule file");
 
     if (flag) {
       m = atom2-1;
       nimpropertypes = MAX(nimpropertypes,itype);
       improper_type[m][num_improper[m]] = itype;
       improper_atom1[m][num_improper[m]] = atom1;
       improper_atom2[m][num_improper[m]] = atom2;
       improper_atom3[m][num_improper[m]] = atom3;
       improper_atom4[m][num_improper[m]] = atom4;
       num_improper[m]++;
       if (newton_bond == 0) {
 	m = atom1-1;
 	improper_type[m][num_improper[m]] = itype;
 	improper_atom1[m][num_improper[m]] = atom1;
 	improper_atom2[m][num_improper[m]] = atom2;
 	improper_atom3[m][num_improper[m]] = atom3;
 	improper_atom4[m][num_improper[m]] = atom4;
 	num_improper[m]++;
 	m = atom3-1;
 	improper_type[m][num_improper[m]] = itype;
 	improper_atom1[m][num_improper[m]] = atom1;
 	improper_atom2[m][num_improper[m]] = atom2;
 	improper_atom3[m][num_improper[m]] = atom3;
 	improper_atom4[m][num_improper[m]] = atom4;
 	num_improper[m]++;
 	m = atom4-1;
 	improper_type[m][num_improper[m]] = itype;
 	improper_atom1[m][num_improper[m]] = atom1;
 	improper_atom2[m][num_improper[m]] = atom2;
 	improper_atom3[m][num_improper[m]] = atom3;
 	improper_atom4[m][num_improper[m]] = atom4;
 	num_improper[m]++;
       }
     } else {
       count[atom2-1]++;
       if (newton_bond == 0) {
 	count[atom1-1]++;
 	count[atom3-1]++;
 	count[atom4-1]++;
       }
     }
   }
 
   // improper_per_atom = max of count vector
 
   if (flag == 0) {
     improper_per_atom = 0;
     for (int i = 0; i < natoms; i++)
       improper_per_atom = MAX(improper_per_atom,count[i]);
   }
 }
 
 /* ----------------------------------------------------------------------
    read 3 special bonds counts from file
    if flag = 0, just tally maxspecial
    if flag = 1, store them with atoms
 ------------------------------------------------------------------------- */
 
 void Molecule::nspecial_read(int flag, char *line)
 {
   int tmp,c1,c2,c3;
 
   if (flag == 0) maxspecial = 0;
 
   for (int i = 0; i < natoms; i++) {
     readline(line);
     if (i == 0) {
       int nwords = atom->count_words(line);
       if (nwords != 4) 
         error->all(FLERR,"Invalid Special Bond Counts section in "
                    "molecule file");
     }
     sscanf(line,"%d %d %d %d",&tmp,&c1,&c2,&c3);
 
     if (flag) {
       nspecial[i][0] = c1;
       nspecial[i][1] = c1+c2;
       nspecial[i][2] = c1+c2+c3;
     } else maxspecial = MAX(maxspecial,c1+c2+c3);
   }
 }
 
 /* ----------------------------------------------------------------------
    read special bond indices from file
 ------------------------------------------------------------------------- */
 
 void Molecule::special_read(char *line)
 {
   int m,nwords;
   char **words = new char*[maxspecial+1];
 
   for (int i = 0; i < natoms; i++) {
     readline(line);
     nwords = parse(line,words,maxspecial+1);
     if (nwords != nspecial[i][2]+1)
       error->all(FLERR,"Molecule file special list "
 		 "does not match special count");
 
     for (m = 1; m < nwords; m++) {
       special[i][m-1] = ATOTAGINT(words[m]);
       if (special[i][m-1] <= 0 || special[i][m-1] > natoms ||
 	  special[i][m-1] == i+1)
 	error->all(FLERR,"Invalid special atom index in molecule file");
     }
   }
 
   delete [] words;
 }
 
 /* ----------------------------------------------------------------------
    auto generate special bond info
 ------------------------------------------------------------------------- */
 
 void Molecule::special_generate()
 {
   int newton_bond = force->newton_bond;
   tagint atom1,atom2;
   int count[natoms];
 
   for (int i = 0; i < natoms; i++) count[i] = 0;
 
   // 1-2 neighbors
 
   if (newton_bond) {
     for (int i = 0; i < natoms; i++) {
       for (int j = 0; j < num_bond[i]; j++) {
         atom1 = i;
         atom2 = bond_atom[i][j]-1;
         nspecial[i][0]++;
         nspecial[atom2][0]++;
         if (count[i] >= maxspecial || count[atom2] >= maxspecial)
           error->one(FLERR,"Molecule auto special bond generation overflow");
         special[i][count[i]++] = atom2 + 1;
         special[atom2][count[atom2]++] = i + 1;
       } 
     }	
   } else {
     for (int i = 0; i < natoms; i++) {
       nspecial[i][0] = num_bond[i];
       for (int j = 0; j < num_bond[i]; j++) {
         atom1 = i;
         atom2 = bond_atom[i][j];
         if (count[atom1] >= maxspecial)
           error->one(FLERR,"");
         special[i][count[atom1]++] = atom2;  
       }
     }
   }
 
   // 1-3 neighbors with no duplicates
 
   for (int i = 0; i < natoms; i++) nspecial[i][1] = nspecial[i][0];
 
   int dedup;
   for (int i = 0; i < natoms; i++) {
     for (int m = 0; m < nspecial[i][0]; m++) {
       for (int j = 0; j < nspecial[special[i][m]-1][0]; j++) {
         dedup = 0;
         for (int k =0; k < count[i]; k++) {
           if (special[special[i][m]-1][j] == special[i][k] ||
               special[special[i][m]-1][j] == i+1) {
             dedup = 1;
           }
         }
         if (!dedup) {
           if (count[i] >= maxspecial)
             error->one(FLERR,"");
           special[i][count[i]++] = special[special[i][m]-1][j];
           nspecial[i][1]++;
         }  
       }
     }  
   }
 
   // 1-4 neighbors with no duplicates
 
   for (int i = 0; i < natoms; i++) nspecial[i][2] = nspecial[i][1];
   
   for (int i = 0; i < natoms; i++) {
     for (int m = nspecial[i][0]; m < nspecial[i][1]; m++) {
       for (int j = 0; j < nspecial[special[i][m]-1][0]; j++) {
         dedup = 0;
         for (int k =0; k < count[i]; k++) {
           if (special[special[i][m]-1][j] == special[i][k] ||
               special[special[i][m]-1][j] == i+1) {
             dedup = 1;
           }
         }
         if (!dedup) {
           if (count[i] >= maxspecial)
             error->one(FLERR,"");
           special[i][count[i]++] = special[special[i][m]-1][j];
           nspecial[i][2]++;
         }  
       }
     }  
   }
 }
 
 /* ----------------------------------------------------------------------
    read SHAKE flags from file
 ------------------------------------------------------------------------- */
 
 void Molecule::shakeflag_read(char *line)
 {
   int tmp;
   for (int i = 0; i < natoms; i++) {
     readline(line);
     sscanf(line,"%d %d",&tmp,&shake_flag[i]);
   }
 
   for (int i = 0; i < natoms; i++)
     if (shake_flag[i] < 0 || shake_flag[i] > 4) 
       error->all(FLERR,"Invalid shake flag in molecule file");
 }
 
 /* ----------------------------------------------------------------------
    read SHAKE atom info from file
 ------------------------------------------------------------------------- */
 
 void Molecule::shakeatom_read(char *line)
 {
   int tmp;
   for (int i = 0; i < natoms; i++) {
     readline(line);
     if (shake_flag[i] == 1)
       sscanf(line,"%d " TAGINT_FORMAT " " TAGINT_FORMAT " " TAGINT_FORMAT,
              &tmp,&shake_atom[i][0],&shake_atom[i][1],&shake_atom[i][2]);
     else if (shake_flag[i] == 2)
       sscanf(line,"%d " TAGINT_FORMAT " " TAGINT_FORMAT,
              &tmp,&shake_atom[i][0],&shake_atom[i][1]);
     else if (shake_flag[i] == 3)
       sscanf(line,"%d " TAGINT_FORMAT " " TAGINT_FORMAT " " TAGINT_FORMAT,
              &tmp,&shake_atom[i][0],&shake_atom[i][1],&shake_atom[i][2]);
     else if (shake_flag[i] == 4)
       sscanf(line,"%d " TAGINT_FORMAT " " TAGINT_FORMAT " " 
              TAGINT_FORMAT " " TAGINT_FORMAT,
              &tmp,&shake_atom[i][0],&shake_atom[i][1],
              &shake_atom[i][2],&shake_atom[i][3]);
   }
 
   for (int i = 0; i < natoms; i++) {
     int m = shake_flag[i];
     if (m == 1) m = 3;
     for (int j = 0; j < m; j++)
       if (shake_atom[i][j] <= 0 || shake_atom[i][j] > natoms)
         error->all(FLERR,"Invalid shake atom in molecule file");
   }
 }
 
 /* ----------------------------------------------------------------------
    read SHAKE bond type info from file
 ------------------------------------------------------------------------- */
 
 void Molecule::shaketype_read(char *line)
 {
   int tmp;
   for (int i = 0; i < natoms; i++) {
     readline(line);
     if (shake_flag[i] == 1)
       sscanf(line,"%d %d %d %d",&tmp,
              &shake_type[i][0],&shake_type[i][1],&shake_type[i][2]);
     else if (shake_flag[i] == 2)
       sscanf(line,"%d %d",&tmp,&shake_type[i][0]);
     else if (shake_flag[i] == 3)
       sscanf(line,"%d %d %d",&tmp,&shake_type[i][0],&shake_type[i][1]);
     else if (shake_flag[i] == 4)
       sscanf(line,"%d %d %d %d",&tmp,
              &shake_type[i][0],&shake_type[i][1],&shake_type[i][2]);
   }
 
   for (int i = 0; i < natoms; i++) {
     int m = shake_flag[i];
     if (m == 1) m = 3;
     for (int j = 0; j < m-1; j++)
       if (shake_type[i][j] <= 0)
         error->all(FLERR,"Invalid shake bond type in molecule file");
     if (shake_flag[i] == 1)
       if (shake_type[i][2] <= 0)
         error->all(FLERR,"Invalid shake angle type in molecule file");
   }
 }
 
 /* ----------------------------------------------------------------------
    error check molecule attributes and topology against system settings
    flag = 0, just check this molecule
    flag = 1, check all molecules in set, this is 1st molecule in set
 ------------------------------------------------------------------------- */
 
 void Molecule::check_attributes(int flag)
 {
   int n = 1;
   if (flag) n = nset;
   int imol = atom->find_molecule(id);
 
   for (int i = imol; i < imol+n; i++) {
     Molecule *onemol = atom->molecules[imol];
     
     // check per-atom attributes of molecule
     // warn if not a match
 
     int mismatch = 0;
     if (onemol->qflag && !atom->q_flag) mismatch = 1;
     if (onemol->radiusflag && !atom->radius_flag) mismatch = 1;
     if (onemol->rmassflag && !atom->rmass_flag) mismatch = 1;
 
     if (mismatch && me == 0) 
       error->warning(FLERR,
                      "Molecule attributes do not match system attributes");
 
     // for all atom styles, check nbondtype,etc
 
     mismatch = 0;
     if (atom->nbondtypes < onemol->nbondtypes) mismatch = 1;
     if (atom->nangletypes < onemol->nangletypes) mismatch = 1;
     if (atom->ndihedraltypes < onemol->ndihedraltypes) mismatch = 1;
     if (atom->nimpropertypes < onemol->nimpropertypes) mismatch = 1;
 
     if (mismatch) 
       error->all(FLERR,"Molecule topology type exceeds system topology type");
 
     // for molecular atom styles, check bond_per_atom,etc + maxspecial
     // do not check for atom style template, since nothing stored per atom
 
     if (atom->molecular == 1) {
       if (atom->avec->bonds_allow &&
           atom->bond_per_atom < onemol->bond_per_atom) mismatch = 1;
       if (atom->avec->angles_allow &&
           atom->angle_per_atom < onemol->angle_per_atom) mismatch = 1;
       if (atom->avec->dihedrals_allow &&
           atom->dihedral_per_atom < onemol->dihedral_per_atom) mismatch = 1;
       if (atom->avec->impropers_allow &&
           atom->improper_per_atom < onemol->improper_per_atom) mismatch = 1;
       if (atom->maxspecial < onemol->maxspecial) mismatch = 1;
 
       if (mismatch) 
         error->all(FLERR,"Molecule toplogy/atom exceeds system topology/atom");
     }
 
     // warn if molecule topology defined but no special settings
 
     if (onemol->bondflag && !onemol->specialflag) 
       if (me == 0) error->warning(FLERR,"Molecule has bond topology "
                                   "but no special bond settings");
   }
 }
 
 /* ----------------------------------------------------------------------
    init all data structures to empty
 ------------------------------------------------------------------------- */
 
 void Molecule::initialize()
 {
   natoms = 0;
   nbonds = nangles = ndihedrals = nimpropers = 0;
   ntypes = 0;
   nbondtypes = nangletypes = ndihedraltypes = nimpropertypes = 0;
 
   bond_per_atom = angle_per_atom = dihedral_per_atom = improper_per_atom = 0;
   maxspecial = 0;
 
   xflag = typeflag = qflag = radiusflag = rmassflag = 0;
   bondflag = angleflag = dihedralflag = improperflag = 0;
   nspecialflag = specialflag = 0;
   shakeflag = shakeflagflag = shakeatomflag = shaketypeflag = 0;
 
   centerflag = massflag = comflag = inertiaflag = 0;
   tag_require = 0;
 
   x = NULL;
   type = NULL;
   q = NULL;
   radius = NULL;
   rmass = NULL;
 
   num_bond = NULL;
   bond_type = NULL;
   bond_atom = NULL;
 
   num_angle = NULL;
   angle_type = NULL;
   angle_atom1 = angle_atom2 = angle_atom3 = NULL;
 
   num_dihedral = NULL;
   dihedral_type = NULL;
   dihedral_atom1 = dihedral_atom2 = dihedral_atom3 = dihedral_atom4 = NULL;
 
   num_improper = NULL;
   improper_type = NULL;
   improper_atom1 = improper_atom2 = improper_atom3 = improper_atom4 = NULL;
 
   nspecial = NULL;
   special = NULL;
 
   shake_flag = NULL;
   shake_atom = NULL;
   shake_type = NULL;
 
   dx = NULL;
   dxcom = NULL;
   dxbody = NULL;
 }
 
 /* ----------------------------------------------------------------------
    allocate all data structures
    also initialize values for data structures that are always allocated
 ------------------------------------------------------------------------- */
 
 void Molecule::allocate()
 {
   if (xflag) memory->create(x,natoms,3,"molecule:x");
   if (typeflag) memory->create(type,natoms,"molecule:type");
   if (qflag) memory->create(q,natoms,"molecule:q");
   if (radiusflag) memory->create(radius,natoms,"molecule:radius");
   if (rmassflag) memory->create(rmass,natoms,"molecule:rmass");
 
   // always allocate num_bond,num_angle,etc and special+nspecial
   // even if not in molecule file, initialize to 0
   // this is so methods that use these arrays don't have to check they exist
 
   memory->create(num_bond,natoms,"molecule:num_bond");
   for (int i = 0; i < natoms; i++) num_bond[i] = 0;
   memory->create(num_angle,natoms,"molecule:num_angle");
   for (int i = 0; i < natoms; i++) num_angle[i] = 0;
   memory->create(num_dihedral,natoms,"molecule:num_dihedral");
   for (int i = 0; i < natoms; i++) num_dihedral[i] = 0;
   memory->create(num_improper,natoms,"molecule:num_improper");
   for (int i = 0; i < natoms; i++) num_improper[i] = 0;
 
   memory->create(special,natoms,maxspecial,"molecule:special");
 
   memory->create(nspecial,natoms,3,"molecule:nspecial");
   for (int i = 0; i < natoms; i++)
     nspecial[i][0] = nspecial[i][1] = nspecial[i][2] = 0;
 
   if (bondflag) {
     memory->create(bond_type,natoms,bond_per_atom,
 		   "molecule:bond_type");
     memory->create(bond_atom,natoms,bond_per_atom,
 		   "molecule:bond_atom");
   }
 
   if (angleflag) {
     memory->create(angle_type,natoms,angle_per_atom,
 		   "molecule:angle_type");
     memory->create(angle_atom1,natoms,angle_per_atom,
 		   "molecule:angle_atom1");
     memory->create(angle_atom2,natoms,angle_per_atom,
 		   "molecule:angle_atom2");
     memory->create(angle_atom3,natoms,angle_per_atom,
 		   "molecule:angle_atom3");
   }
 
   if (dihedralflag) {
     memory->create(dihedral_type,natoms,dihedral_per_atom,
 		   "molecule:dihedral_type");
     memory->create(dihedral_atom1,natoms,dihedral_per_atom,
 		   "molecule:dihedral_atom1");
     memory->create(dihedral_atom2,natoms,dihedral_per_atom,
 		   "molecule:dihedral_atom2");
     memory->create(dihedral_atom3,natoms,dihedral_per_atom,
 		   "molecule:dihedral_atom3");
     memory->create(dihedral_atom4,natoms,dihedral_per_atom,
 		   "molecule:dihedral_atom4");
   }
 
   if (improperflag) {
     memory->create(improper_type,natoms,improper_per_atom,
 		   "molecule:improper_type");
     memory->create(improper_atom1,natoms,improper_per_atom,
 		   "molecule:improper_atom1");
     memory->create(improper_atom2,natoms,improper_per_atom,
 		   "molecule:improper_atom2");
     memory->create(improper_atom3,natoms,improper_per_atom,
 		   "molecule:improper_atom3");
     memory->create(improper_atom4,natoms,improper_per_atom,
 		   "molecule:improper_atom4");
   }
 
   if (shakeflag) {
     memory->create(shake_flag,natoms,"molecule:shake_flag");
     memory->create(shake_atom,natoms,4,"molecule:shake_flag");
     memory->create(shake_type,natoms,3,"molecule:shake_flag");
   }
 }
 
 /* ----------------------------------------------------------------------
    deallocate all data structures
 ------------------------------------------------------------------------- */
 
 void Molecule::deallocate()
 {
   memory->destroy(x);
   memory->destroy(type);
   memory->destroy(q);
   memory->destroy(radius);
   memory->destroy(rmass);
   
   memory->destroy(num_bond);
   memory->destroy(bond_type);
   memory->destroy(bond_atom);
   
   memory->destroy(num_angle);
   memory->destroy(angle_type);
   memory->destroy(angle_atom1);
   memory->destroy(angle_atom2);
   memory->destroy(angle_atom3);
   
   memory->destroy(num_dihedral);
   memory->destroy(dihedral_type);
   memory->destroy(dihedral_atom1);
   memory->destroy(dihedral_atom2);
   memory->destroy(dihedral_atom3);
   memory->destroy(dihedral_atom4);
   
   memory->destroy(num_improper);
   memory->destroy(improper_type);
   memory->destroy(improper_atom1);
   memory->destroy(improper_atom2);
   memory->destroy(improper_atom3);
   memory->destroy(improper_atom4);
 
   memory->destroy(nspecial);
   memory->destroy(special);
 
   memory->destroy(shake_flag);
   memory->destroy(shake_atom);
   memory->destroy(shake_type);
 
   memory->destroy(dx);
   memory->destroy(dxcom);
   memory->destroy(dxbody);
 }
 
 /* ----------------------------------------------------------------------
    open molecule file
 ------------------------------------------------------------------------- */
 
 void Molecule::open(char *file)
 {
   fp = fopen(file,"r");
   if (fp == NULL) {
     char str[128];
     sprintf(str,"Cannot open molecule file %s",file);
     error->one(FLERR,str);
   }
 }
 
 /* ----------------------------------------------------------------------
    read and bcast a line
 ------------------------------------------------------------------------- */
 
 void Molecule::readline(char *line)
 {
   int n;
   if (me == 0) {
     if (fgets(line,MAXLINE,fp) == NULL) n = 0;
     else n = strlen(line) + 1;
   }
   MPI_Bcast(&n,1,MPI_INT,0,world);
   if (n == 0) error->all(FLERR,"Unexpected end of molecule file");
   MPI_Bcast(line,n,MPI_CHAR,0,world);
 }
 
 /* ----------------------------------------------------------------------
    extract keyword from line
    flag = 0, read and bcast line
    flag = 1, line has already been read
 ------------------------------------------------------------------------- */
 
 void Molecule::parse_keyword(int flag, char *line, char *keyword)
 {
   if (flag) {
 
     // read upto non-blank line plus 1 following line
     // eof is set to 1 if any read hits end-of-file
 
     int eof = 0;
     if (me == 0) {
       if (fgets(line,MAXLINE,fp) == NULL) eof = 1;
       while (eof == 0 && strspn(line," \t\n\r") == strlen(line)) {
 	if (fgets(line,MAXLINE,fp) == NULL) eof = 1;
       }
       if (fgets(keyword,MAXLINE,fp) == NULL) eof = 1;
     }
 
     // if eof, set keyword empty and return
 
     MPI_Bcast(&eof,1,MPI_INT,0,world);
     if (eof) {
       keyword[0] = '\0';
       return;
     }
 
     // bcast keyword line to all procs
 
     int n;
     if (me == 0) n = strlen(line) + 1;
     MPI_Bcast(&n,1,MPI_INT,0,world);
     MPI_Bcast(line,n,MPI_CHAR,0,world);
   }
 
   // copy non-whitespace portion of line into keyword
 
   int start = strspn(line," \t\n\r");
   int stop = strlen(line) - 1;
   while (line[stop] == ' ' || line[stop] == '\t'
          || line[stop] == '\n' || line[stop] == '\r') stop--;
   line[stop+1] = '\0';
   strcpy(keyword,&line[start]);
 }
 
 /* ----------------------------------------------------------------------
    skip N lines of file
 ------------------------------------------------------------------------- */
 
 void Molecule::skip_lines(int n, char *line)
 {
   for (int i = 0; i < n; i++) readline(line);
 }
 
 /* ----------------------------------------------------------------------
    parse line into words separated by whitespace
    return # of words
    max = max pointers storable in words
 ------------------------------------------------------------------------- */
 
 int Molecule::parse(char *line, char **words, int max)
 {
   char *ptr;
 
   int nwords = 0;
   words[nwords++] = strtok(line," \t\n\r\f");
 
   while ((ptr = strtok(NULL," \t\n\r\f"))) {
     if (nwords < max) words[nwords] = ptr;
     nwords++;
   }
 
   return nwords;
 }
 
 /* ----------------------------------------------------------------------
    proc 0 prints molecule params
 ------------------------------------------------------------------------- */
 
 /*
 
 void Molecule::print()
 {
   printf("MOLECULE %s\n",id);
   printf("  %d natoms\n",natoms);
   if (nbonds) printf("  %d nbonds\n",nbonds);
   if (nangles) printf("  %d nangles\n",nangles);
   if (ndihedrals) printf("  %d ndihedrals\n",ndihedrals);
   if (nimpropers) printf("  %d nimpropers\n",nimpropers);
 
   if (xflag) {
     printf(  "Coords:\n");
     for (int i = 0; i < natoms; i++)
       printf("    %d %g %g %g\n",i+1,x[i][0],x[i][1],x[i][2]);
   }
   if (typeflag) {
     printf(  "Types:\n");
     for (int i = 0; i < natoms; i++)
       printf("    %d %d\n",i+1,type[i]);
   }
   if (qflag) {
     printf(  "Charges:\n");
     for (int i = 0; i < natoms; i++)
       printf("    %d %g\n",i+1,q[i]);
   }
   if (radiusflag) {
     printf(  "Radii:\n");
     for (int i = 0; i < natoms; i++)
       printf("    %d %g\n",i+1,radius[i]);
   }
   if (rmassflag) {
     printf(  "Masses:\n");
     for (int i = 0; i < natoms; i++)
       printf("    %d %g\n",i+1,rmass[i]);
   }
       
   if (bondflag) {
     printf(  "Bonds:\n");
     for (int i = 0; i < natoms; i++) {
       printf("    %d %d\n",i+1,num_bond[i]);
       for (int j = 0; j < num_bond[i]; j++)
         printf("      %d %d %d %d\n",j+1,bond_type[i][j],i+1,bond_atom[i][j]);
     }
   }
   if (angleflag) {
     printf(  "Angles:\n");
     for (int i = 0; i < natoms; i++) {
       printf("    %d %d\n",i+1,num_angle[i]);
       for (int j = 0; j < num_angle[i]; j++)
         printf("      %d %d %d %d %d\n",
                j+1,angle_type[i][j],
                angle_atom1[i][j],angle_atom2[i][j],angle_atom3[i][j]);
     }
   }
   if (dihedralflag) {
     printf(  "Dihedrals:\n");
     for (int i = 0; i < natoms; i++) {
       printf("    %d %d\n",i+1,num_dihedral[i]);
       for (int j = 0; j < num_dihedral[i]; j++)
         printf("      %d %d %d %d %d %d\n",
                j+1,dihedral_type[i][j],
                dihedral_atom1[i][j],dihedral_atom2[i][j],
                dihedral_atom3[i][j],dihedral_atom4[i][j]);
     }
   }
   if (improperflag) {
     printf(  "Impropers:\n");
     for (int i = 0; i < natoms; i++) {
       printf("    %d %d\n",i+1,num_improper[i]);
       for (int j = 0; j < num_improper[i]; j++)
         printf("      %d %d %d %d %d %d\n",
                j+1,improper_type[i][j],
                improper_atom1[i][j],improper_atom2[i][j],
                improper_atom3[i][j],improper_atom4[i][j]);
     }
   }
 
   if (specialflag) {
     printf(  "Special neighs:\n");
     for (int i = 0; i < natoms; i++) {
       printf("    %d %d %d %d\n",i+1,
              nspecial[i][0],nspecial[i][1]-nspecial[i][0],
              nspecial[i][2]-nspecial[i][1]);
       printf("      ");
       for (int j = 0; j < nspecial[i][2]; j++)
         printf(" %d",special[i][j]);
       printf("\n");
     }
   }
 }
 
 */