lammps/src/compute_variable_atom.cpp

97 lines
2.6 KiB
C++

/* ----------------------------------------------------------------------
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 "string.h"
#include "compute_variable_atom.h"
#include "atom.h"
#include "input.h"
#include "variable.h"
#include "memory.h"
#include "error.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
ComputeVariableAtom::ComputeVariableAtom(LAMMPS *lmp, int narg, char **arg) :
Compute(lmp, narg, arg)
{
if (narg != 4) error->all("Illegal compute variable/atom command");
// store variable name
int n = strlen(arg[3]) + 1;
varname = new char[n];
strcpy(varname,arg[3]);
peratom_flag = 1;
size_peratom = 0;
nmax = 0;
result = NULL;
}
/* ---------------------------------------------------------------------- */
ComputeVariableAtom::~ComputeVariableAtom()
{
delete [] varname;
memory->sfree(result);
}
/* ---------------------------------------------------------------------- */
void ComputeVariableAtom::init()
{
// set ivariable used by this compute
ivariable = input->variable->find(varname);
if (ivariable < 0)
error->all("Could not find compute variable name");
// test if variable of correct ATOM type
}
/* ---------------------------------------------------------------------- */
void ComputeVariableAtom::compute_peratom()
{
// grow result array if necessary
if (atom->nlocal > nmax) {
memory->sfree(result);
nmax = atom->nmax;
result = (double *) memory->smalloc(nmax*sizeof(double),
"compute/variable/atom:result");
scalar_atom = result;
}
// parse variable once to create parse tree
// evaluate tree for all atoms, will be zero for atoms not in group
// free parse tree memory stored by Variable
input->variable->build_parse_tree(ivariable);
input->variable->evaluate_parse_tree(igroup,result);
input->variable->free_parse_tree();
}
/* ----------------------------------------------------------------------
memory usage of local atom-based array
------------------------------------------------------------------------- */
int ComputeVariableAtom::memory_usage()
{
int bytes = nmax * sizeof(double);
return bytes;
}