50 lines
1.4 KiB
C++
50 lines
1.4 KiB
C++
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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http://lammps.sandia.gov, Sandia National Laboratories
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Steve Plimpton, sjplimp@sandia.gov
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Copyright (2003) Sandia Corporation. Under the terms of Contract
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DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
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certain rights in this software. This software is distributed under
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the GNU General Public License.
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See the README file in the top-level LAMMPS directory.
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------------------------------------------------------------------------- */
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#include "compute_gyration.h"
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#include "update.h"
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#include "group.h"
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#include "error.h"
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using namespace LAMMPS_NS;
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/* ---------------------------------------------------------------------- */
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ComputeGyration::ComputeGyration(LAMMPS *lmp, int narg, char **arg) :
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Compute(lmp, narg, arg)
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{
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if (narg != 3) error->all("Illegal compute gyration command");
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scalar_flag = 1;
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extscalar = 0;
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}
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/* ---------------------------------------------------------------------- */
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void ComputeGyration::init()
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{
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masstotal = group->mass(igroup);
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}
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/* ---------------------------------------------------------------------- */
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double ComputeGyration::compute_scalar()
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{
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invoked_scalar = update->ntimestep;
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double xcm[3];
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group->xcm(igroup,masstotal,xcm);
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scalar = group->gyration(igroup,masstotal,xcm);
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return scalar;
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}
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