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fix_smd_adjust_dt.cpp
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Mon, Nov 11, 17:44

fix_smd_adjust_dt.cpp
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/* ----------------------------------------------------------------------
*
* *** Smooth Mach Dynamics ***
*
* This file is part of the USER-SMD package for LAMMPS.
* Copyright (2014) Georg C. Ganzenmueller, georg.ganzenmueller@emi.fhg.de
* Fraunhofer Ernst-Mach Institute for High-Speed Dynamics, EMI,
* Eckerstrasse 4, D-79104 Freiburg i.Br, Germany.
*
* ----------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
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 <math.h>
#include <stdlib.h>
#include <string.h>
#include "fix_smd_adjust_dt.h"
#include "atom.h"
#include "update.h"
#include "integrate.h"
#include "domain.h"
#include "lattice.h"
#include "force.h"
#include "pair.h"
#include "modify.h"
#include "fix.h"
#include "output.h"
#include "dump.h"
#include "comm.h"
#include "error.h"
using namespace LAMMPS_NS;
using namespace FixConst;
#define BIG 1.0e20
/* ---------------------------------------------------------------------- */
FixSMDTlsphDtReset::FixSMDTlsphDtReset(LAMMPS *lmp, int narg, char **arg) :
Fix(lmp, narg, arg) {
if (narg != 4)
error->all(FLERR, "Illegal fix smd/adjust_dt command");
// set time_depend, else elapsed time accumulation can be messed up
time_depend = 1;
scalar_flag = 1;
vector_flag = 1;
size_vector = 2;
global_freq = 1;
extscalar = 0;
extvector = 0;
restart_global = 1; // this fix stores global (i.e., not per-atom) info: elaspsed time
safety_factor = atof(arg[3]);
// initializations
t_elapsed = 0.0;
}
/* ---------------------------------------------------------------------- */
int FixSMDTlsphDtReset::setmask() {
int mask = 0;
mask |= INITIAL_INTEGRATE;
mask |= END_OF_STEP;
return mask;
}
/* ---------------------------------------------------------------------- */
void FixSMDTlsphDtReset::init() {
dt = update->dt;
}
/* ---------------------------------------------------------------------- */
void FixSMDTlsphDtReset::setup(int vflag) {
end_of_step();
}
/* ---------------------------------------------------------------------- */
void FixSMDTlsphDtReset::initial_integrate(int vflag) {
//printf("in adjust_dt: dt = %20.10f\n", update->dt);
t_elapsed += update->dt;
}
/* ---------------------------------------------------------------------- */
void FixSMDTlsphDtReset::end_of_step() {
double dtmin = BIG;
int itmp = 0;
/*
* extract minimum CFL timestep from TLSPH and ULSPH pair styles
*/
double *dtCFL_TLSPH = (double *) force->pair->extract("smd/tlsph/dtCFL_ptr", itmp);
double *dtCFL_ULSPH = (double *) force->pair->extract("smd/ulsph/dtCFL_ptr", itmp);
double *dt_TRI = (double *) force->pair->extract("smd/tri_surface/stable_time_increment_ptr", itmp);
double *dt_HERTZ = (double *) force->pair->extract("smd/hertz/stable_time_increment_ptr", itmp);
double *dt_PERI_IPMB = (double *) force->pair->extract("smd/peri_ipmb/stable_time_increment_ptr", itmp);
if ((dtCFL_TLSPH == NULL) && (dtCFL_ULSPH == NULL) && (dt_TRI == NULL) && (dt_HERTZ == NULL)
&& (dt_PERI_IPMB == NULL)) {
error->all(FLERR, "fix smd/adjust_dt failed to access a valid dtCFL");
}
if (dtCFL_TLSPH != NULL) {
dtmin = MIN(dtmin, *dtCFL_TLSPH);
}
if (dtCFL_ULSPH != NULL) {
dtmin = MIN(dtmin, *dtCFL_ULSPH);
}
if (dt_TRI != NULL) {
dtmin = MIN(dtmin, *dt_TRI);
}
if (dt_HERTZ != NULL) {
dtmin = MIN(dtmin, *dt_HERTZ);
}
if (dt_PERI_IPMB != NULL) {
dtmin = MIN(dtmin, *dt_PERI_IPMB);
}
// double **v = atom->v;
// double **f = atom->f;
// double *rmass = atom->rmass;
// double *radius = atom->radius;
// int *mask = atom->mask;
// int nlocal = atom->nlocal;
// double dtv, dtf, dtsq;
// double vsq, fsq, massinv, xmax;
// double delx, dely, delz, delr;
// for (int i = 0; i < nlocal; i++) {
// if (mask[i] & groupbit) {
// xmax = 0.005 * radius[i];
// massinv = 1.0 / rmass[i];
// vsq = v[i][0] * v[i][0] + v[i][1] * v[i][1] + v[i][2] * v[i][2];
// fsq = f[i][0] * f[i][0] + f[i][1] * f[i][1] + f[i][2] * f[i][2];
// dtv = dtf = BIG;
// if (vsq > 0.0)
// dtv = xmax / sqrt(vsq);
// if (fsq > 0.0)
// dtf = sqrt(2.0 * xmax / (sqrt(fsq) * massinv));
// dt = MIN(dtv, dtf);
// dtmin = MIN(dtmin, dt);
// dtsq = dt * dt;
// delx = dt * v[i][0] + 0.5 * dtsq * massinv * f[i][0];
// dely = dt * v[i][1] + 0.5 * dtsq * massinv * f[i][1];
// delz = dt * v[i][2] + 0.5 * dtsq * massinv * f[i][2];
// delr = sqrt(delx * delx + dely * dely + delz * delz);
// if (delr > xmax)
// dt *= xmax / delr;
// dtmin = MIN(dtmin, dt);
//
//// xmax = 0.05 * radius[i];
//// massinv = 1.0 / rmass[i];
//// fsq = f[i][0] * f[i][0] + f[i][1] * f[i][1] + f[i][2] * f[i][2];
//// dtf = BIG;
//// if (fsq > 0.0)
//// dtf = sqrt(2.0 * xmax / (sqrt(fsq) * massinv));
//// dtmin = MIN(dtmin, dtf);
// }
// }
dtmin *= safety_factor; // apply safety factor
MPI_Allreduce(&dtmin, &dt, 1, MPI_DOUBLE, MPI_MIN, world);
if (update->ntimestep == 0) {
dt = 1.0e-16;
}
//printf("dtmin is now: %f, dt is now%f\n", dtmin, dt);
update->dt = dt;
if (force->pair)
force->pair->reset_dt();
for (int i = 0; i < modify->nfix; i++)
modify->fix[i]->reset_dt();
}
/* ---------------------------------------------------------------------- */
double FixSMDTlsphDtReset::compute_scalar() {
return t_elapsed;
}
/* ----------------------------------------------------------------------
pack entire state of Fix into one write
------------------------------------------------------------------------- */
void FixSMDTlsphDtReset::write_restart(FILE *fp) {
int n = 0;
double list[1];
list[n++] = t_elapsed;
if (comm->me == 0) {
int size = n * sizeof(double);
fwrite(&size, sizeof(int), 1, fp);
fwrite(list, sizeof(double), n, fp);
}
}
/* ----------------------------------------------------------------------
use state info from restart file to restart the Fix
------------------------------------------------------------------------- */
void FixSMDTlsphDtReset::restart(char *buf) {
int n = 0;
double *list = (double *) buf;
t_elapsed = list[n++];
}

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