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fix_nh_cuda.cpp
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Mon, Apr 28, 19:33

fix_nh_cuda.cpp
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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: Mark Stevens (SNL), Aidan Thompson (SNL)
------------------------------------------------------------------------- */
#include <cstring>
#include <cstdlib>
#include <cmath>
#include "fix_nh_cuda.h"
#include "atom.h"
#include "force.h"
#include "comm.h"
#include "modify.h"
#include "fix_deform.h"
#include "compute.h"
#include "kspace.h"
#include "update.h"
#include "respa.h"
#include "domain.h"
#include "memory.h"
#include "error.h"
#include "math_extra.h"
#include "cuda.h"
#include "fix_nh_cuda_cu.h"
#include "cuda_modify_flags.h"
using namespace LAMMPS_NS;
#define MIN(A,B) ((A) < (B)) ? (A) : (B)
#define MAX(A,B) ((A) > (B)) ? (A) : (B)
enum{NOBIAS,BIAS};
enum{NONE,XYZ,XY,YZ,XZ};
enum{ISO,ANISO,TRICLINIC};
/* ----------------------------------------------------------------------
NVT,NPH,NPT integrators for improved Nose-Hoover equations of motion
---------------------------------------------------------------------- */
FixNHCuda::FixNHCuda(LAMMPS *lmp, int narg, char **arg) : Fix(lmp, narg, arg)
{
cuda = lmp->cuda;
if(cuda == NULL)
error->all("You cannot use a /cuda class, without activating 'cuda' acceleration. Provide '-c on' as command-line argument to LAMMPS..");
if (narg < 4) error->all("Illegal fix nvt/npt/nph command");
restart_global = 1;
time_integrate = 1;
scalar_flag = 1;
vector_flag = 1;
global_freq = 1;
extscalar = 1;
extvector = 0;
triggerneighsq = -1;
// default values
pcouple = NONE;
drag = 0.0;
allremap = 1;
mtchain = mpchain = 3;
nc_tchain = nc_pchain = 1;
mtk_flag = 1;
deviatoric_flag = 0;
nreset_h0 = 0;
// Used by FixNVTSllod to preserve non-default value
mtchain_default_flag = 1;
tstat_flag = 0;
double t_period = 0.0;
double p_period[6];
for (int i = 0; i < 6; i++) {
p_start[i] = p_stop[i] = p_period[i] = 0.0;
p_flag[i] = 0;
}
// process keywords
dimension = domain->dimension;
int iarg = 3;
while (iarg < narg) {
if (strcmp(arg[iarg],"temp") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
tstat_flag = 1;
t_start = atof(arg[iarg+1]);
t_stop = atof(arg[iarg+2]);
t_period = atof(arg[iarg+3]);
if (t_start < 0.0 || t_stop <= 0.0)
error->all("Target T for fix nvt/npt/nph cannot be 0.0");
iarg += 4;
} else if (strcmp(arg[iarg],"iso") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
pcouple = XYZ;
p_start[0] = p_start[1] = p_start[2] = atof(arg[iarg+1]);
p_stop[0] = p_stop[1] = p_stop[2] = atof(arg[iarg+2]);
p_period[0] = p_period[1] = p_period[2] = atof(arg[iarg+3]);
p_flag[0] = p_flag[1] = p_flag[2] = 1;
if (dimension == 2) {
p_start[2] = p_stop[2] = p_period[2] = 0.0;
p_flag[2] = 0;
}
iarg += 4;
} else if (strcmp(arg[iarg],"aniso") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
pcouple = NONE;
p_start[0] = p_start[1] = p_start[2] = atof(arg[iarg+1]);
p_stop[0] = p_stop[1] = p_stop[2] = atof(arg[iarg+2]);
p_period[0] = p_period[1] = p_period[2] = atof(arg[iarg+3]);
p_flag[0] = p_flag[1] = p_flag[2] = 1;
if (dimension == 2) {
p_start[2] = p_stop[2] = p_period[2] = 0.0;
p_flag[2] = 0;
}
iarg += 4;
} else if (strcmp(arg[iarg],"tri") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
pcouple = NONE;
p_start[0] = p_start[1] = p_start[2] = atof(arg[iarg+1]);
p_stop[0] = p_stop[1] = p_stop[2] = atof(arg[iarg+2]);
p_period[0] = p_period[1] = p_period[2] = atof(arg[iarg+3]);
p_flag[0] = p_flag[1] = p_flag[2] = 1;
p_start[3] = p_start[4] = p_start[5] = 0.0;
p_stop[3] = p_stop[4] = p_stop[5] = 0.0;
p_period[3] = p_period[4] = p_period[5] = atof(arg[iarg+3]);
p_flag[3] = p_flag[4] = p_flag[5] = 1;
if (dimension == 2) {
p_start[2] = p_stop[2] = p_period[2] = 0.0;
p_flag[2] = 0;
p_start[3] = p_stop[3] = p_period[3] = 0.0;
p_flag[3] = 0;
p_start[4] = p_stop[4] = p_period[4] = 0.0;
p_flag[4] = 0;
}
iarg += 4;
} else if (strcmp(arg[iarg],"x") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
p_start[0] = atof(arg[iarg+1]);
p_stop[0] = atof(arg[iarg+2]);
p_period[0] = atof(arg[iarg+3]);
p_flag[0] = 1;
deviatoric_flag = 1;
iarg += 4;
} else if (strcmp(arg[iarg],"y") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
p_start[1] = atof(arg[iarg+1]);
p_stop[1] = atof(arg[iarg+2]);
p_period[1] = atof(arg[iarg+3]);
p_flag[1] = 1;
deviatoric_flag = 1;
iarg += 4;
} else if (strcmp(arg[iarg],"z") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
p_start[2] = atof(arg[iarg+1]);
p_stop[2] = atof(arg[iarg+2]);
p_period[2] = atof(arg[iarg+3]);
p_flag[2] = 1;
deviatoric_flag = 1;
iarg += 4;
if (dimension == 2)
error->all("Invalid fix nvt/npt/nph command for a 2d simulation");
} else if (strcmp(arg[iarg],"yz") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
p_start[3] = atof(arg[iarg+1]);
p_stop[3] = atof(arg[iarg+2]);
p_period[3] = atof(arg[iarg+3]);
p_flag[3] = 1;
deviatoric_flag = 1;
iarg += 4;
if (dimension == 2)
error->all("Invalid fix nvt/npt/nph command for a 2d simulation");
} else if (strcmp(arg[iarg],"xz") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
p_start[4] = atof(arg[iarg+1]);
p_stop[4] = atof(arg[iarg+2]);
p_period[4] = atof(arg[iarg+3]);
p_flag[4] = 1;
deviatoric_flag = 1;
iarg += 4;
if (dimension == 2)
error->all("Invalid fix nvt/npt/nph command for a 2d simulation");
} else if (strcmp(arg[iarg],"xy") == 0) {
if (iarg+4 > narg) error->all("Illegal fix nvt/npt/nph command");
p_start[5] = atof(arg[iarg+1]);
p_stop[5] = atof(arg[iarg+2]);
p_period[5] = atof(arg[iarg+3]);
p_flag[5] = 1;
deviatoric_flag = 1;
iarg += 4;
} else if (strcmp(arg[iarg],"couple") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
if (strcmp(arg[iarg+1],"xyz") == 0) pcouple = XYZ;
else if (strcmp(arg[iarg+1],"xy") == 0) pcouple = XY;
else if (strcmp(arg[iarg+1],"yz") == 0) pcouple = YZ;
else if (strcmp(arg[iarg+1],"xz") == 0) pcouple = XZ;
else if (strcmp(arg[iarg+1],"none") == 0) pcouple = NONE;
else error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else if (strcmp(arg[iarg],"drag") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
drag = atof(arg[iarg+1]);
if (drag < 0.0) error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else if (strcmp(arg[iarg],"dilate") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
if (strcmp(arg[iarg+1],"all") == 0) allremap = 1;
else if (strcmp(arg[iarg+1],"partial") == 0) allremap = 0;
else error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else if (strcmp(arg[iarg],"tchain") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
mtchain = atoi(arg[iarg+1]);
if (mtchain < 1) error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else if (strcmp(arg[iarg],"pchain") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
mpchain = atoi(arg[iarg+1]);
if (mpchain < 0) error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else if (strcmp(arg[iarg],"mtk") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
if (strcmp(arg[iarg+1],"yes") == 0) mtk_flag = 1;
else if (strcmp(arg[iarg+1],"no") == 0) mtk_flag = 0;
else error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else if (strcmp(arg[iarg],"tloop") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
nc_tchain = atoi(arg[iarg+1]);
if (nc_tchain < 0) error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else if (strcmp(arg[iarg],"ploop") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
nc_pchain = atoi(arg[iarg+1]);
if (nc_pchain < 0) error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else if (strcmp(arg[iarg],"nreset") == 0) {
if (iarg+2 > narg) error->all("Illegal fix nvt/npt/nph command");
nreset_h0 = atoi(arg[iarg+1]);
if (nreset_h0 < 0) error->all("Illegal fix nvt/npt/nph command");
iarg += 2;
} else error->all("Illegal fix nvt/npt/nph command");
}
// error checks
if (dimension == 2 && (p_flag[2] || p_flag[3] || p_flag[4]))
error->all("Invalid fix nvt/npt/nph command for a 2d simulation");
if (dimension == 2 && (pcouple == YZ || pcouple == XZ))
error->all("Invalid fix nvt/npt/nph command for a 2d simulation");
if (pcouple == XYZ && (p_flag[0] == 0 || p_flag[1] == 0))
error->all("Invalid fix nvt/npt/nph command pressure settings");
if (pcouple == XYZ && dimension == 3 && p_flag[2] == 0)
error->all("Invalid fix nvt/npt/nph command pressure settings");
if (pcouple == XY && (p_flag[0] == 0 || p_flag[1] == 0))
error->all("Invalid fix nvt/npt/nph command pressure settings");
if (pcouple == YZ && (p_flag[1] == 0 || p_flag[2] == 0))
error->all("Invalid fix nvt/npt/nph command pressure settings");
if (pcouple == XZ && (p_flag[0] == 0 || p_flag[2] == 0))
error->all("Invalid fix nvt/npt/nph command pressure settings");
if (p_flag[0] && domain->xperiodic == 0)
error->all("Cannot use fix nvt/npt/nph on a non-periodic dimension");
if (p_flag[1] && domain->yperiodic == 0)
error->all("Cannot use fix nvt/npt/nph on a non-periodic dimension");
if (p_flag[2] && domain->zperiodic == 0)
error->all("Cannot use fix nvt/npt/nph on a non-periodic dimension");
if (p_flag[3] && domain->zperiodic == 0)
error->all("Cannot use fix nvt/npt/nph on a 2nd non-periodic dimension");
if (p_flag[4] && domain->zperiodic == 0)
error->all("Cannot use fix nvt/npt/nph on a 2nd non-periodic dimension");
if (p_flag[5] && domain->yperiodic == 0)
error->all("Cannot use fix nvt/npt/nph on a 2nd non-periodic dimension");
if (!domain->triclinic && (p_flag[3] || p_flag[4] || p_flag[5]))
error->all("Can not specify Pxy/Pxz/Pyz in "
"fix nvt/npt/nph with non-triclinic box");
if (pcouple == XYZ && dimension == 3 &&
(p_start[0] != p_start[1] || p_start[0] != p_start[2] ||
p_stop[0] != p_stop[1] || p_stop[0] != p_stop[2] ||
p_period[0] != p_period[1] || p_period[0] != p_period[2]))
error->all("Invalid fix nvt/npt/nph pressure settings");
if (pcouple == XYZ && dimension == 2 &&
(p_start[0] != p_start[1] || p_stop[0] != p_stop[1] ||
p_period[0] != p_period[1]))
error->all("Invalid fix nvt/npt/nph pressure settings");
if (pcouple == XY &&
(p_start[0] != p_start[1] || p_stop[0] != p_stop[1] ||
p_period[0] != p_period[1]))
error->all("Invalid fix nvt/npt/nph pressure settings");
if (pcouple == YZ &&
(p_start[1] != p_start[2] || p_stop[1] != p_stop[2] ||
p_period[1] != p_period[2]))
error->all("Invalid fix nvt/npt/nph pressure settings");
if (pcouple == XZ &&
(p_start[0] != p_start[2] || p_stop[0] != p_stop[2] ||
p_period[0] != p_period[2]))
error->all("Invalid fix nvt/npt/nph pressure settings");
if ((tstat_flag && t_period <= 0.0) ||
(p_flag[0] && p_period[0] <= 0.0) ||
(p_flag[1] && p_period[1] <= 0.0) ||
(p_flag[2] && p_period[2] <= 0.0) ||
(p_flag[3] && p_period[3] <= 0.0) ||
(p_flag[4] && p_period[4] <= 0.0) ||
(p_flag[5] && p_period[5] <= 0.0))
error->all("Fix nvt/npt/nph damping parameters must be > 0.0");
// set pstat_flag and box change variables
pstat_flag = 0;
for (int i = 0; i < 6; i++)
if (p_flag[i]) pstat_flag = 1;
if (pstat_flag) {
box_change = 1;
if (p_flag[0] || p_flag[1] || p_flag[2]) box_change_size = 1;
if (p_flag[3] || p_flag[4] || p_flag[5]) box_change_shape = 1;
no_change_box = 1;
if (allremap == 0) restart_pbc = 1;
}
// pstyle = TRICLINIC if any off-diagonal term is controlled -> 6 dof
// else pstyle = ISO if XYZ coupling or XY coupling in 2d -> 1 dof
// else pstyle = ANISO -> 3 dof
if (p_flag[3] || p_flag[4] || p_flag[5]) pstyle = TRICLINIC;
else if (pcouple == XYZ || (dimension == 2 && pcouple == XY)) pstyle = ISO;
else pstyle = ANISO;
// convert input periods to frequencies
t_freq = 0.0;
p_freq[0] = p_freq[1] = p_freq[2] = p_freq[3] = p_freq[4] = p_freq[5] = 0.0;
if (tstat_flag) t_freq = 1.0 / t_period;
if (p_flag[0]) p_freq[0] = 1.0 / p_period[0];
if (p_flag[1]) p_freq[1] = 1.0 / p_period[1];
if (p_flag[2]) p_freq[2] = 1.0 / p_period[2];
if (p_flag[3]) p_freq[3] = 1.0 / p_period[3];
if (p_flag[4]) p_freq[4] = 1.0 / p_period[4];
if (p_flag[5]) p_freq[5] = 1.0 / p_period[5];
// Nose/Hoover temp and pressure init
size_vector = 0;
if (tstat_flag) {
int ich;
eta = new double[mtchain];
// add one extra dummy thermostat, set to zero
eta_dot = new double[mtchain+1];
eta_dot[mtchain] = 0.0;
eta_dotdot = new double[mtchain];
for (ich = 0; ich < mtchain; ich++) {
eta[ich] = eta_dot[ich] = eta_dotdot[ich] = 0.0;
}
eta_mass = new double[mtchain];
size_vector += 2*2*mtchain;
}
if (pstat_flag) {
omega[0] = omega[1] = omega[2] = 0.0;
omega_dot[0] = omega_dot[1] = omega_dot[2] = 0.0;
omega_mass[0] = omega_mass[1] = omega_mass[2] = 0.0;
omega[3] = omega[4] = omega[5] = 0.0;
omega_dot[3] = omega_dot[4] = omega_dot[5] = 0.0;
omega_mass[3] = omega_mass[4] = omega_mass[5] = 0.0;
if (pstyle == ISO) size_vector += 2*2*1;
else if (pstyle == ANISO) size_vector += 2*2*3;
else if (pstyle == TRICLINIC) size_vector += 2*2*6;
if (mpchain) {
int ich;
etap = new double[mpchain];
// add one extra dummy thermostat, set to zero
etap_dot = new double[mpchain+1];
etap_dot[mpchain] = 0.0;
etap_dotdot = new double[mpchain];
for (ich = 0; ich < mpchain; ich++) {
etap[ich] = etap_dot[ich] =
etap_dotdot[ich] = 0.0;
}
etap_mass = new double[mpchain];
size_vector += 2*2*mpchain;
}
if (deviatoric_flag) size_vector += 1;
}
nrigid = 0;
rfix = NULL;
// initialize vol0,t0 to zero to signal uninitialized
// values then assigned in init(), if necessary
vol0 = t0 = 0.0;
}
/* ---------------------------------------------------------------------- */
FixNHCuda::~FixNHCuda()
{
delete [] rfix;
// delete temperature and pressure if fix created them
if (tflag) modify->delete_compute(id_temp);
delete [] id_temp;
if (tstat_flag) {
delete [] eta;
delete [] eta_dot;
delete [] eta_dotdot;
delete [] eta_mass;
}
if (pstat_flag) {
if (pflag) modify->delete_compute(id_press);
delete [] id_press;
if (mpchain) {
delete [] etap;
delete [] etap_dot;
delete [] etap_dotdot;
delete [] etap_mass;
}
}
}
/* ---------------------------------------------------------------------- */
int FixNHCuda::setmask()
{
int mask = 0;
mask |= INITIAL_INTEGRATE_CUDA;
mask |= FINAL_INTEGRATE_CUDA;
mask |= THERMO_ENERGY_CUDA;
//mask |= INITIAL_INTEGRATE_RESPA;
//mask |= FINAL_INTEGRATE_RESPA;
return mask;
}
/* ---------------------------------------------------------------------- */
void FixNHCuda::init()
{
// insure no conflict with fix deform
if (pstat_flag)
for (int i = 0; i < modify->nfix; i++)
if (strcmp(modify->fix[i]->style,"deform") == 0) {
int *dimflag = ((FixDeform *) modify->fix[i])->dimflag;
if ((p_flag[0] && dimflag[0]) || (p_flag[1] && dimflag[1]) ||
(p_flag[2] && dimflag[2]) || (p_flag[3] && dimflag[3]) ||
(p_flag[4] && dimflag[4]) || (p_flag[5] && dimflag[5]))
error->all("Cannot use fix npt and fix deform on "
"same component of stress tensor");
}
// set temperature and pressure ptrs
int icompute = modify->find_compute(id_temp);
if (icompute < 0)
error->all("Temperature ID for fix nvt/nph/npt does not exist");
temperature = modify->compute[icompute];
if (temperature->tempbias) which = BIAS;
else which = NOBIAS;
if (pstat_flag) {
icompute = modify->find_compute(id_press);
if (icompute < 0) error->all("Pressure ID for fix npt/nph does not exist");
pressure = modify->compute[icompute];
}
// set timesteps and frequencies
dtv = update->dt;
dtf = 0.5 * update->dt * force->ftm2v;
dthalf = 0.5 * update->dt;
dt4 = 0.25 * update->dt;
dt8 = 0.125 * update->dt;
dto = dthalf;
p_freq_max = 0.0;
if (pstat_flag) {
p_freq_max = MAX(p_freq[0],p_freq[1]);
p_freq_max = MAX(p_freq_max,p_freq[2]);
if (pstyle == TRICLINIC) {
p_freq_max = MAX(p_freq_max,p_freq[3]);
p_freq_max = MAX(p_freq_max,p_freq[4]);
p_freq_max = MAX(p_freq_max,p_freq[5]);
}
pdrag_factor = 1.0 - (update->dt * p_freq_max * drag / nc_pchain);
}
if (tstat_flag)
tdrag_factor = 1.0 - (update->dt * t_freq * drag / nc_tchain);
// tally the number of dimensions that are barostatted
// also compute the initial volume and reference cell
// set initial volume and reference cell, if not already done
if (pstat_flag) {
pdim = p_flag[0] + p_flag[1] + p_flag[2];
if (vol0 == 0.0) {
if (dimension == 3) vol0 = domain->xprd * domain->yprd * domain->zprd;
else vol0 = domain->xprd * domain->yprd;
h0_inv[0] = domain->h_inv[0];
h0_inv[1] = domain->h_inv[1];
h0_inv[2] = domain->h_inv[2];
h0_inv[3] = domain->h_inv[3];
h0_inv[4] = domain->h_inv[4];
h0_inv[5] = domain->h_inv[5];
}
}
boltz = force->boltz;
nktv2p = force->nktv2p;
if (force->kspace) kspace_flag = 1;
else kspace_flag = 0;
if (strcmp(update->integrate_style,"respa") == 0) {
nlevels_respa = ((Respa *) update->integrate)->nlevels;
step_respa = ((Respa *) update->integrate)->step;
dto = 0.5*step_respa[0];
}
// detect if any rigid fixes exist so rigid bodies move when box is remapped
// rfix[] = indices to each fix rigid
delete [] rfix;
nrigid = 0;
rfix = NULL;
for (int i = 0; i < modify->nfix; i++)
if (modify->fix[i]->rigid_flag) nrigid++;
if (nrigid) {
rfix = new int[nrigid];
nrigid = 0;
for (int i = 0; i < modify->nfix; i++)
if (modify->fix[i]->rigid_flag) rfix[nrigid++] = i;
}
triggerneighsq= cuda->shared_data.atom.triggerneighsq;
cuda->neighbor_decide_by_integrator=1;
Cuda_FixNHCuda_Init(&cuda->shared_data,dtv,dtf);
}
/* ----------------------------------------------------------------------
compute T,P before integrator starts
------------------------------------------------------------------------- */
void FixNHCuda::setup(int vflag)
{
// initialize some quantities that were not available earlier
//if (mtk_flag) mtk_factor = 1.0 + 1.0/atom->natoms;
//else mtk_factor = 1.0;
tdof = temperature->dof;
// t_target is used by compute_scalar(), even for NPH
if (tstat_flag) t_target = t_start;
else if (pstat_flag) {
// t0 = initial value for piston mass and energy conservation
// cannot be done in init() b/c temperature cannot be called there
// is b/c Modify::init() inits computes after fixes due to dof dependence
// guesstimate a unit-dependent t0 if actual T = 0.0
// if it was read in from a restart file, leave it be
if (t0 == 0.0) {
t0 = temperature->compute_scalar();
if (t0 == 0.0) {
if (strcmp(update->unit_style,"lj") == 0) t0 = 1.0;
else t0 = 300.0;
}
}
t_target = t0;
}
if (pstat_flag) compute_press_target();
t_current = temperature->compute_scalar();
if (pstat_flag) {
if (pstyle == ISO) double tmp = pressure->compute_scalar();
else pressure->compute_vector();
couple();
pressure->addstep(update->ntimestep+1);
}
// initial forces on thermostat variables
if (tstat_flag) {
eta_mass[0] = tdof * boltz * t_target / (t_freq*t_freq);
for (int ich = 1; ich < mtchain; ich++)
eta_mass[ich] = boltz * t_target / (t_freq*t_freq);
for (int ich = 1; ich < mtchain; ich++) {
eta_dotdot[ich] = (eta_mass[ich-1]*eta_dot[ich-1]*eta_dot[ich-1] -
boltz*t_target) / eta_mass[ich];
}
}
if (pstat_flag) {
double kt = boltz * t_target;
double nkt = atom->natoms * kt;
for (int i = 0; i < 3; i++)
if (p_flag[i])
omega_mass[i] = nkt/(p_freq[i]*p_freq[i]);
if (pstyle == TRICLINIC) {
for (int i = 3; i < 6; i++)
if (p_flag[i]) omega_mass[i] = nkt/(p_freq[i]*p_freq[i]);
}
// initial forces on barostat thermostat variables
if (mpchain) {
etap_mass[0] = boltz * t_target / (p_freq_max*p_freq_max);
for (int ich = 1; ich < mpchain; ich++)
etap_mass[ich] = boltz * t_target / (p_freq_max*p_freq_max);
for (int ich = 1; ich < mpchain; ich++)
etap_dotdot[ich] =
(etap_mass[ich-1]*etap_dot[ich-1]*etap_dot[ich-1] -
boltz*t_target) / etap_mass[ich];
}
// compute appropriately coupled elements of mvv_current
//if (mtk_flag) couple_ke();
}
}
/* ----------------------------------------------------------------------
1st half of Verlet update
------------------------------------------------------------------------- */
void FixNHCuda::initial_integrate(int vflag)
{
if(!temperature->cudable) cuda->downloadAll();
if(triggerneighsq!=cuda->shared_data.atom.triggerneighsq)
{
triggerneighsq= cuda->shared_data.atom.triggerneighsq;
Cuda_FixNHCuda_Init(&cuda->shared_data,dtv,dtf);
}
// update eta_press_dot
if (pstat_flag && mpchain) nhc_press_integrate();
// update eta_dot
if (tstat_flag) {
double delta = update->ntimestep - update->beginstep;
delta /= update->endstep - update->beginstep;
t_target = t_start + delta * (t_stop-t_start);
eta_mass[0] = tdof * boltz * t_target / (t_freq*t_freq);
for (int ich = 1; ich < mtchain; ich++)
eta_mass[ich] = boltz * t_target / (t_freq*t_freq);
nhc_temp_integrate();
}
// need to recompute pressure to account for change in KE
// t_current is up-to-date, but compute_temperature is not
// compute appropriately coupled elements of mvv_current
if (pstat_flag) {
if (pstyle == ISO) {
temperature->compute_scalar();
double tmp = pressure->compute_scalar();
} else {
temperature->compute_vector();
pressure->compute_vector();
}
couple();
pressure->addstep(update->ntimestep+1);
//if (mtk_flag) couple_ke();
}
if(which==NOBIAS)
{
if (pstat_flag) {
compute_press_target();
nh_omega_dot();
factor[0] = exp(-dt4*(omega_dot[0]+mtk_term2));
factor[1] = exp(-dt4*(omega_dot[1]+mtk_term2));
factor[2] = exp(-dt4*(omega_dot[2]+mtk_term2));
Cuda_FixNHCuda_nh_v_press_and_nve_v_NoBias(&cuda->shared_data, groupbit, factor,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal,(pstyle == TRICLINIC)?1:0);
}
else
Cuda_FixNHCuda_nve_v(&cuda->shared_data,groupbit,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal);
}
else if(which==BIAS)
{
if(pstat_flag)
{
compute_press_target();
nh_omega_dot();
factor[0] = exp(-dt4*(omega_dot[0]+mtk_term2));
factor[1] = exp(-dt4*(omega_dot[1]+mtk_term2));
factor[2] = exp(-dt4*(omega_dot[2]+mtk_term2));
if(!temperature->cudable)
{
nh_v_press();
cuda->cu_v->upload();
}
else
{
int groupbit_org=temperature->groupbit;
temperature->groupbit=groupbit;
temperature->remove_bias_all();
Cuda_FixNHCuda_nh_v_press(&cuda->shared_data, groupbit, factor,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal,(pstyle == TRICLINIC)?1:0);
temperature->restore_bias_all();
temperature->groupbit=groupbit_org;
}
}
Cuda_FixNHCuda_nve_v(&cuda->shared_data,groupbit,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal);
}
// remap simulation box by 1/2 step
if (pstat_flag) remap();
Cuda_FixNHCuda_nve_x(&cuda->shared_data,groupbit,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal);
// remap simulation box by 1/2 step
// redo KSpace coeffs since volume has changed
if (pstat_flag) {
remap();
if (kspace_flag) force->kspace->setup();
}
}
/* ----------------------------------------------------------------------
2nd half of Verlet update
------------------------------------------------------------------------- */
void FixNHCuda::final_integrate()
{
if(!temperature->cudable) cuda->downloadAll();
if(which==NOBIAS)
{
if(pstat_flag)
{
factor[0] = exp(-dt4*(omega_dot[0]+mtk_term2));
factor[1] = exp(-dt4*(omega_dot[1]+mtk_term2));
factor[2] = exp(-dt4*(omega_dot[2]+mtk_term2));
Cuda_FixNHCuda_nve_v_and_nh_v_press_NoBias(&cuda->shared_data, groupbit, factor,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal,(pstyle == TRICLINIC)?1:0);
}
else
Cuda_FixNHCuda_nve_v(&cuda->shared_data,groupbit,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal);
}
else if(which==BIAS)
{
Cuda_FixNHCuda_nve_v(&cuda->shared_data,groupbit,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal);
if(pstat_flag)
{
factor[0] = exp(-dt4*(omega_dot[0]+mtk_term2));
factor[1] = exp(-dt4*(omega_dot[1]+mtk_term2));
factor[2] = exp(-dt4*(omega_dot[2]+mtk_term2));
if(!temperature->cudable)
{
cuda->cu_v->download();
nh_v_press();
cuda->cu_v->upload();
}
else
{
int groupbit_org=temperature->groupbit;
temperature->groupbit=groupbit;
temperature->remove_bias_all();
Cuda_FixNHCuda_nh_v_press(&cuda->shared_data, groupbit, factor,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal,(pstyle == TRICLINIC)?1:0);
temperature->restore_bias_all();
temperature->groupbit=groupbit_org;
}
}
}
// compute new T,P
// compute appropriately coupled elements of mvv_current
if(!temperature->cudable) cuda->cu_v->download();
t_current = temperature->compute_scalar();
if (pstat_flag) {
if (pstyle == ISO) double tmp = pressure->compute_scalar();
else pressure->compute_vector();
couple();
pressure->addstep(update->ntimestep+1);
}
if (pstat_flag) nh_omega_dot();
// update eta_dot
// update eta_press_dot
if (tstat_flag) nhc_temp_integrate();
if (pstat_flag && mpchain) nhc_press_integrate();
}
/* ---------------------------------------------------------------------- */
void FixNHCuda::initial_integrate_respa(int vflag, int ilevel, int iloop)
{
int i;
// set timesteps by level
dtv = step_respa[ilevel];
dtf = 0.5 * step_respa[ilevel] * force->ftm2v;
dthalf = 0.5 * step_respa[ilevel];
// outermost level - update eta_dot and omega_dot, apply to v, remap box
// all other levels - NVE update of v
// x,v updates only performed for atoms in group
if (ilevel == nlevels_respa-1) {
// update eta_press_dot
if (pstat_flag && mpchain) nhc_press_integrate();
// update eta_dot
if (tstat_flag) {
double delta = update->ntimestep - update->beginstep;
delta /= update->endstep - update->beginstep;
t_target = t_start + delta * (t_stop-t_start);
eta_mass[0] = tdof * boltz * t_target / (t_freq*t_freq);
for (int ich = 1; ich < mtchain; ich++)
eta_mass[ich] = boltz * t_target / (t_freq*t_freq);
nhc_temp_integrate();
}
// recompute pressure to account for change in KE
// t_current is up-to-date, but compute_temperature is not
// compute appropriately coupled elements of mvv_current
if (pstat_flag) {
if (pstyle == ISO) {
temperature->compute_scalar();
double tmp = pressure->compute_scalar();
} else {
temperature->compute_vector();
pressure->compute_vector();
}
couple();
pressure->addstep(update->ntimestep+1);
if (mtk_flag) couple_ke();
}
if (pstat_flag) {
compute_press_target();
nh_omega_dot();
nh_v_press();
}
nve_v();
} else nve_v();
// innermost level - also update x only for atoms in group
// if barostat, perform 1/2 step remap before and after
if (ilevel == 0) {
if (pstat_flag) remap();
nve_x();
if (pstat_flag) remap();
}
// if barostat, redo KSpace coeffs at outermost level,
// since volume has changed
if (ilevel == nlevels_respa-1 && kspace_flag && pstat_flag)
force->kspace->setup();
}
/* ---------------------------------------------------------------------- */
void FixNHCuda::final_integrate_respa(int ilevel, int iloop)
{
// set timesteps by level
dtf = 0.5 * step_respa[ilevel] * force->ftm2v;
dthalf = 0.5 * step_respa[ilevel];
// outermost level - update eta_dot and omega_dot, apply via final_integrate
// all other levels - NVE update of v
if (ilevel == nlevels_respa-1) final_integrate();
else nve_v();
}
/* ---------------------------------------------------------------------- */
void FixNHCuda::couple()
{
double *tensor = pressure->vector;
if (pstyle == ISO)
p_current[0] = p_current[1] = p_current[2] = pressure->scalar;
else if (pcouple == XYZ) {
double ave = 1.0/3.0 * (tensor[0] + tensor[1] + tensor[2]);
p_current[0] = p_current[1] = p_current[2] = ave;
} else if (pcouple == XY) {
double ave = 0.5 * (tensor[0] + tensor[1]);
p_current[0] = p_current[1] = ave;
p_current[2] = tensor[2];
} else if (pcouple == YZ) {
double ave = 0.5 * (tensor[1] + tensor[2]);
p_current[1] = p_current[2] = ave;
p_current[0] = tensor[0];
} else if (pcouple == XZ) {
double ave = 0.5 * (tensor[0] + tensor[2]);
p_current[0] = p_current[2] = ave;
p_current[1] = tensor[1];
} else {
p_current[0] = tensor[0];
p_current[1] = tensor[1];
p_current[2] = tensor[2];
}
// switch order from xy-xz-yz to Voigt
if (pstyle == TRICLINIC) {
p_current[3] = tensor[5];
p_current[4] = tensor[4];
p_current[5] = tensor[3];
}
}
/* ---------------------------------------------------------------------- */
void FixNHCuda::couple_ke()
{
double *tensor = temperature->vector;
if (pstyle == ISO)
mvv_current[0] = mvv_current[1] = mvv_current[2] =
tdof * boltz * t_current/dimension;
else if (pcouple == XYZ) {
double ave = 1.0/3.0 * (tensor[0] + tensor[1] + tensor[2]);
mvv_current[0] = mvv_current[1] = mvv_current[2] = ave;
} else if (pcouple == XY) {
double ave = 0.5 * (tensor[0] + tensor[1]);
mvv_current[0] = mvv_current[1] = ave;
mvv_current[2] = tensor[2];
} else if (pcouple == YZ) {
double ave = 0.5 * (tensor[1] + tensor[2]);
mvv_current[1] = mvv_current[2] = ave;
mvv_current[0] = tensor[0];
} else if (pcouple == XZ) {
double ave = 0.5 * (tensor[0] + tensor[2]);
mvv_current[0] = mvv_current[2] = ave;
mvv_current[1] = tensor[1];
} else {
mvv_current[0] = tensor[0];
mvv_current[1] = tensor[1];
mvv_current[2] = tensor[2];
}
}
/* ----------------------------------------------------------------------
change box size
remap all atoms or fix group atoms depending on allremap flag
if rigid bodies exist, scale rigid body centers-of-mass
------------------------------------------------------------------------- */
void FixNHCuda::remap()
{
int i;
double oldlo,oldhi,ctr;
double **x = atom->x;
int *mask = atom->mask;
int nlocal = atom->nlocal;
double *h = domain->h;
// omega is not used, except for book-keeping
for (int i = 0; i < 6; i++) omega[i] += dto*omega_dot[i];
// convert pertinent atoms and rigid bodies to lamda coords
if (allremap) domain->x2lamda(nlocal);
else {
for (i = 0; i < nlocal; i++)
if (mask[i] & groupbit)
domain->x2lamda(x[i],x[i]);
}
if (nrigid)
for (i = 0; i < nrigid; i++)
modify->fix[rfix[i]]->deform(0);
// reset global and local box to new size/shape
// This operation corresponds to applying the
// translate and scale operations
// corresponding to the solution of the following ODE:
//
// h_dot = omega_dot * h
//
// where h_dot, omega_dot and h are all upper-triangular
// 3x3 tensors. In Voigt notation, the elements of the
// RHS product tensor are:
// h_dot = [0*0, 1*1, 2*2, 1*3+3*2, 0*4+5*3+4*2, 0*5+5*1]
//
// Ordering of operations preserves time symmetry.
double dto2 = dto/2.0;
double dto4 = dto/4.0;
double dto8 = dto/8.0;
if (pstyle == TRICLINIC) {
h[4] *= exp(dto8*omega_dot[0]);
h[4] += dto4*(omega_dot[5]*h[3]+omega_dot[4]*h[2]);
h[4] *= exp(dto8*omega_dot[0]);
h[3] *= exp(dto4*omega_dot[1]);
h[3] += dto2*(omega_dot[3]*h[2]);
h[3] *= exp(dto4*omega_dot[1]);
h[5] *= exp(dto4*omega_dot[0]);
h[5] += dto2*(omega_dot[5]*h[1]);
h[5] *= exp(dto4*omega_dot[0]);
h[4] *= exp(dto8*omega_dot[0]);
h[4] += dto4*(omega_dot[5]*h[3]+omega_dot[4]*h[2]);
h[4] *= exp(dto8*omega_dot[0]);
}
for (i = 0; i < 3; i++) {
if (p_flag[i]) {
oldlo = domain->boxlo[i];
oldhi = domain->boxhi[i];
ctr = 0.5 * (oldlo + oldhi);
domain->boxlo[i] = (oldlo-ctr)*exp(dto*omega_dot[i]) + ctr;
domain->boxhi[i] = (oldhi-ctr)*exp(dto*omega_dot[i]) + ctr;
}
}
if (pstyle == TRICLINIC) {
h[4] *= exp(dto8*omega_dot[0]);
h[4] += dto4*(omega_dot[5]*h[3]+omega_dot[4]*h[2]);
h[4] *= exp(dto8*omega_dot[0]);
h[3] *= exp(dto4*omega_dot[1]);
h[3] += dto2*(omega_dot[3]*h[2]);
h[3] *= exp(dto4*omega_dot[1]);
h[5] *= exp(dto4*omega_dot[0]);
h[5] += dto2*(omega_dot[5]*h[1]);
h[5] *= exp(dto4*omega_dot[0]);
h[4] *= exp(dto8*omega_dot[0]);
h[4] += dto4*(omega_dot[5]*h[3]+omega_dot[4]*h[2]);
h[4] *= exp(dto8*omega_dot[0]);
domain->yz = h[3];
domain->xz = h[4];
domain->xy = h[5];
if (domain->yz < -0.5*domain->yprd || domain->yz > 0.5*domain->yprd ||
domain->xz < -0.5*domain->xprd || domain->xz > 0.5*domain->xprd ||
domain->xy < -0.5*domain->xprd || domain->xy > 0.5*domain->xprd)
error->all("Fix npt/nph has tilted box too far - "
"box flips are not yet implemented");
}
domain->set_global_box();
domain->set_local_box();
// convert pertinent atoms and rigid bodies back to box coords
if (allremap) domain->lamda2x(nlocal);
else {
for (i = 0; i < nlocal; i++)
if (mask[i] & groupbit)
domain->lamda2x(x[i],x[i]);
}
if (nrigid)
for (i = 0; i < nrigid; i++)
modify->fix[rfix[i]]->deform(1);
}
/* ----------------------------------------------------------------------
pack entire state of Fix into one write
------------------------------------------------------------------------- */
void FixNHCuda::write_restart(FILE *fp)
{
int nsize = 2;
if (tstat_flag) nsize += 1 + 2*mtchain;
if (pstat_flag) {
nsize += 16 + 2*mpchain;
if (deviatoric_flag) nsize += 6;
}
double* list = (double *) memory->smalloc(nsize*sizeof(double),"nh:list");
int n = 0;
list[n++] = tstat_flag;
if (tstat_flag) {
list[n++] = mtchain;
for (int ich = 0; ich < mtchain; ich++)
list[n++] = eta[ich];
for (int ich = 0; ich < mtchain; ich++)
list[n++] = eta_dot[ich];
}
list[n++] = pstat_flag;
if (pstat_flag) {
list[n++] = omega[0];
list[n++] = omega[1];
list[n++] = omega[2];
list[n++] = omega[3];
list[n++] = omega[4];
list[n++] = omega[5];
list[n++] = omega_dot[0];
list[n++] = omega_dot[1];
list[n++] = omega_dot[2];
list[n++] = omega_dot[3];
list[n++] = omega_dot[4];
list[n++] = omega_dot[5];
list[n++] = vol0;
list[n++] = t0;
list[n++] = mpchain;
if (mpchain) {
for (int ich = 0; ich < mpchain; ich++)
list[n++] = etap[ich];
for (int ich = 0; ich < mpchain; ich++)
list[n++] = etap_dot[ich];
}
list[n++] = deviatoric_flag;
if (deviatoric_flag) {
list[n++] = h0_inv[0];
list[n++] = h0_inv[1];
list[n++] = h0_inv[2];
list[n++] = h0_inv[3];
list[n++] = h0_inv[4];
list[n++] = h0_inv[5];
}
}
if (comm->me == 0) {
int size = nsize * sizeof(double);
fwrite(&size,sizeof(int),1,fp);
fwrite(list,sizeof(double),nsize,fp);
}
memory->sfree(list);
}
/* ----------------------------------------------------------------------
use state info from restart file to restart the Fix
------------------------------------------------------------------------- */
void FixNHCuda::restart(char *buf)
{
int n = 0;
double *list = (double *) buf;
int flag = static_cast<int> (list[n++]);
if (flag) {
int m = static_cast<int> (list[n++]);
if (tstat_flag && m == mtchain) {
for (int ich = 0; ich < mtchain; ich++)
eta[ich] = list[n++];
for (int ich = 0; ich < mtchain; ich++)
eta_dot[ich] = list[n++];
} else n += 2*m;
}
flag = static_cast<int> (list[n++]);
if (flag) {
omega[0] = list[n++];
omega[1] = list[n++];
omega[2] = list[n++];
omega[3] = list[n++];
omega[4] = list[n++];
omega[5] = list[n++];
omega_dot[0] = list[n++];
omega_dot[1] = list[n++];
omega_dot[2] = list[n++];
omega_dot[3] = list[n++];
omega_dot[4] = list[n++];
omega_dot[5] = list[n++];
vol0 = list[n++];
t0 = list[n++];
int m = static_cast<int> (list[n++]);
if (pstat_flag && m == mpchain) {
for (int ich = 0; ich < mpchain; ich++)
etap[ich] = list[n++];
for (int ich = 0; ich < mpchain; ich++)
etap_dot[ich] = list[n++];
} else n+=2*m;
flag = static_cast<int> (list[n++]);
if (flag) {
h0_inv[0] = list[n++];
h0_inv[1] = list[n++];
h0_inv[2] = list[n++];
h0_inv[3] = list[n++];
h0_inv[4] = list[n++];
h0_inv[5] = list[n++];
}
}
}
/* ---------------------------------------------------------------------- */
int FixNHCuda::modify_param(int narg, char **arg)
{
if (strcmp(arg[0],"temp") == 0) {
if (narg < 2) error->all("Illegal fix_modify command");
if (tflag) {
modify->delete_compute(id_temp);
tflag = 0;
}
delete [] id_temp;
int n = strlen(arg[1]) + 1;
id_temp = new char[n];
strcpy(id_temp,arg[1]);
int icompute = modify->find_compute(arg[1]);
if (icompute < 0) error->all("Could not find fix_modify temperature ID");
temperature = modify->compute[icompute];
if (temperature->tempflag == 0)
error->all("Fix_modify temperature ID does not compute temperature");
if (temperature->igroup != 0 && comm->me == 0)
error->warning("Temperature for fix modify is not for group all");
// reset id_temp of pressure to new temperature ID
if (pstat_flag) {
icompute = modify->find_compute(id_press);
if (icompute < 0)
error->all("Pressure ID for fix modify does not exist");
modify->compute[icompute]->reset_extra_compute_fix(id_temp);
}
return 2;
} else if (strcmp(arg[0],"press") == 0) {
if (narg < 2) error->all("Illegal fix_modify command");
if (!pstat_flag) error->all("Illegal fix_modify command");
if (pflag) {
modify->delete_compute(id_press);
pflag = 0;
}
delete [] id_press;
int n = strlen(arg[1]) + 1;
id_press = new char[n];
strcpy(id_press,arg[1]);
int icompute = modify->find_compute(arg[1]);
if (icompute < 0) error->all("Could not find fix_modify pressure ID");
pressure = modify->compute[icompute];
if (pressure->pressflag == 0)
error->all("Fix_modify pressure ID does not compute pressure");
return 2;
}
return 0;
}
/* ---------------------------------------------------------------------- */
double FixNHCuda::compute_scalar()
{
int i;
double volume;
double energy;
double kt = boltz * t_target;
double lkt = tdof * kt;
double lkt_press = kt;
int ich;
if (dimension == 3) volume = domain->xprd * domain->yprd * domain->zprd;
else volume = domain->xprd * domain->yprd;
energy = 0.0;
// thermostat chain energy is equivalent to Eq. (2) in
// Martyna, Tuckerman, Tobias, Klein, Mol Phys, 87, 1117
// Sum(0.5*p_eta_k^2/Q_k,k=1,M) + L*k*T*eta_1 + Sum(k*T*eta_k,k=2,M),
// where L = tdof
// M = mtchain
// p_eta_k = Q_k*eta_dot[k-1]
// Q_1 = L*k*T/t_freq^2
// Q_k = k*T/t_freq^2, k > 1
if (tstat_flag) {
energy += lkt * eta[0] + 0.5*eta_mass[0]*eta_dot[0]*eta_dot[0];
for (ich = 1; ich < mtchain; ich++)
energy += kt * eta[ich] + 0.5*eta_mass[ich]*eta_dot[ich]*eta_dot[ich];
}
// barostat energy is equivalent to Eq. (8) in
// Martyna, Tuckerman, Tobias, Klein, Mol Phys, 87, 1117
// Sum(0.5*p_omega^2/W + P*V),
// where N = natoms
// p_omega = W*omega_dot
// W = N*k*T/p_freq^2
// sum is over barostatted dimensions
if (pstat_flag) {
for (i = 0; i < 3; i++)
if (p_flag[i])
energy += 0.5*omega_dot[i]*omega_dot[i]*omega_mass[i] +
p_hydro*(volume-vol0) / (pdim*nktv2p);
if (pstyle == TRICLINIC) {
for (i = 3; i < 6; i++)
if (p_flag[i])
energy += 0.5*omega_dot[i]*omega_dot[i]*omega_mass[i];
}
// extra contributions from thermostat chain for barostat
if (mpchain) {
energy += lkt_press * etap[0] + 0.5*etap_mass[0]*etap_dot[0]*etap_dot[0];
for (ich = 1; ich < mpchain; ich++)
energy += kt * etap[ich] +
0.5*etap_mass[ich]*etap_dot[ich]*etap_dot[ich];
}
// extra contribution from strain energy
if (deviatoric_flag) energy += compute_strain_energy();
}
return energy;
}
/* ----------------------------------------------------------------------
return a single element of the following vectors, in this order:
eta[tchain], eta_dot[tchain], omega[ndof], omega_dot[ndof]
etap[pchain], etap_dot[pchain], PE_eta[tchain], KE_eta_dot[tchain]
PE_omega[ndof], KE_omega_dot[ndof], PE_etap[pchain], KE_etap_dot[pchain]
PE_strain[1]
if no thermostat exists, related quantities are omitted from the list
if no barostat exists, related quantities are omitted from the list
ndof = 1,3,6 degrees of freedom for pstyle = ISO,ANISO,TRI
------------------------------------------------------------------------- */
double FixNHCuda::compute_vector(int n)
{
int ilen;
if (tstat_flag) {
ilen = mtchain;
if (n < ilen) return eta[n];
n -= ilen;
ilen = mtchain;
if (n < ilen) return eta_dot[n];
n -= ilen;
}
if (pstat_flag) {
if (pstyle == ISO) {
ilen = 1;
if (n < ilen) return omega[n];
n -= ilen;
} else if (pstyle == ANISO) {
ilen = 3;
if (n < ilen) return omega[n];
n -= ilen;
} else {
ilen = 6;
if (n < ilen) return omega[n];
n -= ilen;
}
if (pstyle == ISO) {
ilen = 1;
if (n < ilen) return omega_dot[n];
n -= ilen;
} else if (pstyle == ANISO) {
ilen = 3;
if (n < ilen) return omega_dot[n];
n -= ilen;
} else {
ilen = 6;
if (n < ilen) return omega_dot[n];
n -= ilen;
}
if (mpchain) {
ilen = mpchain;
if (n < ilen) return etap[n];
n -= ilen;
ilen = mpchain;
if (n < ilen) return etap_dot[n];
n -= ilen;
}
}
int i;
double volume;
double kt = boltz * t_target;
double lkt = tdof * kt;
double lkt_press = kt;
int ich;
if (dimension == 3) volume = domain->xprd * domain->yprd * domain->zprd;
else volume = domain->xprd * domain->yprd;
if (tstat_flag) {
ilen = mtchain;
if (n < ilen) {
ich = n;
if (ich == 0)
return lkt * eta[0];
else
return kt * eta[ich];
}
n -= ilen;
ilen = mtchain;
if (n < ilen) {
ich = n;
if (ich == 0)
return 0.5*eta_mass[0]*eta_dot[0]*eta_dot[0];
else
return 0.5*eta_mass[ich]*eta_dot[ich]*eta_dot[ich];
}
n -= ilen;
}
if (pstat_flag) {
if (pstyle == ISO) {
ilen = 1;
if (n < ilen)
return p_hydro*(volume-vol0) / nktv2p;
n -= ilen;
} else if (pstyle == ANISO) {
ilen = 3;
if (n < ilen)
if (p_flag[n])
return p_hydro*(volume-vol0) / (pdim*nktv2p);
else
return 0.0;
n -= ilen;
} else {
ilen = 6;
if (n < ilen)
if (n > 2) return 0.0;
else if (p_flag[n])
return p_hydro*(volume-vol0) / (pdim*nktv2p);
else
return 0.0;
n -= ilen;
}
if (pstyle == ISO) {
ilen = 1;
if (n < ilen)
return pdim*0.5*omega_dot[n]*omega_dot[n]*omega_mass[n];
n -= ilen;
} else if (pstyle == ANISO) {
ilen = 3;
if (n < ilen)
if (p_flag[n])
return 0.5*omega_dot[n]*omega_dot[n]*omega_mass[n];
else return 0.0;
n -= ilen;
} else {
ilen = 6;
if (n < ilen)
if (p_flag[n])
return 0.5*omega_dot[n]*omega_dot[n]*omega_mass[n];
else return 0.0;
n -= ilen;
}
if (mpchain) {
ilen = mpchain;
if (n < ilen) {
ich = n;
if (ich == 0) return lkt_press * etap[0];
else return kt * etap[ich];
}
n -= ilen;
ilen = mpchain;
if (n < ilen) {
ich = n;
if (ich == 0)
return 0.5*etap_mass[0]*etap_dot[0]*etap_dot[0];
else
return 0.5*etap_mass[ich]*etap_dot[ich]*etap_dot[ich];
}
n -= ilen;
}
if (deviatoric_flag) {
ilen = 1;
if (n < ilen)
return compute_strain_energy();
n -= ilen;
}
}
return 0.0;
}
/* ---------------------------------------------------------------------- */
void FixNHCuda::reset_dt()
{
dtv = update->dt;
dtf = 0.5 * update->dt * force->ftm2v;
dthalf = 0.5 * update->dt;
dt4 = 0.25 * update->dt;
dt8 = 0.125 * update->dt;
dto = dthalf;
// If using respa, then remap is performed in innermost level
if (strcmp(update->integrate_style,"respa") == 0)
dto = 0.5*step_respa[0];
p_freq_max = 0.0;
if (pstat_flag) {
p_freq_max = MAX(p_freq[0],p_freq[1]);
p_freq_max = MAX(p_freq_max,p_freq[2]);
if (pstyle == TRICLINIC) {
p_freq_max = MAX(p_freq_max,p_freq[3]);
p_freq_max = MAX(p_freq_max,p_freq[4]);
p_freq_max = MAX(p_freq_max,p_freq[5]);
}
pdrag_factor = 1.0 - (update->dt * p_freq_max * drag / nc_pchain);
}
if (tstat_flag)
tdrag_factor = 1.0 - (update->dt * t_freq * drag / nc_tchain);
}
/* ----------------------------------------------------------------------
perform half-step update of chain thermostat variables
------------------------------------------------------------------------- */
void FixNHCuda::nhc_temp_integrate()
{
int ich;
double expfac;
double lkt = tdof * boltz * t_target;
double kecurrent = tdof * boltz * t_current;
eta_dotdot[0] = (kecurrent - lkt)/eta_mass[0];
double ncfac = 1.0/nc_tchain;
for (int iloop = 0; iloop < nc_tchain; iloop++) {
for (ich = mtchain-1; ich > 0; ich--) {
expfac = exp(-ncfac*dt8*eta_dot[ich+1]);
eta_dot[ich] *= expfac;
eta_dot[ich] += eta_dotdot[ich] * ncfac*dt4;
eta_dot[ich] *= tdrag_factor;
eta_dot[ich] *= expfac;
}
expfac = exp(-ncfac*dt8*eta_dot[1]);
eta_dot[0] *= expfac;
eta_dot[0] += eta_dotdot[0] * ncfac*dt4;
eta_dot[0] *= tdrag_factor;
eta_dot[0] *= expfac;
factor_eta = exp(-ncfac*dthalf*eta_dot[0]);
if(which==NOBIAS)
Cuda_FixNHCuda_nh_v_temp(&cuda->shared_data,groupbit,factor_eta,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal);
else if(which==BIAS)
{
if(!temperature->cudable)
{
cuda->downloadAll();
nh_v_temp();
cuda->cu_v->upload();
}
else
{
int groupbit_org=temperature->groupbit;
temperature->groupbit=groupbit;
temperature->remove_bias_all();
Cuda_FixNHCuda_nh_v_temp(&cuda->shared_data,groupbit,factor_eta,(igroup == atom->firstgroup)?atom->nfirst:atom->nlocal);
temperature->restore_bias_all();
temperature->groupbit=groupbit_org;
}
}
// rescale temperature due to velocity scaling
// should not be necessary to explicitly recompute the temperature
t_current *= factor_eta*factor_eta;
kecurrent = tdof * boltz * t_current;
eta_dotdot[0] = (kecurrent - lkt)/eta_mass[0];
for (ich = 0; ich < mtchain; ich++)
eta[ich] += ncfac*dthalf*eta_dot[ich];
eta_dot[0] *= expfac;
eta_dot[0] += eta_dotdot[0] * ncfac*dt4;
eta_dot[0] *= expfac;
for (ich = 1; ich < mtchain; ich++) {
expfac = exp(-ncfac*dt8*eta_dot[ich+1]);
eta_dot[ich] *= expfac;
eta_dotdot[ich] = (eta_mass[ich-1]*eta_dot[ich-1]*eta_dot[ich-1]
- boltz * t_target)/eta_mass[ich];
eta_dot[ich] += eta_dotdot[ich] * ncfac*dt4;
eta_dot[ich] *= expfac;
}
}
}
/* ----------------------------------------------------------------------
perform half-step update of chain thermostat variables for barostat
scale barostat velocities
------------------------------------------------------------------------- */
void FixNHCuda::nhc_press_integrate()
{
int ich,i;
double expfac,factor_etap,wmass,kecurrent;
double kt = boltz * t_target;
double lkt_press = kt;
kecurrent = 0.0;
for (i = 0; i < 3; i++)
if (p_flag[i]) kecurrent += omega_mass[i]*omega_dot[i]*omega_dot[i];
if (pstyle == TRICLINIC) {
for (i = 3; i < 6; i++)
if (p_flag[i]) kecurrent += omega_mass[i]*omega_dot[i]*omega_dot[i];
}
etap_dotdot[0] = (kecurrent - lkt_press)/etap_mass[0];
double ncfac = 1.0/nc_pchain;
for (int iloop = 0; iloop < nc_pchain; iloop++) {
for (ich = mpchain-1; ich > 0; ich--) {
expfac = exp(-ncfac*dt8*etap_dot[ich+1]);
etap_dot[ich] *= expfac;
etap_dot[ich] += etap_dotdot[ich] * ncfac*dt4;
etap_dot[ich] *= pdrag_factor;
etap_dot[ich] *= expfac;
}
expfac = exp(-ncfac*dt8*etap_dot[1]);
etap_dot[0] *= expfac;
etap_dot[0] += etap_dotdot[0] * ncfac*dt4;
etap_dot[0] *= pdrag_factor;
etap_dot[0] *= expfac;
for (ich = 0; ich < mpchain; ich++)
etap[ich] += ncfac*dthalf*etap_dot[ich];
factor_etap = exp(-ncfac*dthalf*etap_dot[0]);
for (i = 0; i < 3; i++)
if (p_flag[i]) omega_dot[i] *= factor_etap;
if (pstyle == TRICLINIC) {
for (i = 3; i < 6; i++)
if (p_flag[i]) omega_dot[i] *= factor_etap;
}
kecurrent = 0.0;
for (i = 0; i < 3; i++)
if (p_flag[i]) kecurrent += omega_mass[i]*omega_dot[i]*omega_dot[i];
if (pstyle == TRICLINIC) {
for (i = 3; i < 6; i++)
if (p_flag[i]) kecurrent += omega_mass[i]*omega_dot[i]*omega_dot[i];
}
etap_dotdot[0] = (kecurrent - lkt_press)/etap_mass[0];
etap_dot[0] *= expfac;
etap_dot[0] += etap_dotdot[0] * ncfac*dt4;
etap_dot[0] *= expfac;
for (ich = 1; ich < mpchain; ich++) {
expfac = exp(-ncfac*dt8*etap_dot[ich+1]);
etap_dot[ich] *= expfac;
etap_dotdot[ich] =
(etap_mass[ich-1]*etap_dot[ich-1]*etap_dot[ich-1] - boltz*t_target) /
etap_mass[ich];
etap_dot[ich] += etap_dotdot[ich] * ncfac*dt4;
etap_dot[ich] *= expfac;
}
}
}
/* ----------------------------------------------------------------------
perform half-step barostat scaling of velocities
-----------------------------------------------------------------------*/
void FixNHCuda::nh_v_press()
{
double factor[3];
double **v = atom->v;
int *mask = atom->mask;
int nlocal = atom->nlocal;
if (igroup == atom->firstgroup) nlocal = atom->nfirst;
factor[0] = exp(-dt4*(omega_dot[0]+mtk_term2));
factor[1] = exp(-dt4*(omega_dot[1]+mtk_term2));
factor[2] = exp(-dt4*(omega_dot[2]+mtk_term2));
if (which == NOBIAS) {
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
v[i][0] *= factor[0];
v[i][1] *= factor[1];
v[i][2] *= factor[2];
if (pstyle == TRICLINIC) {
v[i][0] += -dthalf*(v[i][1]*omega_dot[5] + v[i][2]*omega_dot[4]);
v[i][1] += -dthalf*v[i][2]*omega_dot[3];
}
v[i][0] *= factor[0];
v[i][1] *= factor[1];
v[i][2] *= factor[2];
}
}
} else if (which == BIAS) {
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
temperature->remove_bias(i,v[i]);
v[i][0] *= factor[0];
v[i][1] *= factor[1];
v[i][2] *= factor[2];
if (pstyle == TRICLINIC) {
v[i][0] += -dthalf*(v[i][1]*omega_dot[5] + v[i][2]*omega_dot[4]);
v[i][1] += -dthalf*v[i][2]*omega_dot[3];
}
v[i][0] *= factor[0];
v[i][1] *= factor[1];
v[i][2] *= factor[2];
temperature->restore_bias(i,v[i]);
}
}
}
}
/* ----------------------------------------------------------------------
perform half-step update of velocities
-----------------------------------------------------------------------*/
void FixNHCuda::nve_v()
{
double dtfm;
double **v = atom->v;
double **f = atom->f;
double *rmass = atom->rmass;
double *mass = atom->mass;
int *type = atom->type;
int *mask = atom->mask;
int nlocal = atom->nlocal;
if (igroup == atom->firstgroup) nlocal = atom->nfirst;
if (rmass) {
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
dtfm = dtf / rmass[i];
v[i][0] += dtfm*f[i][0];
v[i][1] += dtfm*f[i][1];
v[i][2] += dtfm*f[i][2];
}
}
} else {
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
dtfm = dtf / mass[type[i]];
v[i][0] += dtfm*f[i][0];
v[i][1] += dtfm*f[i][1];
v[i][2] += dtfm*f[i][2];
}
}
}
}
/* ----------------------------------------------------------------------
perform full-step update of positions
-----------------------------------------------------------------------*/
void FixNHCuda::nve_x()
{
double **x = atom->x;
double **v = atom->v;
int *mask = atom->mask;
int nlocal = atom->nlocal;
if (igroup == atom->firstgroup) nlocal = atom->nfirst;
// x update by full step only for atoms in group
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
x[i][0] += dtv * v[i][0];
x[i][1] += dtv * v[i][1];
x[i][2] += dtv * v[i][2];
}
}
}
/* ----------------------------------------------------------------------
perform half-step thermostat scaling of velocities
-----------------------------------------------------------------------*/
void FixNHCuda::nh_v_temp()
{
double **v = atom->v;
int *mask = atom->mask;
int nlocal = atom->nlocal;
if (igroup == atom->firstgroup) nlocal = atom->nfirst;
if (which == NOBIAS) {
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
v[i][0] *= factor_eta;
v[i][1] *= factor_eta;
v[i][2] *= factor_eta;
}
}
} else if (which == BIAS) {
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
temperature->remove_bias(i,v[i]);
v[i][0] *= factor_eta;
v[i][1] *= factor_eta;
v[i][2] *= factor_eta;
temperature->restore_bias(i,v[i]);
}
}
}
}
/* ----------------------------------------------------------------------
compute sigma tensor
needed whenever p_target or h0_inv changes
-----------------------------------------------------------------------*/
void FixNHCuda::compute_sigma()
{
// if nreset_h0 > 0, reset vol0 and h0_inv
// every nreset_h0 timesteps
if (nreset_h0 > 0) {
int delta = update->ntimestep - update->beginstep;
if (delta % nreset_h0 == 0) {
if (dimension == 3) vol0 = domain->xprd * domain->yprd * domain->zprd;
else vol0 = domain->xprd * domain->yprd;
h0_inv[0] = domain->h_inv[0];
h0_inv[1] = domain->h_inv[1];
h0_inv[2] = domain->h_inv[2];
h0_inv[3] = domain->h_inv[3];
h0_inv[4] = domain->h_inv[4];
h0_inv[5] = domain->h_inv[5];
}
}
// generate upper-triangular half of
// sigma = vol0*h0inv*(p_target-p_hydro)*h0inv^t
// units of sigma are are PV/L^2 e.g. atm.A
//
// [ 0 5 4 ] [ 0 5 4 ] [ 0 5 4 ] [ 0 - - ]
// [ 5 1 3 ] = [ - 1 3 ] [ 5 1 3 ] [ 5 1 - ]
// [ 4 3 2 ] [ - - 2 ] [ 4 3 2 ] [ 4 3 2 ]
sigma[0] =
vol0*(h0_inv[0]*((p_target[0]-p_hydro)*h0_inv[0] +
p_target[5]*h0_inv[5]+p_target[4]*h0_inv[4]) +
h0_inv[5]*(p_target[5]*h0_inv[0] +
(p_target[1]-p_hydro)*h0_inv[5]+p_target[3]*h0_inv[4]) +
h0_inv[4]*(p_target[4]*h0_inv[0]+p_target[3]*h0_inv[5] +
(p_target[2]-p_hydro)*h0_inv[4]));
sigma[1] =
vol0*(h0_inv[1]*((p_target[1]-p_hydro)*h0_inv[1] +
p_target[3]*h0_inv[3]) +
h0_inv[3]*(p_target[3]*h0_inv[1] +
(p_target[2]-p_hydro)*h0_inv[3]));
sigma[2] =
vol0*(h0_inv[2]*((p_target[2]-p_hydro)*h0_inv[2]));
sigma[3] =
vol0*(h0_inv[1]*(p_target[3]*h0_inv[2]) +
h0_inv[3]*((p_target[2]-p_hydro)*h0_inv[2]));
sigma[4] =
vol0*(h0_inv[0]*(p_target[4]*h0_inv[2]) +
h0_inv[5]*(p_target[3]*h0_inv[2]) +
h0_inv[4]*((p_target[2]-p_hydro)*h0_inv[2]));
sigma[5] =
vol0*(h0_inv[0]*(p_target[5]*h0_inv[1]+p_target[4]*h0_inv[3]) +
h0_inv[5]*((p_target[1]-p_hydro)*h0_inv[1]+p_target[3]*h0_inv[3]) +
h0_inv[4]*(p_target[3]*h0_inv[1]+(p_target[2]-p_hydro)*h0_inv[3]));
}
/* ----------------------------------------------------------------------
compute strain energy
-----------------------------------------------------------------------*/
double FixNHCuda::compute_strain_energy()
{
// compute strain energy = 0.5*Tr(sigma*h*h^t) in energy units
double* h = domain->h;
double d0,d1,d2;
d0 =
sigma[0]*(h[0]*h[0]+h[5]*h[5]+h[4]*h[4]) +
sigma[5]*( h[1]*h[5]+h[3]*h[4]) +
sigma[4]*( h[2]*h[4]);
d1 =
sigma[5]*( h[5]*h[1]+h[4]*h[3]) +
sigma[1]*( h[1]*h[1]+h[3]*h[3]) +
sigma[3]*( h[2]*h[3]);
d2 =
sigma[4]*( h[4]*h[2]) +
sigma[3]*( h[3]*h[2]) +
sigma[2]*( h[2]*h[2]);
double energy = 0.5*(d0+d1+d2)/nktv2p;
return energy;
}
/* ----------------------------------------------------------------------
compute deviatoric barostat force = h*sigma*h^t
-----------------------------------------------------------------------*/
void FixNHCuda::compute_deviatoric()
{
// generate upper-triangular part of h*sigma*h^t
// units of fdev are are PV, e.g. atm*A^3
// [ 0 5 4 ] [ 0 5 4 ] [ 0 5 4 ] [ 0 - - ]
// [ 5 1 3 ] = [ - 1 3 ] [ 5 1 3 ] [ 5 1 - ]
// [ 4 3 2 ] [ - - 2 ] [ 4 3 2 ] [ 4 3 2 ]
double* h = domain->h;
fdev[0] =
h[0]*(sigma[0]*h[0]+sigma[5]*h[5]+sigma[4]*h[4]) +
h[5]*(sigma[5]*h[0]+sigma[1]*h[5]+sigma[3]*h[4]) +
h[4]*(sigma[4]*h[0]+sigma[3]*h[5]+sigma[2]*h[4]);
fdev[1] =
h[1]*( sigma[1]*h[1]+sigma[3]*h[3]) +
h[3]*( sigma[3]*h[1]+sigma[2]*h[3]);
fdev[2] =
h[2]*( sigma[2]*h[2]);
fdev[3] =
h[1]*( sigma[3]*h[2]) +
h[3]*( sigma[2]*h[2]);
fdev[4] =
h[0]*( sigma[4]*h[2]) +
h[5]*( sigma[3]*h[2]) +
h[4]*( sigma[2]*h[2]);
fdev[5] =
h[0]*( sigma[5]*h[1]+sigma[4]*h[3]) +
h[5]*( sigma[1]*h[1]+sigma[3]*h[3]) +
h[4]*( sigma[3]*h[1]+sigma[2]*h[3]);
}
/* ----------------------------------------------------------------------
compute hydrostatic target pressure
-----------------------------------------------------------------------*/
void FixNHCuda::compute_press_target()
{
double delta = update->ntimestep - update->beginstep;
if (update->endstep > update->beginstep)
delta /= update->endstep - update->beginstep;
else delta = 0.0;
p_hydro = 0.0;
for (int i = 0; i < 3; i++)
if (p_flag[i]) {
p_target[i] = p_start[i] + delta * (p_stop[i]-p_start[i]);
p_hydro += p_target[i];
}
p_hydro /= pdim;
if (pstyle == TRICLINIC)
for (int i = 3; i < 6; i++)
p_target[i] = p_start[i] + delta * (p_stop[i]-p_start[i]);
// if deviatoric, recompute sigma each time p_target changes
if (deviatoric_flag) compute_sigma();
}
/* ----------------------------------------------------------------------
update omega_dot, omega, dilation
-----------------------------------------------------------------------*/
void FixNHCuda::nh_omega_dot()
{
double f_omega,volume;
if (dimension == 3) volume = domain->xprd*domain->yprd*domain->zprd;
else volume = domain->xprd*domain->yprd;
if (deviatoric_flag) compute_deviatoric();
mtk_term1 = 0.0;
if (mtk_flag)
if (pstyle == ISO) {
mtk_term1 = tdof * boltz * t_current;
mtk_term1 /= pdim * atom->natoms;
} else {
double *mvv_current = temperature->vector;
for (int i = 0; i < 3; i++)
if (p_flag[i])
mtk_term1 += mvv_current[i];
mtk_term1 /= pdim * atom->natoms;
}
for (int i = 0; i < 3; i++)
if (p_flag[i]) {
f_omega = (p_current[i]-p_hydro)*volume /
(omega_mass[i] * nktv2p) + mtk_term1 / omega_mass[i];
if (deviatoric_flag) f_omega -= fdev[i]/(omega_mass[i] * nktv2p);
omega_dot[i] += f_omega*dthalf;
omega_dot[i] *= pdrag_factor;
}
mtk_term2 = 0.0;
if (mtk_flag) {
for (int i = 0; i < 3; i++)
if (p_flag[i])
mtk_term2 += omega_dot[i];
mtk_term2 /= pdim * atom->natoms;
}
if (pstyle == TRICLINIC) {
for (int i = 3; i < 6; i++) {
if (p_flag[i]) {
f_omega = p_current[i]*volume/(omega_mass[i] * nktv2p);
if (deviatoric_flag)
f_omega -= fdev[i]/(omega_mass[i] * nktv2p);
omega_dot[i] += f_omega*dthalf;
omega_dot[i] *= pdrag_factor;
}
}
}
}

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