Changes to coulomb tables.

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@8974 f3b2605a-c512-4ea7-a41b-209d697bcdaa
This commit is contained in:
pscrozi 2012-10-17 23:28:42 +00:00
parent 0b10887ad4
commit 7b8bede0f1
2 changed files with 240 additions and 49 deletions

View File

@ -29,6 +29,7 @@
#include "domain.h" #include "domain.h"
#include "comm.h" #include "comm.h"
#include "force.h" #include "force.h"
#include "kspace.h"
#include "update.h" #include "update.h"
#include "accelerator_cuda.h" #include "accelerator_cuda.h"
#include "suffix.h" #include "suffix.h"
@ -38,6 +39,8 @@
using namespace LAMMPS_NS; using namespace LAMMPS_NS;
#define EWALD_F 1.12837917
enum{RLINEAR,RSQ,BMP}; enum{RLINEAR,RSQ,BMP};
/* ---------------------------------------------------------------------- */ /* ---------------------------------------------------------------------- */
@ -241,6 +244,236 @@ void Pair::init_list(int which, NeighList *ptr)
list = ptr; list = ptr;
} }
/* ----------------------------------------------------------------------
setup force tables used in compute routines
------------------------------------------------------------------------- */
void Pair::init_tables(double cut_coul, double *cut_respa)
{
int masklo,maskhi;
double r,grij,expm2,derfc,egamma,fgamma,rsw;
double qqrd2e = force->qqrd2e;
if (force->kspace == NULL)
error->all(FLERR,"Pair style requres a KSpace style");
double g_ewald = force->kspace->g_ewald;
double cut_coulsq = cut_coul * cut_coul;
tabinnersq = tabinner*tabinner;
init_bitmap(tabinner,cut_coul,ncoultablebits,
masklo,maskhi,ncoulmask,ncoulshiftbits);
int ntable = 1;
for (int i = 0; i < ncoultablebits; i++) ntable *= 2;
// linear lookup tables of length N = 2^ncoultablebits
// stored value = value at lower edge of bin
// d values = delta from lower edge to upper edge of bin
if (ftable) free_tables();
memory->create(rtable,ntable,"pair:rtable");
memory->create(ftable,ntable,"pair:ftable");
memory->create(ctable,ntable,"pair:ctable");
memory->create(etable,ntable,"pair:etable");
memory->create(drtable,ntable,"pair:drtable");
memory->create(dftable,ntable,"pair:dftable");
memory->create(dctable,ntable,"pair:dctable");
memory->create(detable,ntable,"pair:detable");
if (cut_respa == NULL) {
vtable = ptable = dvtable = dptable = NULL;
} else {
memory->create(vtable,ntable,"pair:vtable");
memory->create(ptable,ntable,"pair:ptable");
memory->create(dvtable,ntable,"pair:dvtable");
memory->create(dptable,ntable,"pair:dptable");
}
union_int_float_t rsq_lookup;
union_int_float_t minrsq_lookup;
int itablemin;
minrsq_lookup.i = 0 << ncoulshiftbits;
minrsq_lookup.i |= maskhi;
for (int i = 0; i < ntable; i++) {
rsq_lookup.i = i << ncoulshiftbits;
rsq_lookup.i |= masklo;
if (rsq_lookup.f < tabinnersq) {
rsq_lookup.i = i << ncoulshiftbits;
rsq_lookup.i |= maskhi;
}
r = sqrtf(rsq_lookup.f);
if (msmflag) {
egamma = 1.0 - (r/cut_coul)*force->kspace->gamma(r/cut_coul);
fgamma = 1.0 + (rsq_lookup.f/cut_coulsq)*force->kspace->dgamma(r/cut_coul);
} else {
grij = g_ewald * r;
expm2 = exp(-grij*grij);
derfc = erfc(grij);
}
if (cut_respa == NULL) {
rtable[i] = rsq_lookup.f;
ctable[i] = qqrd2e/r;
if (msmflag) {
ftable[i] = qqrd2e/r * fgamma;
etable[i] = qqrd2e/r * egamma;
} else {
ftable[i] = qqrd2e/r * (derfc + EWALD_F*grij*expm2);
etable[i] = qqrd2e/r * derfc;
}
} else {
rtable[i] = rsq_lookup.f;
ctable[i] = 0.0;
ptable[i] = qqrd2e/r;
if (msmflag) {
ftable[i] = qqrd2e/r * (fgamma - 1.0);
etable[i] = qqrd2e/r * egamma;
vtable[i] = qqrd2e/r * fgamma;
} else {
ftable[i] = qqrd2e/r * (derfc + EWALD_F*grij*expm2 - 1.0);
etable[i] = qqrd2e/r * derfc;
vtable[i] = qqrd2e/r * (derfc + EWALD_F*grij*expm2);
}
if (rsq_lookup.f > cut_respa[2]*cut_respa[2]) {
if (rsq_lookup.f < cut_respa[3]*cut_respa[3]) {
rsw = (r - cut_respa[2])/(cut_respa[3] - cut_respa[2]);
ftable[i] += qqrd2e/r * rsw*rsw*(3.0 - 2.0*rsw);
ctable[i] = qqrd2e/r * rsw*rsw*(3.0 - 2.0*rsw);
} else {
if (msmflag) ftable[i] = qqrd2e/r * fgamma;
else ftable[i] = qqrd2e/r * (derfc + EWALD_F*grij*expm2);
ctable[i] = qqrd2e/r;
}
}
}
minrsq_lookup.f = MIN(minrsq_lookup.f,rsq_lookup.f);
}
tabinnersq = minrsq_lookup.f;
int ntablem1 = ntable - 1;
for (int i = 0; i < ntablem1; i++) {
drtable[i] = 1.0/(rtable[i+1] - rtable[i]);
dftable[i] = ftable[i+1] - ftable[i];
dctable[i] = ctable[i+1] - ctable[i];
detable[i] = etable[i+1] - etable[i];
}
if (cut_respa) {
for (int i = 0; i < ntablem1; i++) {
dvtable[i] = vtable[i+1] - vtable[i];
dptable[i] = ptable[i+1] - ptable[i];
}
}
// get the delta values for the last table entries
// tables are connected periodically between 0 and ntablem1
drtable[ntablem1] = 1.0/(rtable[0] - rtable[ntablem1]);
dftable[ntablem1] = ftable[0] - ftable[ntablem1];
dctable[ntablem1] = ctable[0] - ctable[ntablem1];
detable[ntablem1] = etable[0] - etable[ntablem1];
if (cut_respa) {
dvtable[ntablem1] = vtable[0] - vtable[ntablem1];
dptable[ntablem1] = ptable[0] - ptable[ntablem1];
}
// get the correct delta values at itablemax
// smallest r is in bin itablemin
// largest r is in bin itablemax, which is itablemin-1,
// or ntablem1 if itablemin=0
// deltas at itablemax only needed if corresponding rsq < cut*cut
// if so, compute deltas between rsq and cut*cut
double f_tmp,c_tmp,e_tmp,p_tmp,v_tmp;
p_tmp = 0.0;
v_tmp = 0.0;
itablemin = minrsq_lookup.i & ncoulmask;
itablemin >>= ncoulshiftbits;
int itablemax = itablemin - 1;
if (itablemin == 0) itablemax = ntablem1;
rsq_lookup.i = itablemax << ncoulshiftbits;
rsq_lookup.i |= maskhi;
if (rsq_lookup.f < cut_coulsq) {
rsq_lookup.f = cut_coulsq;
r = sqrtf(rsq_lookup.f);
if (msmflag) {
egamma = 1.0 - (r/cut_coul)*force->kspace->gamma(r/cut_coul);
fgamma = 1.0 + (rsq_lookup.f/cut_coulsq)*force->kspace->dgamma(r/cut_coul);
} else {
grij = g_ewald * r;
expm2 = exp(-grij*grij);
derfc = erfc(grij);
}
if (cut_respa == NULL) {
c_tmp = qqrd2e/r;
if (msmflag) {
f_tmp = qqrd2e/r * fgamma;
e_tmp = qqrd2e/r * egamma;
} else {
f_tmp = qqrd2e/r * (derfc + EWALD_F*grij*expm2);
e_tmp = qqrd2e/r * derfc;
}
} else {
c_tmp = 0.0;
p_tmp = qqrd2e/r;
if (msmflag) {
f_tmp = qqrd2e/r * (fgamma - 1.0);
e_tmp = qqrd2e/r * egamma;
v_tmp = qqrd2e/r * fgamma;
} else {
f_tmp = qqrd2e/r * (derfc + EWALD_F*grij*expm2 - 1.0);
e_tmp = qqrd2e/r * derfc;
v_tmp = qqrd2e/r * (derfc + EWALD_F*grij*expm2);
}
if (rsq_lookup.f > cut_respa[2]*cut_respa[2]) {
if (rsq_lookup.f < cut_respa[3]*cut_respa[3]) {
rsw = (r - cut_respa[2])/(cut_respa[3] - cut_respa[2]);
f_tmp += qqrd2e/r * rsw*rsw*(3.0 - 2.0*rsw);
c_tmp = qqrd2e/r * rsw*rsw*(3.0 - 2.0*rsw);
} else {
if (msmflag) f_tmp = qqrd2e/r * fgamma;
else f_tmp = qqrd2e/r * (derfc + EWALD_F*grij*expm2);
c_tmp = qqrd2e/r;
}
}
}
drtable[itablemax] = 1.0/(rsq_lookup.f - rtable[itablemax]);
dftable[itablemax] = f_tmp - ftable[itablemax];
dctable[itablemax] = c_tmp - ctable[itablemax];
detable[itablemax] = e_tmp - etable[itablemax];
if (cut_respa) {
dvtable[itablemax] = v_tmp - vtable[itablemax];
dptable[itablemax] = p_tmp - ptable[itablemax];
}
}
}
/* ----------------------------------------------------------------------
free memory for tables used in pair computations
------------------------------------------------------------------------- */
void Pair::free_tables()
{
memory->destroy(rtable);
memory->destroy(drtable);
memory->destroy(ftable);
memory->destroy(dftable);
memory->destroy(ctable);
memory->destroy(dctable);
memory->destroy(etable);
memory->destroy(detable);
memory->destroy(vtable);
memory->destroy(dvtable);
memory->destroy(ptable);
memory->destroy(dptable);
}
/* ---------------------------------------------------------------------- /* ----------------------------------------------------------------------
mixing of pair potential prefactors (epsilon) mixing of pair potential prefactors (epsilon)
------------------------------------------------------------------------- */ ------------------------------------------------------------------------- */
@ -756,54 +989,6 @@ void Pair::ev_tally4(int i, int j, int k, int m, double evdwl,
} }
} }
/* ----------------------------------------------------------------------
tally ecoul and virial into each of n atoms in list
used to be called by TIP4P potential, newton_pair is always on
per-atom case changes v values by dividing them by n
------------------------------------------------------------------------- */
void Pair::ev_tally_list(int n, int *list, double ecoul, double *v)
{
int i,j;
if (eflag_either) {
if (eflag_global) eng_coul += ecoul;
if (eflag_atom) {
double epairatom = ecoul/n;
for (i = 0; i < n; i++) eatom[list[i]] += epairatom;
}
}
if (vflag_either) {
if (vflag_global) {
virial[0] += v[0];
virial[1] += v[1];
virial[2] += v[2];
virial[3] += v[3];
virial[4] += v[4];
virial[5] += v[5];
}
if (vflag_atom) {
v[0] /= n;
v[1] /= n;
v[2] /= n;
v[3] /= n;
v[4] /= n;
v[5] /= n;
for (i = 0; i < n; i++) {
j = list[i];
vatom[j][0] += v[0];
vatom[j][1] += v[1];
vatom[j][2] += v[2];
vatom[j][3] += v[3];
vatom[j][4] += v[4];
vatom[j][5] += v[5];
}
}
}
}
/* ---------------------------------------------------------------------- /* ----------------------------------------------------------------------
tally ecoul and virial into each of atoms in list tally ecoul and virial into each of atoms in list
called by TIP4P potential, newton_pair is always on called by TIP4P potential, newton_pair is always on

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@ -66,6 +66,10 @@ class Pair : protected Pointers {
int vflag_either,vflag_global,vflag_atom; int vflag_either,vflag_global,vflag_atom;
int ncoultablebits; // size of Coulomb table, accessed by KSpace int ncoultablebits; // size of Coulomb table, accessed by KSpace
double tabinnersq;
double *rtable,*drtable,*ftable,*dftable,*ctable,*dctable;
double *etable,*detable,*ptable,*dptable,*vtable,*dvtable;
int ncoulshiftbits,ncoulmask;
int nextra; // # of extra quantities pair style calculates int nextra; // # of extra quantities pair style calculates
double *pvector; // vector of extra pair quantities double *pvector; // vector of extra pair quantities
@ -130,6 +134,9 @@ class Pair : protected Pointers {
virtual void init_list(int, class NeighList *); virtual void init_list(int, class NeighList *);
virtual double init_one(int, int) {return 0.0;} virtual double init_one(int, int) {return 0.0;}
virtual void init_tables(double, double *);
virtual void free_tables();
virtual void write_restart(FILE *) {} virtual void write_restart(FILE *) {}
virtual void read_restart(FILE *) {} virtual void read_restart(FILE *) {}
virtual void write_restart_settings(FILE *) {} virtual void write_restart_settings(FILE *) {}
@ -179,7 +186,6 @@ class Pair : protected Pointers {
double, double, double, double, double, double); double, double, double, double, double, double);
void ev_tally4(int, int, int, int, double, void ev_tally4(int, int, int, int, double,
double *, double *, double *, double *, double *, double *); double *, double *, double *, double *, double *, double *);
void ev_tally_list(int, int *, double, double *);
void ev_tally_tip4p(int, int *, double *, double, double); void ev_tally_tip4p(int, int *, double *, double, double);
void v_tally2(int, int, double, double *); void v_tally2(int, int, double, double *);
void v_tally_tensor(int, int, int, int, void v_tally_tensor(int, int, int, int,