Files
lammps/src/AMOEBA/angle_amoeba.cpp
2021-10-19 16:10:51 -06:00

531 lines
15 KiB
C++

// clang-format off
/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
https://www.lammps.org/, 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 "angle_amoeba.h"
#include <cmath>
#include <cstring>
#include "atom.h"
#include "neighbor.h"
#include "domain.h"
#include "comm.h"
#include "force.h"
#include "math_const.h"
#include "memory.h"
#include "error.h"
using namespace LAMMPS_NS;
using namespace MathConst;
#define SMALL 0.001
/* ---------------------------------------------------------------------- */
AngleAmoeba::AngleAmoeba(LAMMPS *lmp) : Angle(lmp)
{
pflag = nullptr;
theta0 = nullptr;
k2 = nullptr;
k3 = nullptr;
k4 = nullptr;
k5 = nullptr;
k6 = nullptr;
}
/* ---------------------------------------------------------------------- */
AngleAmoeba::~AngleAmoeba()
{
if (copymode) return;
if (allocated) {
memory->destroy(setflag);
memory->destroy(pflag);
memory->destroy(theta0);
memory->destroy(k2);
memory->destroy(k3);
memory->destroy(k4);
memory->destroy(k5);
memory->destroy(k6);
}
}
/* ---------------------------------------------------------------------- */
void AngleAmoeba::compute(int eflag, int vflag)
{
int i1,i2,i3,n,type,tflag;
double delx1,dely1,delz1,delx2,dely2,delz2;
double eangle,f1[3],f3[3];
double dtheta,dtheta2,dtheta3,dtheta4,dtheta5,dtheta6,de_angle;
double dr1,dr2,tk1,tk2,aa1,aa2,aa11,aa12,aa21,aa22;
double rsq1,rsq2,r1,r2,c,s,a,a11,a12,a22,b1,b2;
eangle = 0.0;
ev_init(eflag,vflag);
double **x = atom->x;
double **f = atom->f;
int **anglelist = neighbor->anglelist;
int **nspecial = atom->nspecial;
int nanglelist = neighbor->nanglelist;
int nlocal = atom->nlocal;
int newton_bond = force->newton_bond;
for (n = 0; n < nanglelist; n++) {
i1 = anglelist[n][0];
i2 = anglelist[n][1];
i3 = anglelist[n][2];
type = anglelist[n][3];
// tflag = 0 for "angle", 1 for "anglep" in Tinker PRM file
// atom 2 must have 3 bond partners to invoke anglep() variant
tflag = pflag[type];
if (tflag && nspecial[i2][0] == 3) {
anglep(i1,i2,i3,type,eflag);
continue;
}
// 1st bond
delx1 = x[i1][0] - x[i2][0];
dely1 = x[i1][1] - x[i2][1];
delz1 = x[i1][2] - x[i2][2];
rsq1 = delx1*delx1 + dely1*dely1 + delz1*delz1;
r1 = sqrt(rsq1);
// 2nd bond
delx2 = x[i3][0] - x[i2][0];
dely2 = x[i3][1] - x[i2][1];
delz2 = x[i3][2] - x[i2][2];
rsq2 = delx2*delx2 + dely2*dely2 + delz2*delz2;
r2 = sqrt(rsq2);
// angle (cos and sin)
c = delx1*delx2 + dely1*dely2 + delz1*delz2;
c /= r1*r2;
if (c > 1.0) c = 1.0;
if (c < -1.0) c = -1.0;
s = sqrt(1.0 - c*c);
if (s < SMALL) s = SMALL;
s = 1.0/s;
// force & energy for angle term
dtheta = acos(c) - theta0[type];
dtheta2 = dtheta*dtheta;
dtheta3 = dtheta2*dtheta;
dtheta4 = dtheta3*dtheta;
dtheta5 = dtheta4*dtheta;
dtheta6 = dtheta5*dtheta;
de_angle = 2.0*k2[type]*dtheta + 3.0*k3[type]*dtheta2 +
4.0*k4[type]*dtheta3 + 5.0*k5[type]*dtheta4 + 6.0*k6[type]*dtheta5;
a = -de_angle*s;
a11 = a*c / rsq1;
a12 = -a / (r1*r2);
a22 = a*c / rsq2;
f1[0] = a11*delx1 + a12*delx2;
f1[1] = a11*dely1 + a12*dely2;
f1[2] = a11*delz1 + a12*delz2;
f3[0] = a22*delx2 + a12*delx1;
f3[1] = a22*dely2 + a12*dely1;
f3[2] = a22*delz2 + a12*delz1;
if (eflag) eangle = k2[type]*dtheta2 + k3[type]*dtheta3 +
k4[type]*dtheta4 + k5[type]*dtheta5 + k6[type]*dtheta6;
// apply force to each of 3 atoms
if (newton_bond || i1 < nlocal) {
f[i1][0] += f1[0];
f[i1][1] += f1[1];
f[i1][2] += f1[2];
}
if (newton_bond || i2 < nlocal) {
f[i2][0] -= f1[0] + f3[0];
f[i2][1] -= f1[1] + f3[1];
f[i2][2] -= f1[2] + f3[2];
}
if (newton_bond || i3 < nlocal) {
f[i3][0] += f3[0];
f[i3][1] += f3[1];
f[i3][2] += f3[2];
}
if (evflag) ev_tally(i1,i2,i3,nlocal,newton_bond,eangle,f1,f3,
delx1,dely1,delz1,delx2,dely2,delz2);
}
}
/* ---------------------------------------------------------------------- */
void AngleAmoeba::anglep(int i1, int i2, int i3, int type, int eflag)
{
int i4;
tagint i1tag,i3tag,i4tag;
double xia,yia,zia,xib,yib,zib,xic,yic,zic,xid,yid,zid;
double xad,yad,zad,xbd,ybd,zbd,xcd,ycd,zcd;
double xt,yt,zt,rt2;
double xip,yip,zip,xap,yap,zap,xcp,ycp,zcp;
double rap2,rcp2;
double dtheta,dtheta2,dtheta3,dtheta4,dtheta5,dtheta6;
double xm,ym,zm,rm,dot;
double cosine,angle;
double eangle,deddt;
double dedxip,dedyip,dedzip,dpdxia,dpdyia,dpdzia,dpdxic,dpdyic,dpdzic;
double delta,delta2,ptrt2,term,terma,termc;
double f1[3],f2[3],f3[3],f4[3];
double **x = atom->x;
double **f = atom->f;
tagint **special = atom->special;
int nlocal = atom->nlocal;
int newton_bond = force->newton_bond;
// i4 = index of third atom that i2 is bonded to
i1tag = atom->tag[i1];
i3tag = atom->tag[i3];
for (int ibond = 0; ibond < 3; ibond++) {
i4tag = special[i2][ibond];
if (i4tag != i1tag && i4tag != i3tag) break;
}
i4 = atom->map(i4tag);
i4 = domain->closest_image(i2,i4);
// anglep out-of-plane calculation from Tinker
xia = x[i1][0];
yia = x[i1][1];
zia = x[i1][2];
xib = x[i2][0];
yib = x[i2][1];
zib = x[i2][2];
xic = x[i3][0];
yic = x[i3][1];
zic = x[i3][2];
xid = x[i4][0];
yid = x[i4][1];
zid = x[i4][2];
xad = xia - xid;
yad = yia - yid;
zad = zia - zid;
xbd = xib - xid;
ybd = yib - yid;
zbd = zib - zid;
xcd = xic - xid;
ycd = yic - yid;
zcd = zic - zid;
xt = yad*zcd - zad*ycd;
yt = zad*xcd - xad*zcd;
zt = xad*ycd - yad*xcd;
rt2 = xt*xt + yt*yt + zt*zt;
delta = -(xt*xbd + yt*ybd + zt*zbd) / rt2;
xip = xib + xt*delta;
yip = yib + yt*delta;
zip = zib + zt*delta;
xap = xia - xip;
yap = yia - yip;
zap = zia - zip;
xcp = xic - xip;
ycp = yic - yip;
zcp = zic - zip;
rap2 = xap*xap + yap*yap + zap*zap;
rcp2 = xcp*xcp + ycp*ycp + zcp*zcp;
// NOTE: can these be 0.0 ? what to do?
if (rap2 == 0.0 || rcp2 == 0.0) return;
xm = ycp*zap - zcp*yap;
ym = zcp*xap - xcp*zap;
zm = xcp*yap - ycp*xap;
rm = sqrt(xm*xm + ym*ym + zm*zm);
rm = MAX(rm,0.0001);
dot = xap*xcp + yap*ycp + zap*zcp;
cosine = dot / sqrt(rap2*rcp2);
cosine = MIN(1.0,MAX(-1.0,cosine));
// force & energy for angle term
dtheta = acos(cosine) - theta0[type];
dtheta2 = dtheta*dtheta;
dtheta3 = dtheta2*dtheta;
dtheta4 = dtheta3*dtheta;
dtheta5 = dtheta4*dtheta;
dtheta6 = dtheta5*dtheta;
deddt = 2.0*k2[type]*dtheta + 3.0*k3[type]*dtheta2 +
4.0*k4[type]*dtheta3 + 5.0*k5[type]*dtheta4 + 6.0*k6[type]*dtheta5;
if (eflag) eangle = k2[type]*dtheta2 + k3[type]*dtheta3 +
k4[type]*dtheta4 + k5[type]*dtheta5 + k6[type]*dtheta6;
// chain rule terms for first derivative components
terma = -deddt / (rap2*rm);
termc = deddt / (rcp2*rm);
f1[0] = terma * (yap*zm-zap*ym);
f1[1] = terma * (zap*xm-xap*zm);
f1[2] = terma * (xap*ym-yap*xm);
f3[0] = termc * (ycp*zm-zcp*ym);
f3[1] = termc * (zcp*xm-xcp*zm);
f3[2] = termc * (xcp*ym-ycp*xm);
dedxip = -f1[0] - f3[0];
dedyip = -f1[1] - f3[1];
dedzip = -f1[2] - f3[2];
// chain rule components for the projection of the central atom
delta2 = 2.0 * delta;
ptrt2 = (dedxip*xt + dedyip*yt + dedzip*zt) / rt2;
term = (zcd*ybd-ycd*zbd) + delta2*(yt*zcd-zt*ycd);
dpdxia = delta*(ycd*dedzip-zcd*dedyip) + term*ptrt2;
term = (xcd*zbd-zcd*xbd) + delta2*(zt*xcd-xt*zcd);
dpdyia = delta*(zcd*dedxip-xcd*dedzip) + term*ptrt2;
term = (ycd*xbd-xcd*ybd) + delta2*(xt*ycd-yt*xcd);
dpdzia = delta*(xcd*dedyip-ycd*dedxip) + term*ptrt2;
term = (yad*zbd-zad*ybd) + delta2*(zt*yad-yt*zad);
dpdxic = delta*(zad*dedyip-yad*dedzip) + term*ptrt2;
term = (zad*xbd-xad*zbd) + delta2*(xt*zad-zt*xad);
dpdyic = delta*(xad*dedzip-zad*dedxip) + term*ptrt2;
term = (xad*ybd-yad*xbd) + delta2*(yt*xad-xt*yad);
dpdzic = delta*(yad*dedxip-xad*dedyip) + term*ptrt2;
// compute derivative components for this interaction
f1[0] += dpdxia;
f1[1] += dpdyia;
f1[2] += dpdzia;
f2[0] = dedxip;
f2[1] = dedyip;
f2[2] = dedzip;
f3[0] += dpdxic;
f3[1] += dpdyic;
f3[2] += dpdzic;
f4[0] = -f1[0] - f2[0] - f3[0];
f4[1] = -f1[1] - f2[1] - f3[1];
f4[2] = -f1[2] - f2[2] - f3[2];
// apply force to each of 4 atoms
if (newton_bond || i1 < nlocal) {
f[i1][0] += f1[0];
f[i1][1] += f1[1];
f[i1][2] += f1[2];
}
if (newton_bond || i2 < nlocal) {
f[i2][0] += f2[0];
f[i2][1] += f2[1];
f[i2][2] += f2[2];
}
if (newton_bond || i3 < nlocal) {
f[i3][0] += f3[0];
f[i3][1] += f3[1];
f[i3][2] += f3[2];
}
if (newton_bond || i4 < nlocal) {
f[i4][0] += f4[0];
f[i4][1] += f4[1];
f[i4][2] += f4[2];
}
if (evflag) ev_tally4(i1,i2,i3,14,nlocal,newton_bond,eangle,f1,f2,f3,f4);
}
/* ---------------------------------------------------------------------- */
void AngleAmoeba::allocate()
{
allocated = 1;
int n = atom->nangletypes;
memory->create(pflag,n+1,"angle:pflag");
memory->create(theta0,n+1,"angle:theta0");
memory->create(k2,n+1,"angle:k2");
memory->create(k3,n+1,"angle:k3");
memory->create(k4,n+1,"angle:k4");
memory->create(k5,n+1,"angle:k5");
memory->create(k6,n+1,"angle:k6");
memory->create(setflag,n+1,"angle:setflag");
for (int i = 1; i <= n; i++) setflag[i] = 0;
}
/* ----------------------------------------------------------------------
set coeffs for one or more types
------------------------------------------------------------------------- */
void AngleAmoeba::coeff(int narg, char **arg)
{
if (!allocated) allocate();
int ilo,ihi;
utils::bounds(FLERR,arg[0],1,atom->nangletypes,ilo,ihi,error);
int count = 0;
if (narg != 8) error->all(FLERR,"Incorrect args for angle coefficients");
int pflag_one = utils::inumeric(FLERR,arg[1],false,lmp);
double theta0_one = utils::numeric(FLERR,arg[2],false,lmp);
double k2_one = utils::numeric(FLERR,arg[3],false,lmp);
double k3_one = utils::numeric(FLERR,arg[4],false,lmp);
double k4_one = utils::numeric(FLERR,arg[5],false,lmp);
double k5_one = utils::numeric(FLERR,arg[6],false,lmp);
double k6_one = utils::numeric(FLERR,arg[7],false,lmp);
// convert theta0 from degrees to radians
for (int i = ilo; i <= ihi; i++) {
pflag[i] = pflag_one;
theta0[i] = theta0_one/180.0 * MY_PI;
k2[i] = k2_one;
k3[i] = k3_one;
k4[i] = k4_one;
k5[i] = k5_one;
k6[i] = k6_one;
count++;
}
if (count == 0) error->all(FLERR,"Incorrect args for angle coefficients");
for (int i = ilo; i <= ihi; i++) setflag[i] = 1;
}
/* ---------------------------------------------------------------------- */
double AngleAmoeba::equilibrium_angle(int i)
{
return theta0[i];
}
/* ----------------------------------------------------------------------
proc 0 writes out coeffs to restart file
------------------------------------------------------------------------- */
void AngleAmoeba::write_restart(FILE *fp)
{
fwrite(&pflag[1],sizeof(int),atom->nangletypes,fp);
fwrite(&theta0[1],sizeof(double),atom->nangletypes,fp);
fwrite(&k2[1],sizeof(double),atom->nangletypes,fp);
fwrite(&k3[1],sizeof(double),atom->nangletypes,fp);
fwrite(&k4[1],sizeof(double),atom->nangletypes,fp);
fwrite(&k5[1],sizeof(double),atom->nangletypes,fp);
fwrite(&k6[1],sizeof(double),atom->nangletypes,fp);
}
/* ----------------------------------------------------------------------
proc 0 reads coeffs from restart file, bcasts them
------------------------------------------------------------------------- */
void AngleAmoeba::read_restart(FILE *fp)
{
allocate();
if (comm->me == 0) {
utils::sfread(FLERR,&pflag[1],sizeof(int),atom->nangletypes,fp,nullptr,error);
utils::sfread(FLERR,&theta0[1],sizeof(double),atom->nangletypes,fp,nullptr,error);
utils::sfread(FLERR,&k2[1],sizeof(double),atom->nangletypes,fp,nullptr,error);
utils::sfread(FLERR,&k3[1],sizeof(double),atom->nangletypes,fp,nullptr,error);
utils::sfread(FLERR,&k4[1],sizeof(double),atom->nangletypes,fp,nullptr,error);
utils::sfread(FLERR,&k5[1],sizeof(double),atom->nangletypes,fp,nullptr,error);
utils::sfread(FLERR,&k6[1],sizeof(double),atom->nangletypes,fp,nullptr,error);
}
MPI_Bcast(&pflag[1],atom->nangletypes,MPI_INT,0,world);
MPI_Bcast(&theta0[1],atom->nangletypes,MPI_DOUBLE,0,world);
MPI_Bcast(&k2[1],atom->nangletypes,MPI_DOUBLE,0,world);
MPI_Bcast(&k3[1],atom->nangletypes,MPI_DOUBLE,0,world);
MPI_Bcast(&k4[1],atom->nangletypes,MPI_DOUBLE,0,world);
MPI_Bcast(&k5[1],atom->nangletypes,MPI_DOUBLE,0,world);
MPI_Bcast(&k6[1],atom->nangletypes,MPI_DOUBLE,0,world);
for (int i = 1; i <= atom->nangletypes; i++) setflag[i] = 1;
}
/* ----------------------------------------------------------------------
proc 0 writes to data file
------------------------------------------------------------------------- */
void AngleAmoeba::write_data(FILE *fp)
{
for (int i = 1; i <= atom->nangletypes; i++)
fprintf(fp,"%d %d %g %g %g %g %g %g\n",
i,pflag[i],theta0[i]/MY_PI*180.0,k2[i],k3[i],k4[i],k5[i],k6[i]);
}
/* ---------------------------------------------------------------------- */
double AngleAmoeba::single(int type, int i1, int i2, int i3)
{
double **x = atom->x;
double delx1 = x[i1][0] - x[i2][0];
double dely1 = x[i1][1] - x[i2][1];
double delz1 = x[i1][2] - x[i2][2];
domain->minimum_image(delx1,dely1,delz1);
double r1 = sqrt(delx1*delx1 + dely1*dely1 + delz1*delz1);
double delx2 = x[i3][0] - x[i2][0];
double dely2 = x[i3][1] - x[i2][1];
double delz2 = x[i3][2] - x[i2][2];
domain->minimum_image(delx2,dely2,delz2);
double r2 = sqrt(delx2*delx2 + dely2*dely2 + delz2*delz2);
double c = delx1*delx2 + dely1*dely2 + delz1*delz2;
c /= r1*r2;
if (c > 1.0) c = 1.0;
if (c < -1.0) c = -1.0;
double s = sqrt(1.0 - c*c);
if (s < SMALL) s = SMALL;
s = 1.0/s;
double dtheta = acos(c) - theta0[type];
double dtheta2 = dtheta*dtheta;
double dtheta3 = dtheta2*dtheta;
double dtheta4 = dtheta3*dtheta;
double dtheta5 = dtheta4*dtheta;
double dtheta6 = dtheta5*dtheta;
double energy = k2[type]*dtheta2 + k3[type]*dtheta3 + k4[type]*dtheta4
+ k5[type]*dtheta5 + k6[type]*dtheta6;
return energy;
}