Files
lammps/tools/phonon/phonopy.cpp
2024-02-09 06:29:08 -05:00

329 lines
10 KiB
C++

#ifdef FFTW3
#include "phonopy.h"
#include "global.h"
#include "dynmat.h"
#include "input.h"
#include "memory.h"
#include <fftw3.h>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <map>
/* ----------------------------------------------------------------------------
* Class Phonopy is designed to interface with phonopy.
* ---------------------------------------------------------------------------- */
Phonopy::Phonopy(DynMat *dynmat)
{
dm = dynmat;
memory = new Memory();
sysdim = dm->sysdim;
fftdim = dm->fftdim;
input = dm->input;
fftdim2 = fftdim * fftdim;
nucell = dm->nucell;
nx = ny = nz = 5;
write(1);
char str[MAXLINE];
if (input == NULL) input = new UserInput(0);
input->read_stdin(str);
if (count_words(str) >= 3){
nx = atoi(strtok(str," \t\n\r\f"));
ny = atoi(strtok(NULL," \t\n\r\f"));
nz = atoi(strtok(NULL," \t\n\r\f"));
}
if (dm->nx == 1) nx = 1;
if (dm->ny == 1) ny = 1;
if (dm->nz == 1) nz = 1;
if (nx < 1) nx = 1;
if (ny < 1) ny = 1;
if (nz < 1) nz = 1;
npt = nx * ny * nz;
write(2);
memory->create(mass, nucell, "Phonopy:mass");
for (int i = 0; i < nucell; ++i){
double m = 1.0/dm->M_inv_sqrt[i];
mass[i] = m * m;
}
memory->create(FC_all, npt, fftdim2, "phonopy:FC_all");
get_my_FC();
phonopy();
}
/* ----------------------------------------------------------------------------
* Deconstructor, free the memory used.
* ---------------------------------------------------------------------------- */
Phonopy::~Phonopy()
{
memory->destroy(mass);
memory->destroy(FC_all);
delete memory;
dm = nullptr;
}
/* ----------------------------------------------------------------------------
* Subroutine to write the outputs to screen.
* ---------------------------------------------------------------------------- */
void Phonopy::write(int flag)
{
if (flag == 1){ // basic information
puts("================================================================================");
printf("Now to prepare the input files for phonopy.\n");
printf("The dimension of your present supercell is : %d x %d x %d.\n", dm->nx, dm->ny, dm->nz);
printf("The size of the force constant matrix will be: %d x %d.\n", dm->npt*3, dm->npt*3);
printf("Please define your desired dimension [5 5 5] : ");
} else if (flag == 2){
printf("\nThe new dimension of the supercell will be : %d x %d x %d.\n", nx, ny, nz);
printf("The size of the force constant matrix is then: %d x %d.\n", npt*3, npt*3);
} else if (flag == 3){
printf("\nNow to prepare the phonopy FORCE_CONSTANTS ..."); fflush(stdout);
} else if (flag == 4){
printf("Done!\nThe force constants information is extracted and written to FORCE_CONSTANTS,\n");
printf("the primitive cell is written to POSCAR.primitive, and the input file for\n");
printf("phonopy band evaluation is written to band.conf.\n\n");
printf("One should be able to obtain the phonon band structure after\n");
printf(" 1) Correcting the `element names` in POSCAR.primitive and band.conf;\n");
printf(" 2) Running `phonopy --readfc -c POSCAR.primitive -p band.conf`.\n\n");
printf("Or the phonon density of states after\n");
printf(" 1) Correcting the `element names` in POSCAR.primitive and mesh.conf;\n");
printf(" 2) Running `phonopy --readfc -c POSCAR.primitive -p mesh.conf`.\n");
puts("--------------------------------------------------------------------------------");
printf("*** Remember to modify the `element names`. ***\n");
} else if (flag == 5){
puts("================================================================================");
}
}
/* ----------------------------------------------------------------------------
* Driver to obtain the force constant matrix
* ---------------------------------------------------------------------------- */
void Phonopy::get_my_FC()
{
double q[3];
int ipt = 0;
for (int ix = 0; ix < nx; ++ix)
for (int iy = 0; iy < ny; ++iy)
for (int iz = 0; iz < nz; ++iz){
q[0] = double(ix)/double(nx);
q[1] = double(iy)/double(ny);
q[2] = double(iz)/double(nz);
dm->getDMq(q);
int ndim = 0;
for (int idim = 0; idim < fftdim; ++idim)
for (int jdim = 0; jdim < fftdim; ++jdim){
FC_all[ipt][ndim] = dm->DM_q[idim][jdim];
double m = sqrt(mass[idim/sysdim] * mass[jdim/sysdim]);
FC_all[ipt][ndim].r *= m;
FC_all[ipt][ndim].i *= m;
++ndim;
}
++ipt;
}
}
/* ----------------------------------------------------------------------------
* Method to write out the force constants and related files for
* postprocessing with phonopy.
* ---------------------------------------------------------------------------- */
void Phonopy::phonopy()
{
// output info
write(3);
fftw_complex *in, *out;
double **fc;
memory->create(in, npt, "phonopy:in");
memory->create(out, npt, "phonopy:in");
memory->create(fc, npt, fftdim2, "phonopy:in");
fftw_plan plan = fftw_plan_dft_3d(nx, ny, nz, in, out, -1, FFTW_ESTIMATE);
double factor = dm->eml2fc / double(npt);
for (int idim = 0; idim < fftdim2; ++idim){
for (int i = 0; i < npt; ++i){
in[i][0] = FC_all[i][idim].r;
in[i][1] = FC_all[i][idim].i;
}
fftw_execute(plan);
for (int i = 0; i < npt; ++i) fc[i][idim] = out[i][0] * factor;
}
fftw_destroy_plan(plan);
memory->destroy(in);
memory->destroy(out);
// in POSCAR, atoms are sorted/aggregated by type, while for LAMMPS there is no such requirment
int *type_id = new int[nucell];
int *num_type = new int[nucell];
int ntype = 0;
for (int i = 0; i < nucell; ++i) num_type[i] = 0;
for (int i = 0; i < nucell; ++i){
int ip = ntype;
for (int j = 0; j < ntype; ++j){
if (dm->attyp[i] == type_id[j]) ip = j;
}
if (ip == ntype) type_id[ntype++] = dm->attyp[i];
num_type[ip]++;
}
std::map<int, int> iu_by_type;
iu_by_type.clear();
int id_new = 0;
for (int i = 0; i < ntype; ++i){
for (int j = 0; j < nucell; ++j){
if (dm->attyp[j] == type_id[i]) iu_by_type[id_new++] = j;
}
}
// write the FORCE_CONSTANTS file
FILE *fp = fopen("FORCE_CONSTANTS", "w");
int natom = npt * nucell;
fprintf(fp, "%d %d\n", natom, natom);
for (int i = 0; i < natom; ++i){
int iu = i / npt;
int iz = (i % npt) / (nx * ny);
int iy = (i % (nx *ny) ) / nx;
int ix = i % nx;
iu = iu_by_type[iu];
for (int j = 0; j < natom; ++j){
int ju = j / npt;
int jz = (j % npt) / (nx * ny);
int jy = (j % (nx *ny) ) / nx;
int jx = j % nx;
int dx = abs(ix - jx);
int dy = abs(iy - jy);
int dz = abs(iz - jz);
int id = (dx * ny + dy) * nz + dz;
ju = iu_by_type[ju];
fprintf(fp, "%d %d\n", i+1, j+1);
for (int idim = iu * sysdim; idim < (iu+1)*sysdim; ++idim){
for (int jdim = ju * sysdim; jdim < (ju+1)*sysdim; ++jdim){
int dd = idim * fftdim + jdim;
fprintf(fp, " %lg", fc[id][dd]);
}
fprintf(fp, "\n");
}
}
}
fclose(fp);
iu_by_type.clear();
memory->destroy(fc);
// write the primitive cell in POSCAR format
fp = fopen("POSCAR.primitive", "w");
fprintf(fp, "Fix-phonon unit cell");
for (int ip = 0; ip < ntype; ++ip){
for (int i = 0; i < nucell; ++i){
if (dm->attyp[i] == type_id[ip]){
fprintf(fp, ", Elem-%d: %lg", type_id[ip], mass[i]);
break;
}
}
}
fprintf(fp, "\n1.\n");
int ndim = 0;
for (int idim = 0; idim < 3; ++idim){
for (int jdim = 0; jdim < 3; ++jdim) fprintf(fp, "%lg ", dm->basevec[ndim++]);
fprintf(fp, "\n");
}
for (int ip = 0; ip < ntype; ++ip) fprintf(fp, "Elem-%d ", type_id[ip]);
fprintf(fp, "\n");
for (int ip = 0; ip < ntype; ++ip) fprintf(fp, "%d ", num_type[ip]);
fprintf(fp, "\nDirect\n");
for (int ip = 0; ip < ntype; ++ip){
for (int i = 0; i < nucell; ++i){
if (dm->attyp[i] == type_id[ip]){
fprintf(fp, "%lg %lg %lg\n", dm->basis[i][0], dm->basis[i][1], dm->basis[i][2]);
}
}
}
fclose(fp);
// mesh.conf
fp = fopen("mesh.conf", "w");
fprintf(fp, "# From Fix-phonon");
for (int ip = 0; ip < ntype; ++ip){
for (int i = 0; i < nucell; ++i){
if (dm->attyp[i] == type_id[ip]){
fprintf(fp, ", Elem-%d: %lg", type_id[ip], mass[i]);
break;
}
}
}
fprintf(fp, "\n\nATOM_NAME = ");
for (int ip = 0; ip < ntype; ++ip) fprintf(fp, "Elem-%d ", type_id[ip]);
fprintf(fp, "\nDIM = %d %d %d\n", nx, ny, nz);
fprintf(fp, "MP = 31 31 31\nFORCE_CONSTANTS = READ\n");
fprintf(fp, "#FC_SYMMETRY = .TRUE.\n#SYMMETRY_TOLERANCE = 0.01\n");
fclose(fp);
// band.conf
fp = fopen("band.conf", "w");
fprintf(fp, "# From Fix-phonon");
for (int ip = 0; ip < ntype; ++ip){
for (int i = 0; i < nucell; ++i){
if (dm->attyp[i] == type_id[ip]){
fprintf(fp, ", Elem-%d: %lg", type_id[ip], mass[i]);
break;
}
}
}
fprintf(fp, "\n\nATOM_NAME = ");
for (int ip = 0; ip < ntype; ++ip) fprintf(fp, "Elem-%d ", type_id[ip]);
fprintf(fp, "\nDIM = %d %d %d\nBAND = AUTO\n", nx, ny, nz);
fprintf(fp, "BAND_POINTS = 21\nFORCE_CONSTANTS = READ\nBAND_CONNECTION = .TRUE.\n");
fprintf(fp, "#FC_SYMMETRY = .TRUE.\n#SYMMETRY_TOLERANCE = 0.01\n");
// output info
write(4);
write(5);
delete[] type_id;
delete[] num_type;
}
/*------------------------------------------------------------------------------
* Method to count # of words in a string, without destroying the string
*----------------------------------------------------------------------------*/
int Phonopy::count_words(const char *line)
{
int n = strlen(line) + 1;
char *copy;
memory->create(copy, n, "count_words:copy");
strcpy(copy,line);
char *ptr;
if ((ptr = strchr(copy,'#'))) *ptr = '\0';
if (strtok(copy," \t\n\r\f") == NULL) {
memory->destroy(copy);
return 0;
}
n = 1;
while (strtok(NULL," \t\n\r\f")) n++;
memory->destroy(copy);
return n;
}
/*----------------------------------------------------------------------------*/
#endif