/*--------------------*/
void
spg_get_tetrahedra_relative_grid_address(int relative_grid_address[24][4][3],
SPGCONST double rec_lattice[3][3])
{
thm_get_relative_grid_address(relative_grid_address, rec_lattice);
}
/* (http://phonopy.sf.net/) */
static void test_tetrahedron_method(void)
{
printf("*** Example of tetrahedron method of NaCl to calculate DOS ***:\n");
printf("Read data from frequency.dat and write DOS to dos.dat.\n");
int i, j, k, l, q, r;
/* NaCl 20x20x20 mesh */
double lattice[3][3] = {
{0.000000000000000, 2.845150738087836, 2.845150738087836},
{2.845150738087836, 0.000000000000000, 2.845150738087836},
{2.845150738087836, 2.845150738087836, 0.000000000000000}
};
double position[][3] =
{{0, 0, 0},
{0.5, 0.5, 0.5}};
int types[] = {1, 2};
int num_atom = 2;
int m = 20;
int mesh[] = {m, m, m};
int num_gp = mesh[0] * mesh[1] * mesh[2];
int is_shift[] = {0, 0, 0};
int grid_address[num_gp][3];
int grid_mapping_table[num_gp];
int weights[num_gp];
int num_ir = spg_get_ir_reciprocal_mesh(grid_address,
grid_mapping_table,
mesh,
is_shift,
1,
lattice,
position,
types,
num_atom,
1e-5);
int ir_gp[num_ir];
int ir_weights[num_ir];
int gp_ir_index[num_gp];
int relative_grid_address[24][4][3];
double rec_lat[3][3];
FILE *fp;
char * line = NULL;
size_t len = 0;
ssize_t read;
double frequency[num_ir * num_atom * 3];
double max_f, min_f;
double t_omegas[24][4];
int g_addr[3];
int gp;
int num_freqs = 201;
double dos[num_freqs];
double integral_dos[num_freqs];
double omegas[num_freqs];
double iw;
for (i = 0; i < num_gp; i++) {
weights[i] = 0;
}
for (i = 0; i < num_gp; i++) {
weights[grid_mapping_table[i]]++;
}
j = 0;
for (i = 0; i < num_gp; i++) {
if (weights[i] != 0) {
ir_gp[j] = i;
ir_weights[j] = weights[i];
gp_ir_index[i] = j;
j++;
} else {
gp_ir_index[i] = gp_ir_index[grid_mapping_table[i]];
}
}
printf("Number of irreducible k-points: %d\n", num_ir);
mat_inverse_matrix_d3(rec_lat, lattice, 1e-5);
thm_get_relative_grid_address(relative_grid_address, rec_lat);
/* for (i = 0; i < 24; i++) { */
/* for (j = 0; j < 4; j++) { */
/* printf("[%2d %2d %2d] ", */
/* relative_grid_address[i][j][0], */
/* relative_grid_address[i][j][1], */
/* relative_grid_address[i][j][2]); */
/* } */
/* printf("\n"); */
/* } */
fp = fopen("frequency.dat", "r");
for (i = 0; i < num_ir * num_atom * 3; i++) {
read = getline(&line, &len, fp);
if (read == -1) {
break;
}
frequency[i] = strtod(line, NULL);
}
fclose(fp);
max_f = frequency[0];
min_f = frequency[0];
for (i = 0; i < num_ir * num_atom * 3; i++) {
if (max_f < frequency[i]) {
max_f = frequency[i];
}
if (min_f > frequency[i]) {
min_f = frequency[i];
}
}
printf("Number of frequencies: %d\n", i);
#pragma omp parallel for private(j, k, l, q, r, g_addr, gp, t_omegas, iw)
for (i = 0; i < num_freqs; i++) {
dos[i] = 0;
integral_dos[i] = 0;
omegas[i] = min_f + (max_f - min_f) / (num_freqs - 1) * i;
for (j = 0; j < num_ir; j++) {
for (k = 0; k < num_atom * 3; k++) {
for (l = 0; l < 24; l++) {
for (q = 0; q < 4; q++) {
for (r = 0; r < 3; r++) {
g_addr[r] = grid_address[ir_gp[j]][r] +
relative_grid_address[l][q][r];
}
gp = spg_get_grid_point_from_address(g_addr, mesh);
t_omegas[l][q] = frequency[gp_ir_index[gp] * num_atom * 3 + k];
}
}
iw = thm_get_integration_weight(omegas[i], t_omegas, 'J');
dos[i] += iw * ir_weights[j];
iw = thm_get_integration_weight(omegas[i], t_omegas, 'I');
integral_dos[i] += iw * ir_weights[j];
}
}
}
fp = fopen("dos.dat", "w");
for (i = 0; i < num_freqs; i++) {
fprintf(fp, "%f %f\n", omegas[i], dos[i] / num_gp);
}
fprintf(fp, "\n\n");
for (i = 0; i < num_freqs; i++) {
fprintf(fp, "%f %f\n", omegas[i], integral_dos[i] / num_gp);
}
fclose(fp);
}
