/* nag_sum_fft_real_3d (c06pyc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.0, 2024.
*/
#include <nag.h>
#include <stdio.h>
int main(void) {
/* Scalars */
Integer exit_status = 0, k, n1, n2, n3;
/* Arrays */
Complex *y = 0;
double *x = 0;
char title[30];
/* Nag Types */
NagError fail;
INIT_FAIL(fail);
printf("nag_sum_fft_real_3d (c06pyc) Example Program Results\n");
fflush(stdout);
/* Read dimensions of array from data file. */
scanf("%*[^\n] %" NAG_IFMT "%" NAG_IFMT "%" NAG_IFMT "%*[^\n]", &n1, &n2,
&n3);
if (!(x = NAG_ALLOC(n1 * n2 * n3, double)) ||
!(y = NAG_ALLOC((n1 / 2 + 1) * n2 * n3, Complex))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Read array values from data file and print out. */
for (k = 0; k < n1 * n2 * n3; k++)
scanf("%lf", &x[k]);
printf("\nBelow we define X(i,j,k)=x[k*n1*n2+j*n1+i]");
printf(" where i and j are the row and column \n");
printf("indices of the matrices printed.");
printf(" Y is defined similarly (but having n1/2+1 rows\n");
printf("only due to conjugate symmetry).\n");
printf("\n Original data values\n");
fflush(stdout);
for (k = 0; k < n3; k++) {
sprintf(title, "\n X(i,j,k) for k = %" NAG_IFMT, k);
nag_file_print_matrix_real_gen_comp(
Nag_ColMajor, Nag_GeneralMatrix, Nag_NonUnitDiag, n1, n2,
&x[k * n1 * n2], n1, "%6.3f", title, Nag_NoLabels, 0, Nag_NoLabels, 0,
80, 0, 0, &fail);
}
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_gen_comp (x04cbc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
/* Compute three-dimensional real-to-complex discrete Fourier transform using
* nag_sum_fft_real_3d (c06pyc) and print out.
*/
nag_sum_fft_real_3d(n1, n2, n3, x, y, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sum_fft_real_3d (c06pyc).\n%s\n", fail.message);
exit_status = 2;
goto END;
}
printf("\n Components of discrete Fourier transform\n");
fflush(stdout);
for (k = 0; k < n3; k++) {
sprintf(title, "\n Y(i,j,k) for k = %" NAG_IFMT, k);
/* nag_file_print_matrix_complex_gen_comp (x04dbc).
* Print complex general matrix (comprehensive) */
nag_file_print_matrix_complex_gen_comp(
Nag_ColMajor, Nag_GeneralMatrix, Nag_NonUnitDiag, n1 / 2 + 1, n2,
&y[k * (n1 / 2 + 1) * n2], n1 / 2 + 1, Nag_BracketForm, "%6.3f", title,
Nag_NoLabels, 0, Nag_NoLabels, 0, 90, 0, 0, &fail);
}
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_complex_gen_comp (x04dbc).\n%s\n",
fail.message);
exit_status = 3;
goto END;
}
/* Compute three-dimensional complex-to-real discrete Fourier transform using
* nag_sum_fft_hermitian_3d (c06pzc) and print out.
*/
nag_sum_fft_hermitian_3d(n1, n2, n3, y, x, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_sum_fft_hermitian_3d (c06pzc).\n%s\n", fail.message);
exit_status = 4;
goto END;
}
printf("\n Original sequence as restored by inverse transform\n");
fflush(stdout);
for (k = 0; k < n3; k++) {
sprintf(title, "\n X(i,j,k) for k = %" NAG_IFMT, k);
/* nag_file_print_matrix_real_gen_comp (x04cbc).
* Print out a real matrix (comprehensive) */
nag_file_print_matrix_real_gen_comp(
Nag_ColMajor, Nag_GeneralMatrix, Nag_NonUnitDiag, n1, n2,
&x[k * n1 * n2], n1, "%6.3f", title, Nag_NoLabels, 0, Nag_NoLabels, 0,
80, 0, 0, &fail);
}
if (fail.code != NE_NOERROR) {
printf("Error from nag_file_print_matrix_real_gen_comp (x04cbc).\n%s\n",
fail.message);
exit_status = 5;
goto END;
}
END:
NAG_FREE(x);
NAG_FREE(y);
return exit_status;
}