/* nag_zpstrf (f07krc) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.1, 2017.
*/
#include <nag.h>
#include <nag_stdlib.h>
#include <naga02.h>
#include <nagf07.h>
#include <nagx04.h>
int main(void)
{
/* Scalars */
Integer exit_status = 0;
Integer i, j, n, pda, rank;
double tol;
/* Arrays */
Complex *a = 0;
Integer *piv = 0;
char nag_enum_arg[40];
/* Nag Types */
Nag_UploType uplo;
Nag_OrderType order;
Nag_MatrixType matrix;
NagError fail;
INIT_FAIL(fail);
printf("nag_zpstrf (f07krc) Example Program Results\n");
/* Skip heading in data file and retrieve data */
scanf("%*[^\n]%" NAG_IFMT "%39s%*[^\n]", &n, nag_enum_arg);
uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg);
if (!(a = NAG_ALLOC(n * n, Complex)) || !(piv = NAG_ALLOC(n, Integer)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
pda = n;
#ifdef NAG_COLUMN_MAJOR
order = Nag_ColMajor;
#define A(I, J) a[(J-1)*pda + I-1]
#else
order = Nag_RowMajor;
#define A(I, J) a[(I-1)*pda + J-1]
#endif
/* Read triangular part of A from data file */
if (uplo == Nag_Upper) {
matrix = Nag_UpperMatrix;
for (i = 1; i <= n; i++)
for (j = i; j <= n; j++)
scanf(" ( %lf , %lf ) ", &A(i, j).re, &A(i, j).im);
}
else if (uplo == Nag_Lower) {
matrix = Nag_LowerMatrix;
for (i = 1; i <= n; i++)
for (j = 1; j <= i; j++)
scanf(" ( %lf , %lf ) ", &A(i, j).re, &A(i, j).im);
}
else {
printf("Invalid uplo.\n");
exit_status = 1;
goto END;
}
scanf("%*[^\n]");
tol = -1.0;
/* Factorize A using nag_zpstrf (f07krc) which performs a Cholesky
* factorization of complex Hermitian positive semidefinite matrix.
*/
nag_zpstrf(order, uplo, n, a, pda, piv, &rank, tol, &fail);
if (fail.code == NW_NOT_POS_DEF) {
/* A is not of full rank.
* Zero out columns rank+1 to n.
*/
if (uplo == Nag_Upper)
for (j = rank + 1; j <= n; j++)
for (i = rank + 1; i <= j; i++)
A(i, j) = nag_complex(0.0, 0.0);
else if (uplo == Nag_Lower)
for (j = rank + 1; j <= n; j++)
for (i = j; i <= n; i++)
A(i, j) = nag_complex(0.0, 0.0);
}
else if (fail.code != NE_NOERROR) {
printf("Error from nag_zpstrf (f07krc)\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* Print rank of A. */
printf("\nComputed rank: %" NAG_IFMT "\n\n", rank);
/* Print factorization using
* nag_gen_complx_mat_print_comp (x04dbc).
* Print complex general matrix (comprehensive)
*/
fflush(stdout);
nag_gen_complx_mat_print_comp(order, matrix, Nag_NonUnitDiag, n, n,
a, n, Nag_BracketForm, "%5.2f", "Factor",
Nag_IntegerLabels, NULL, Nag_IntegerLabels,
NULL, 80, 0, 0, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
/* Print pivot indices. */
printf("\nPivots:\n");
for (i = 0; i < n; i++)
printf("%11" NAG_IFMT "", piv[i]);
printf("\n");
END:
NAG_FREE(a);
NAG_FREE(piv);
return exit_status;
}