f08ctce.c

/* nag_lapackeig_zungql (f08ctc) Example Program.
 *
 * Copyright 2025 Numerical Algorithms Group.
 *
 * Mark 31.1, 2025.
 */
#include<nag.h>
#include<stdio.h>
intmain(void){
/* Scalars */
Integeri,j,m,n,pda;
Integerexit_status=0;
/* Arrays */
char*title=0;
Complex*a=0,*tau=0;
/* Nag Types */
Nag_OrderTypeorder;
NagErrorfail;
#ifdef NAG_COLUMN_MAJOR
#define A(I, J) a[(J - 1) * pda + I - 1]
order=Nag_ColMajor;
#else
#define A(I, J) a[(I - 1) * pda + J - 1]
order=Nag_RowMajor;
#endif
INIT_FAIL(fail);
printf("nag_lapackeig_zungql (f08ctc) Example Program Results\n\n");
/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%"NAG_IFMT"%"NAG_IFMT"%*[^\n]",&m,&n);
#ifdef NAG_COLUMN_MAJOR
pda=m;
#else
pda=n;
#endif
/* Allocate memory */
if(!(title=NAG_ALLOC(31,char))||!(a=NAG_ALLOC(m*n,Complex))||
!(tau=NAG_ALLOC(n,Complex))){
printf("Allocation failure\n");
exit_status=-1;
gotoEND;
}
/* Read A from data file */
for(i=1;i<=m;++i)
for(j=1;j<=n;++j)
scanf(" ( %lf , %lf )",&A(i,j).re,&A(i,j).im);
scanf("%*[^\n]");
/* nag_lapackeig_zgeqlf (f08csc).
 * Compute the QL factorization of A.
 */
nag_lapackeig_zgeqlf(order,m,n,a,pda,tau,&fail);
if(fail.code!=NE_NOERROR){
printf("Error from nag_lapackeig_zgeqlf (f08csc).\n%s\n",fail.message);
exit_status=1;
gotoEND;
}
/* nag_lapackeig_zungql (f08ctc).
 * Form the leading n columns of Q explicitly.
 */
nag_lapackeig_zungql(order,m,n,n,a,pda,tau,&fail);
if(fail.code!=NE_NOERROR){
printf("Error from nag_lapackeig_zungql (f08ctc).\n%s\n",fail.message);
exit_status=1;
gotoEND;
}
sprintf(title,"The leading %4"NAG_IFMT" columns of Q",n);
/* nag_file_print_matrix_complex_gen_comp (x04dbc).
 * Print the leading n columns of Q.
 */
fflush(stdout);
nag_file_print_matrix_complex_gen_comp(
order,Nag_GeneralMatrix,Nag_NonUnitDiag,m,n,a,pda,Nag_BracketForm,
"%7.4f",title,Nag_IntegerLabels,0,Nag_IntegerLabels,0,80,0,0,
&fail);
if(fail.code!=NE_NOERROR){
printf("Error from nag_file_print_matrix_complex_gen_comp (x04dbc).\n%s\n",
fail.message);
exit_status=1;
}
END:
NAG_FREE(title);
NAG_FREE(a);
NAG_FREE(tau);
returnexit_status;
}
#undef A