cpbcon - estimate the reciprocal of the condition number (in the 1-norm) of a complex Hermitian positive definite band matrix using the Cholesky factorization A = U**H*U or A = L*L**H computed by CPBTRF
SUBROUTINE CPBCON( UPLO, N, NDIAG, A, LDA, ANORM, RCOND, WORK, * WORK2, INFO) CHARACTER * 1 UPLO COMPLEX A(LDA,*), WORK(*) INTEGER N, NDIAG, LDA, INFO REAL ANORM, RCOND REAL WORK2(*)
SUBROUTINE CPBCON_64( UPLO, N, NDIAG, A, LDA, ANORM, RCOND, WORK, * WORK2, INFO) CHARACTER * 1 UPLO COMPLEX A(LDA,*), WORK(*) INTEGER*8 N, NDIAG, LDA, INFO REAL ANORM, RCOND REAL WORK2(*)
SUBROUTINE PBCON( UPLO, [N], NDIAG, A, [LDA], ANORM, RCOND, [WORK], * [WORK2], [INFO]) CHARACTER(LEN=1) :: UPLO COMPLEX, DIMENSION(:) :: WORK COMPLEX, DIMENSION(:,:) :: A INTEGER :: N, NDIAG, LDA, INFO REAL :: ANORM, RCOND REAL, DIMENSION(:) :: WORK2
SUBROUTINE PBCON_64( UPLO, [N], NDIAG, A, [LDA], ANORM, RCOND, [WORK], * [WORK2], [INFO]) CHARACTER(LEN=1) :: UPLO COMPLEX, DIMENSION(:) :: WORK COMPLEX, DIMENSION(:,:) :: A INTEGER(8) :: N, NDIAG, LDA, INFO REAL :: ANORM, RCOND REAL, DIMENSION(:) :: WORK2
#include <sunperf.h>
void cpbcon(char uplo, int n, int ndiag, complex *a, int lda, float anorm, float *rcond, int *info);
void cpbcon_64(char uplo, long n, long ndiag, complex *a, long lda, float anorm, float *rcond, long *info);
cpbcon estimates the reciprocal of the condition number (in the 1-norm) of a complex Hermitian positive definite band matrix using the Cholesky factorization A = U**H*U or A = L*L**H computed by CPBTRF.
An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
= 'U': Upper triangular factor stored in A;
= 'L': Lower triangular factor stored in A.
A(kd+1+i-j,j)
= U(i,j)
for max(1,j-kd)
< =i < =j;
if UPLO ='L', A(1+i-j,j)
= L(i,j)
for j < =i < =min(n,j+kd).
inv(A)
computed in this routine.
dimension(2*N)
dimension(N)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value