chptri(3P) Sun Performance Library chptri(3P)NAMEchptri - compute the inverse of a complex Hermitian indefinite matrix A
in packed storage using the factorization A = U*D*U**H or A = L*D*L**H
computed by CHPTRF
SYNOPSIS
SUBROUTINE CHPTRI(UPLO, N, A, IPIVOT, WORK, INFO)
CHARACTER * 1 UPLO
COMPLEX A(*), WORK(*)
INTEGER N, INFO
INTEGER IPIVOT(*)
SUBROUTINE CHPTRI_64(UPLO, N, A, IPIVOT, WORK, INFO)
CHARACTER * 1 UPLO
COMPLEX A(*), WORK(*)
INTEGER*8 N, INFO
INTEGER*8 IPIVOT(*)
F95 INTERFACE
SUBROUTINE HPTRI(UPLO, [N], A, IPIVOT, [WORK], [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: A, WORK
INTEGER :: N, INFO
INTEGER, DIMENSION(:) :: IPIVOT
SUBROUTINE HPTRI_64(UPLO, [N], A, IPIVOT, [WORK], [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: A, WORK
INTEGER(8) :: N, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT
C INTERFACE
#include <sunperf.h>
void chptri(char uplo, int n, complex *a, int *ipivot, int *info);
void chptri_64(char uplo, long n, complex *a, long *ipivot, long
*info);
PURPOSEchptri computes the inverse of a complex Hermitian indefinite matrix A
in packed storage using the factorization A = U*D*U**H or A = L*D*L**H
computed by CHPTRF.
ARGUMENTS
UPLO (input)
Specifies whether the details of the factorization are stored
as an upper or lower triangular matrix. = 'U': Upper trian‐
gular, form is A = U*D*U**H;
= 'L': Lower triangular, form is A = L*D*L**H.
N (input) The order of the matrix A. N >= 0.
A (input/output) COMPLEX array, dimension (N*(N+1)/2)
On entry, the block diagonal matrix D and the multipliers
used to obtain the factor U or L as computed by CHPTRF,
stored as a packed triangular matrix.
On exit, if INFO = 0, the (Hermitian) inverse of the original
matrix, stored as a packed triangular matrix. The j-th column
of inv(A) is stored in the array A as follows: if UPLO = 'U',
A(i + (j-1)*j/2) = inv(A)(i,j) for 1<=i<=j; if UPLO = 'L',
A(i + (j-1)*(2n-j)/2) = inv(A)(i,j) for j<=i<=n.
IPIVOT (input) INTEGER array, dimension (N)
Details of the interchanges and the block structure of D as
determined by CHPTRF.
WORK (workspace)
COMPLEX array, dimension(N)
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, D(i,i) = 0; the matrix is singular and its
inverse could not be computed.
6 Mar 2009 chptri(3P)
