ssytri

NAME

ssytri - compute the inverse of a real symmetric indefinite matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by SSYTRF

SYNOPSIS 

  SUBROUTINE SSYTRI( UPLO, N, A, LDA, IPIVOT, WORK, INFO)
  CHARACTER * 1 UPLO
  INTEGER N, LDA, INFO
  INTEGER IPIVOT(*)
  REAL A(LDA,*), WORK(*)
 
  SUBROUTINE SSYTRI_64( UPLO, N, A, LDA, IPIVOT, WORK, INFO)
  CHARACTER * 1 UPLO
  INTEGER*8 N, LDA, INFO
  INTEGER*8 IPIVOT(*)
  REAL A(LDA,*), WORK(*)

F95 INTERFACE 

  SUBROUTINE SYTRI( UPLO, N, A, [LDA], IPIVOT, [WORK], [INFO])
  CHARACTER(LEN=1) :: UPLO
  INTEGER :: N, LDA, INFO
  INTEGER, DIMENSION(:) :: IPIVOT
  REAL, DIMENSION(:) :: WORK
  REAL, DIMENSION(:,:) :: A
 
  SUBROUTINE SYTRI_64( UPLO, N, A, [LDA], IPIVOT, [WORK], [INFO])
  CHARACTER(LEN=1) :: UPLO
  INTEGER(8) :: N, LDA, INFO
  INTEGER(8), DIMENSION(:) :: IPIVOT
  REAL, DIMENSION(:) :: WORK
  REAL, DIMENSION(:,:) :: A

C INTERFACE

#include <sunperf.h>

void ssytri(char uplo, int n, float *a, int lda, int *ipivot, int *info);

void ssytri_64(char uplo, long n, float *a, long lda, long *ipivot, long *info);

PURPOSE

ssytri computes the inverse of a real symmetric indefinite matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by SSYTRF.

ARGUMENTS

* UPLO (input)
Specifies whether the details of the factorization are stored as an upper or lower triangular matrix.

* N (input)
The order of the matrix A. N >= 0.

* A (input/output)
On entry, the block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by SSYTRF.

On exit, if INFO = 0, the (symmetric) inverse of the original matrix. If UPLO = 'U', the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced; if UPLO = 'L' the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced.

* LDA (input)
The leading dimension of the array A. LDA >= max(1,N).

* IPIVOT (input)
Details of the interchanges and the block structure of D as determined by SSYTRF.

* WORK (workspace)
dimension(N)

* INFO (output)