• NAME
• SYNOPSIS
• F95 INTERFACE
• C INTERFACE
• PURPOSE
• ARGUMENTS

NAME

dpotri - compute the inverse of a real symmetric positive definite matrix A using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF

SYNOPSIS

  SUBROUTINE DPOTRI( UPLO, N, A, LDA, INFO)
  CHARACTER * 1 UPLO
  INTEGER N, LDA, INFO
  DOUBLE PRECISION A(LDA,*)

  SUBROUTINE DPOTRI_64( UPLO, N, A, LDA, INFO)
  CHARACTER * 1 UPLO
  INTEGER*8 N, LDA, INFO
  DOUBLE PRECISION A(LDA,*)

F95 INTERFACE

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

  SUBROUTINE POTRI_64( UPLO, [N], A, [LDA], [INFO])
  CHARACTER(LEN=1) :: UPLO
  INTEGER(8) :: N, LDA, INFO
  REAL(8), DIMENSION(:,:) :: A

C INTERFACE

#include <sunperf.h>

void dpotri(char uplo, int n, double *a, int lda, int *info);

void dpotri_64(char uplo, long n, double *a, long lda, long *info);

PURPOSE

dpotri computes the inverse of a real symmetric positive definite matrix A using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF.

ARGUMENTS

• UPLO (input)
  

   = 'U':  Upper triangle of A is stored;

   = 'L':  Lower triangle of A is stored.

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

• A (input/output)
  On entry, the triangular factor U or L from the Cholesky factorization A = U**T*U or A = L*L**T, as computed by SPOTRF. On exit, the upper or lower triangle of the (symmetric) inverse of A, overwriting the input factor U or L.

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

• INFO (output)
  

   = 0:  successful exit

   < 0:  if INFO  = -i, the i-th argument had an illegal value

   > 0:  if INFO  = i, the (i,i) element of the factor U or L is
  zero, and the inverse could not be computed.