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 DPOTRF

SYNOPSIS

SUBROUTINE DPOTRI(
UPLO, N, A, LDA, INFO )

CHARACTER UPLO

INTEGER INFO, LDA, N

DOUBLE PRECISION A( LDA, ∗ )

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 DPOTRF. 
 

ARGUMENTS

UPLO    (input) CHARACTER∗1
= ’U’:  Upper triangle of A is stored;
= ’L’:  Lower triangle of A is stored.

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

A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
On entry, the triangular factor U or L from the Cholesky factorization A = U∗∗T∗U or A = L∗L∗∗T, as computed by DPOTRF. On exit, the upper or lower triangle of the (symmetric) inverse of A, overwriting the input factor U or L.

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

INFO    (output) INTEGER
= 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.

  —  LAPACK version 2.0  —  08 October 1994