Computes the inverse of a symmetric/Hermitian positive definite distributed matrix.

## Syntax

void pspotri (char *uplo , MKL_INT *n , float *a , MKL_INT *ia , MKL_INT *ja , MKL_INT *desca , MKL_INT *info );

void pdpotri (char *uplo , MKL_INT *n , double *a , MKL_INT *ia , MKL_INT *ja , MKL_INT *desca , MKL_INT *info );

void pcpotri (char *uplo , MKL_INT *n , MKL_Complex8 *a , MKL_INT *ia , MKL_INT *ja , MKL_INT *desca , MKL_INT *info );

void pzpotri (char *uplo , MKL_INT *n , MKL_Complex16 *a , MKL_INT *ia , MKL_INT *ja , MKL_INT *desca , MKL_INT *info );

## Include Files

• mkl_scalapack.h

## Description

The p?potrifunction computes the inverse of a real symmetric or complex Hermitian positive definite distributed matrix sub(A) = A(ia:ia+n-1, ja:ja+n-1) using the Cholesky factorization sub(A) = UH*U or sub(A) = L*LH computed by p?potrf.

## Input Parameters

uplo

(global) Must be 'U' or 'L'.

Specifies whether the upper or lower triangular part of the symmetric/Hermitian matrix sub(A) is stored.

If uplo = 'U', upper triangle of sub(A) is stored. If uplo = 'L', lower triangle of sub(A) is stored.

n

(global) The number of rows and columns to be operated on, that is, the order of the distributed matrix sub(A) (n0).

a

(local)

Pointer into the local memory to an array of local size lld_a*LOCc(ja+n-1).

On entry, the array a contains the local pieces of the triangular factor U or L from the Cholesky factorization sub(A) = UH*U, or sub(A) = L*LH, as computed by p?potrf.

ia, ja

(global) The row and column indices in the global matrix A indicating the first row and the first column of the matrix sub(A), respectively.

desca

(global and local) array of size dlen_. The array descriptor for the distributed matrix A.

## Output Parameters

a

On exit, overwritten by the local pieces of the upper or lower triangle of the (symmetric/Hermitian) inverse of sub(A).

info

(global) If info=0, the execution is successful.

info < 0:

If the i-th argument is an array and the j-th entry, indexed j - 1, had an illegal value, then info = -(i*100+j); if the i-th argument is a scalar and had an illegal value, then info = -i.

info> 0:

If info = i, the element (i, i) of the factor U or L is zero, and the inverse could not be computed.