p?potri

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 12/16/2022

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p?potri

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

Syntax

call pspotri(uplo, n, a, ia, ja, desca, info)

call pdpotri(uplo, n, a, ia, ja, desca, info)

call pcpotri(uplo, n, a, ia, ja, desca, info)

call pzpotri(uplo, n, a, ia, ja, desca, info)

Include Files

Description

The p?potriroutine 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) = U^H*U or sub(A) = L*L^H computed by p?potrf.

Input Parameters

uplo

(global) CHARACTER*1. 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) INTEGER. The number of rows and columns to be operated on, that is, the order of the distributed matrix sub(A) (n≥0).

a

(local)

REAL for pspotri

DOUBLE PRECISION for pdpotri

COMPLEX for pcpotri

DOUBLE COMPLEX for pzpotri.

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) = U^H*U, or sub(A) = L*L^H, as computed by p?potrf.

ia, ja

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

info < 0:

If the i-th argument is an array and the j-th entry 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.

Parent topic: Matrix Inversion: ScaLAPACK Computational Routines

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