dpotri(3)

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 ille

gal 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 3.0 15 June 2000

DPOTRI(3)