DPOTRI(l) ) DPOTRI(l)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 com‐
puted 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 com‐
puted 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 fac‐
torization 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 3.0 15 June 2000 DPOTRI(l)
