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RedHat 9 (Linux i386) - man page for spotri (redhat section l)

SPOTRI(l)								 )								 SPOTRI(l)

NAME
SPOTRI - 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 SPOTRF
SYNOPSIS
SUBROUTINE SPOTRI( UPLO, N, A, LDA, INFO ) CHARACTER UPLO INTEGER INFO, LDA, N REAL A( LDA, * )
PURPOSE
SPOTRI 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 SPOTRF.
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) REAL 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 SPOTRF. 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 SPOTRI(l)