SPOTRI(3)      LAPACK routine of NEC Numeric Library Collection      SPOTRI(3)



NAME
       SPOTRI

SYNOPSIS
       SUBROUTINE SPOTRI (UPLO, N, A, LDA, INFO)



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
            computed by SPOTRF.




ARGUMENTS
           UPLO      (input)
                     UPLO is CHARACTER*1
                     = 'U':  Upper triangle of A is stored;
                     = 'L':  Lower triangle of A is stored.

           N         (input)
                     N is INTEGER
                     The order of the matrix A.  N >= 0.

           A         (input/output)
                     A is 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)
                     LDA is INTEGER
                     The leading dimension of the array A.  LDA >= max(1,N).

           INFO      (output)
                     INFO is 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 routine                  31 October 2017                      SPOTRI(3)