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# zpotri

```
NAME
ZPOTRI - compute the inverse of a complex Hermitian positive
definite matrix A using the Cholesky factorization A =
U**H*U or A = L*L**H computed by ZPOTRF

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

CHARACTER      UPLO

INTEGER        INFO, LDA, N

COMPLEX*16     A( LDA, * )

PURPOSE
ZPOTRI computes the inverse of a complex Hermitian positive
definite matrix A using the Cholesky factorization A =
U**H*U or A = L*L**H computed by ZPOTRF.

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) COMPLEX*16 array, dimension (LDA,N)
On entry, the triangular factor U or L from the
Cholesky factorization A = U**H*U or A = L*L**H, as
computed by ZPOTRF.  On exit, the upper or lower
triangle of the (Hermitian) inverse of A, overwrit-
ing 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.
```