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# zpotrs

```
NAME
ZPOTRS - solve a system of linear equations A*X = B with a
Hermitian positive definite matrix A using the Cholesky fac-
torization A = U**H*U or A = L*L**H computed by ZPOTRF

SYNOPSIS
SUBROUTINE ZPOTRS( UPLO, N, NRHS, A, LDA, B, LDB, INFO )

CHARACTER      UPLO

INTEGER        INFO, LDA, LDB, N, NRHS

COMPLEX*16     A( LDA, * ), B( LDB, * )

PURPOSE
ZPOTRS solves a system of linear equations A*X = B with a
Hermitian positive definite matrix A using the Cholesky fac-
torization 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.

NRHS    (input) INTEGER
The number of right hand sides, i.e., the number of
columns of the matrix B.  NRHS >= 0.

A       (input) COMPLEX*16 array, dimension (LDA,N)
The triangular factor U or L from the Cholesky fac-
torization A = U**H*U or A = L*L**H, as computed by
ZPOTRF.

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

B       (input/output) COMPLEX*16 array, dimension (LDB,NRHS)
On entry, the right hand side matrix B.  On exit,
the solution matrix X.

LDB     (input) INTEGER
The leading dimension of the array B.  LDB >=
max(1,N).

INFO    (output) INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal

value
```