
ZPPTRS(l) ) ZPPTRS(l)
NAME
ZPPTRS  solve a system of linear equations A*X = B with a Hermitian positive definite
matrix A in packed storage using the Cholesky factorization A = U**H*U or A = L*L**H com
puted by ZPPTRF
SYNOPSIS
SUBROUTINE ZPPTRS( UPLO, N, NRHS, AP, B, LDB, INFO )
CHARACTER UPLO
INTEGER INFO, LDB, N, NRHS
COMPLEX*16 AP( * ), B( LDB, * )
PURPOSE
ZPPTRS solves a system of linear equations A*X = B with a Hermitian positive definite
matrix A in packed storage using the Cholesky factorization A = U**H*U or A = L*L**H com
puted by ZPPTRF.
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.
AP (input) COMPLEX*16 array, dimension (N*(N+1)/2)
The triangular factor U or L from the Cholesky factorization A = U**H*U or A =
L*L**H, packed columnwise in a linear array. The jth column of U or L is stored
in the array AP as follows: if UPLO = 'U', AP(i + (j1)*j/2) = U(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j1)*(2nj)/2) = L(i,j) for j<=i<=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 ith argument had an illegal value
LAPACK version 3.0 15 June 2000 ZPPTRS(l) 
