zpptrs(3)

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 computed by ZPP

TRF

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 computed by ZPP

TRF.

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 j-th column of U or L is stored in the array

AP as follows: if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for

1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2n-j)/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 i-th argument had an ille

gal value

LAPACK version 3.0 15 June 2000

ZPPTRS(3)