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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 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 computed by ZPPTRF. ARGUMENTS UPLO (input) CHARACTER*1 Specifies whether the factor stored in A is upper or lower triangular. = '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 fac- torization A = U**H*U or A = L*L**H, packed column- wise 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 illegal value