ZPPSV(l)	     LAPACK driver routine (version 1.1)	     ZPPSV(l)

NAME
  ZPPSV	- compute the solution to a complex system of linear equations	A * X
  = B,

SYNOPSIS

  SUBROUTINE ZPPSV( UPLO, N, NRHS, AP, B, LDB, INFO )

      CHARACTER	    UPLO

      INTEGER	    INFO, LDB, N, NRHS

      COMPLEX*16    AP(	* ), B(	LDB, * )

PURPOSE
  ZPPSV	computes the solution to a complex system of linear equations
     A * X = B,	where A	is an N-by-N Hermitian positive	definite matrix
  stored in packed format and X	and B are N-by-NRHS matrices.

  The Cholesky decomposition is	used to	factor A as
     A = U**H* U,  if UPLO = 'U', or
     A = L * L**H,  if UPLO = 'L',
  where	U is an	upper triangular matrix	and L is a lower triangular matrix.
  The factored form of A is then used to solve the system of equations A * X
  = B.

ARGUMENTS

  UPLO	  (input) CHARACTER*1
	  = 'U':  Upper	triangle of A is stored;
	  = 'L':  Lower	triangle of A is stored.

  N	  (input) INTEGER
	  The number of	linear equations, i.e.,	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/output) COMPLEX*16 array, dimension (N*(N+1)/2)
	  On entry, the	upper or lower triangle	of the Hermitian matrix	A,
	  packed columnwise in a linear	array.	The j-th column	of A is
	  stored in the	array AP as follows: if	UPLO = 'U', AP(i + (j-1)*j/2)
	  = A(i,j) for 1<=i<=j;	if UPLO	= 'L', AP(i + (j-1)*(2n-j)/2) =
	  A(i,j) for j<=i<=n.  See below for further details.

	  On exit, if INFO = 0,	the factor U or	L from the Cholesky factori-
	  zation A = U**H*U or A = L*L**H, in the same storage format as A.

  B	  (input/output) COMPLEX*16 array, dimension (LDB,NRHS)
	  On entry, the	N-by-NRHS right	hand side matrix B.  On	exit, if INFO
	  = 0, the N-by-NRHS 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
	  > 0:	if INFO	= i, the leading minor of order	i of A is not posi-
	  tive definite, so the	factorization could not	be completed, and the
	  solution has not been	computed.

FURTHER	DETAILS
  The packed storage scheme is illustrated by the following example when N =
  4, UPLO = 'U':

  Two-dimensional storage of the Hermitian matrix A:

     a11 a12 a13 a14
	 a22 a23 a24
	     a33 a34	 (aij =	conjg(aji))
		 a44

  Packed storage of the	upper triangle of A:

  AP = [ a11, a12, a22,	a13, a23, a33, a14, a24, a34, a44 ]