CXML
        	    
LAPACK version 3.0
zhpgst(3)

PURPOSE
  ZHPGST - reduce a complex Hermitian-definite generalized eigenproblem to
  standard form, using packed storage

SYNTAX
  SUBROUTINE ZHPGST( ITYPE, UPLO, N, AP, BP, INFO )

      CHARACTER	     UPLO

      INTEGER	     INFO, ITYPE, N

      COMPLEX*16     AP( * ), BP( * )

DESCRIPTION
  ZHPGST reduces a complex Hermitian-definite generalized eigenproblem to
  standard form, using packed storage.	If ITYPE = 1, the problem is A*x =
  lambda*B*x,
  and A is overwritten by inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H)

  If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or
  B*A*x = lambda*x, and A is overwritten by U*A*U**H or L**H*A*L.

  B must have been previously factorized as U**H*U or L*L**H by ZPPTRF.

ARGUMENTS
  ITYPE	  (input) INTEGER
	  = 1: compute inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H);
	  = 2 or 3: compute U*A*U**H or L**H*A*L.

  UPLO	  (input) CHARACTER
	  = 'U':  Upper triangle of A is stored and B is factored as U**H*U;
	  = 'L':  Lower triangle of A is stored and B is factored as L*L**H.

  N	  (input) INTEGER
	  The order of the matrices A and B.  N >= 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.

	  On exit, if INFO = 0, the transformed matrix, stored in the same
	  format as A.

  BP	  (input) COMPLEX*16 array, dimension (N*(N+1)/2)
	  The triangular factor from the Cholesky factorization of B, stored
	  in the same format as A, as returned by ZPPTRF.

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