ZTRTRS(l)		LAPACK routine (version	1.1)		    ZTRTRS(l)

NAME
  ZTRTRS - solve a triangular system of	the form   A * X = B, A**T * X = B,
  or A**H * X =	B,

SYNOPSIS

  SUBROUTINE ZTRTRS( UPLO, TRANS, DIAG,	N, NRHS, A, LDA, B, LDB, INFO )

      CHARACTER	     DIAG, TRANS, UPLO

      INTEGER	     INFO, LDA,	LDB, N,	NRHS

      COMPLEX*16     A(	LDA, * ), B( LDB, * )

PURPOSE
  ZTRTRS solves	a triangular system of the form

  where	A is a triangular matrix of order N, and B is an N-by-NRHS matrix.  A
  check	is made	to verify that A is nonsingular.

ARGUMENTS

  UPLO	  (input) CHARACTER*1
	  = 'U':  A is upper triangular;
	  = 'L':  A is lower triangular.

  TRANS	  (input) CHARACTER*1
	  Specifies the	form of	the system of equations:
	  = 'N':  A * X	= B	(No transpose)
	  = 'T':  A**T * X = B	(Transpose)
	  = 'C':  A**H * X = B	(Conjugate transpose)

  DIAG	  (input) CHARACTER*1
	  = 'N':  A is non-unit	triangular;
	  = 'U':  A is unit triangular.

  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.

  A	  (input) COMPLEX*16 array, dimension (LDA,N)
	  The triangular matrix	A.  If UPLO = 'U', the leading N-by-N upper
	  triangular part of the array A contains the upper triangular
	  matrix, and the strictly lower triangular part of A is not refer-
	  enced.  If UPLO = 'L', the leading N-by-N lower triangular part of
	  the array A contains the lower triangular matrix, and	the strictly
	  upper	triangular part	of A is	not referenced.	 If DIAG = 'U',	the
	  diagonal elements of A are also not referenced and are assumed to
	  be 1.

  LDA	  (input) INTEGER
	  The leading dimension	of the array A.	 LDA >=	max(1,N).

  B	  (input/output) COMPLEX*16 array, dimension (LDB,NRHS)
	  On entry, the	right hand side	matrix B.  On exit, if INFO = 0, 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
	  > 0: if INFO = i, the	i-th diagonal element of A is zero, indicat-
	  ing that the matrix is singular and the solutions X have not been
	  computed.