redhat man page for cpttrs

CPTTRS(l)								 )								 CPTTRS(l)

NAME
       CPTTRS - solve a tridiagonal system of the form A * X = B using the factorization A = U'*D*U or A = L*D*L' computed by CPTTRF

SYNOPSIS
       SUBROUTINE CPTTRS( UPLO, N, NRHS, D, E, B, LDB, INFO )

	   CHARACTER	  UPLO

	   INTEGER	  INFO, LDB, N, NRHS

	   REAL 	  D( * )

	   COMPLEX	  B( LDB, * ), E( * )

PURPOSE
       CPTTRS solves a tridiagonal system of the form A * X = B using the factorization A = U'*D*U or A = L*D*L' computed by CPTTRF. D is a diago-
       nal matrix specified in the vector D, U (or L) is a unit bidiagonal matrix whose superdiagonal (subdiagonal) is specified in the vector	E,
       and X and B are N by NRHS matrices.

ARGUMENTS
       UPLO    (input) CHARACTER*1
	       Specifies  the form of the factorization and whether the vector E is the superdiagonal of the upper bidiagonal factor U or the sub-
	       diagonal of the lower bidiagonal factor L.  = 'U':  A = U'*D*U, E is the superdiagonal of U
	       = 'L':  A = L*D*L', E is the subdiagonal of L

       N       (input) INTEGER
	       The order of the tridiagonal 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.

       D       (input) REAL array, dimension (N)
	       The n diagonal elements of the diagonal matrix D from the factorization A = U'*D*U or A = L*D*L'.

       E       (input) COMPLEX array, dimension (N-1)
	       If UPLO = 'U', the (n-1) superdiagonal elements of the unit bidiagonal factor U from the factorization A = U'*D*U.  If UPLO =  'L',
	       the (n-1) subdiagonal elements of the unit bidiagonal factor L from the factorization A = L*D*L'.

       B       (input/output) REAL array, dimension (LDB,NRHS)
	       On entry, the right hand side vectors B for the system of linear equations.  On exit, the solution vectors, X.

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

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

LAPACK version 3.0						   15 June 2000 							 CPTTRS(l)