dgtsv(l) [redhat man page]

DGTSV(l)								 )								  DGTSV(l)

NAME

       DGTSV - solve the equation  A*X = B,

SYNOPSIS

       SUBROUTINE DGTSV( N, NRHS, DL, D, DU, B, LDB, INFO )

	   INTEGER	 INFO, LDB, N, NRHS

	   DOUBLE	 PRECISION B( LDB, * ), D( * ), DL( * ), DU( * )

PURPOSE

       DGTSV solves the equation A*X = B, where A is an n by n tridiagonal matrix, by Gaussian elimination with partial pivoting.

       Note that the equation  A'*X = B  may be solved by interchanging the order of the arguments DU and DL.

ARGUMENTS

       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.

       DL      (input/output) DOUBLE PRECISION array, dimension (N-1)
	       On entry, DL must contain the (n-1) sub-diagonal elements of A.

	       On  exit, DL is overwritten by the (n-2) elements of the second super-diagonal of the upper triangular matrix U from the LU factor-
	       ization of A, in DL(1), ..., DL(n-2).

       D       (input/output) DOUBLE PRECISION array, dimension (N)
	       On entry, D must contain the diagonal elements of A.

	       On exit, D is overwritten by the n diagonal elements of U.

       DU      (input/output) DOUBLE PRECISION array, dimension (N-1)
	       On entry, DU must contain the (n-1) super-diagonal elements of A.

	       On exit, DU is overwritten by the (n-1) elements of the first super-diagonal of U.

       B       (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
	       On entry, the N by NRHS matrix of 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, U(i,i) is exactly zero, and the solution has not been computed.  The factorization has not been completed  unless
	       i = N.

LAPACK version 3.0						   15 June 2000 							  DGTSV(l)

dgtsv.f(3)							      LAPACK								dgtsv.f(3)

NAME

       dgtsv.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dgtsv (N, NRHS, DL, D, DU, B, LDB, INFO)
	   DGTSV

Function/Subroutine Documentation
   subroutine dgtsv (integerN, integerNRHS, double precision, dimension( * )DL, double precision, dimension( * )D, double precision, dimension( *
       )DU, double precision, dimension( ldb, * )B, integerLDB, integerINFO)
       DGTSV

       Purpose:

	    DGTSV  solves the equation

	       A*X = B,

	    where A is an n by n tridiagonal matrix, by Gaussian elimination with
	    partial pivoting.

	    Note that the equation  A**T*X = B	may be solved by interchanging the
	    order of the arguments DU and DL.

       Parameters:
	   N

		     N is INTEGER
		     The order of the matrix A.  N >= 0.

	   NRHS

		     NRHS is INTEGER
		     The number of right hand sides, i.e., the number of columns
		     of the matrix B.  NRHS >= 0.

	   DL

		     DL is DOUBLE PRECISION array, dimension (N-1)
		     On entry, DL must contain the (n-1) sub-diagonal elements of
		     A.

		     On exit, DL is overwritten by the (n-2) elements of the
		     second super-diagonal of the upper triangular matrix U from
		     the LU factorization of A, in DL(1), ..., DL(n-2).

	   D

		     D is DOUBLE PRECISION array, dimension (N)
		     On entry, D must contain the diagonal elements of A.

		     On exit, D is overwritten by the n diagonal elements of U.

	   DU

		     DU is DOUBLE PRECISION array, dimension (N-1)
		     On entry, DU must contain the (n-1) super-diagonal elements
		     of A.

		     On exit, DU is overwritten by the (n-1) elements of the first
		     super-diagonal of U.

	   B

		     B is DOUBLE PRECISION array, dimension (LDB,NRHS)
		     On entry, the N by NRHS matrix of right hand side matrix B.
		     On exit, if INFO = 0, the N by NRHS solution matrix X.

	   LDB

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

	   INFO

		     INFO is INTEGER
		     = 0: successful exit
		     < 0: if INFO = -i, the i-th argument had an illegal value
		     > 0: if INFO = i, U(i,i) is exactly zero, and the solution
			  has not been computed.  The factorization has not been
			  completed unless i = N.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 128 of file dgtsv.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.1							  Sun May 26 2013							dgtsv.f(3)