dgtsv.f man page

dgtsv.f —

Synopsis

Functions/Subroutines

subroutine dgtsv (N, NRHS, DL, D, DU, B, LDB, INFO)
DGTSV computes the solution to system of linear equations A * X = B for GT matrices

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 computes the solution to system of linear equations A * X = B for GT matrices

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:

September 2012

Definition at line 128 of file dgtsv.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dgtsv(3) is an alias of dgtsv.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK