sgtsv.f man page

sgtsv.f —

Synopsis

Functions/Subroutines

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

Function/Subroutine Documentation

subroutine sgtsv (integerN, integerNRHS, real, dimension( * )DL, real, dimension( * )D, real, dimension( * )DU, real, dimension( ldb, * )B, integerLDB, integerINFO)

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

Purpose:

SGTSV  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 REAL 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 REAL 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 REAL 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 REAL 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 sgtsv.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK