dlagtm.f man page

dlagtm.f —

Synopsis

Functions/Subroutines

subroutine dlagtm (TRANS, N, NRHS, ALPHA, DL, D, DU, X, LDX, BETA, B, LDB)
DLAGTM performs a matrix-matrix product of the form C = αAB+βC, where A is a tridiagonal matrix, B and C are rectangular matrices, and α and β are scalars, which may be 0, 1, or -1.

Function/Subroutine Documentation

subroutine dlagtm (characterTRANS, integerN, integerNRHS, double precisionALPHA, double precision, dimension( * )DL, double precision, dimension( * )D, double precision, dimension( * )DU, double precision, dimension( ldx, * )X, integerLDX, double precisionBETA, double precision, dimension( ldb, * )B, integerLDB)

DLAGTM performs a matrix-matrix product of the form C = αAB+βC, where A is a tridiagonal matrix, B and C are rectangular matrices, and α and β are scalars, which may be 0, 1, or -1.

Purpose:

DLAGTM performs a matrix-vector product of the form

   B := alpha * A * X + beta * B

where A is a tridiagonal matrix of order N, B and X are N by NRHS
matrices, and alpha and beta are real scalars, each of which may be
0., 1., or -1.

Parameters:

TRANS

TRANS is CHARACTER*1
Specifies the operation applied to A.
= 'N':  No transpose, B := alpha * A * X + beta * B
= 'T':  Transpose,    B := alpha * A'* X + beta * B
= 'C':  Conjugate transpose = Transpose

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 matrices X and B.

ALPHA

ALPHA is DOUBLE PRECISION
The scalar alpha.  ALPHA must be 0., 1., or -1.; otherwise,
it is assumed to be 0.

DL

DL is DOUBLE PRECISION array, dimension (N-1)
The (n-1) sub-diagonal elements of T.

D

D is DOUBLE PRECISION array, dimension (N)
The diagonal elements of T.

DU

DU is DOUBLE PRECISION array, dimension (N-1)
The (n-1) super-diagonal elements of T.

X

X is DOUBLE PRECISION array, dimension (LDX,NRHS)
The N by NRHS matrix X.

LDX

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

BETA

BETA is DOUBLE PRECISION
The scalar beta.  BETA must be 0., 1., or -1.; otherwise,
it is assumed to be 1.

B

B is DOUBLE PRECISION array, dimension (LDB,NRHS)
On entry, the N by NRHS matrix B.
On exit, B is overwritten by the matrix expression
B := alpha * A * X + beta * B.

LDB

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

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 145 of file dlagtm.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK