DLAGTM (3) Linux Manual 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

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