clagtm-f(3)

clagtm.f –

Synopsis

Functions/Subroutines

subroutine clagtm (TRANS, N, NRHS, ALPHA, DL, D, DU, X, LDX, BETA, B, LDB)
CLAGTM 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 clagtm (characterTRANS, integerN, integerNRHS, realALPHA, complex, dimension( * )DL, complex, dimension( * )D, complex, dimension( * )DU, complex, dimension( ldx, * )X, integerLDX, realBETA, complex, dimension( ldb, * )B, integerLDB)

CLAGTM 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:

 CLAGTM 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**T * X + beta * B
 = 'C': Conjugate transpose, B := alpha * A**H * X + beta * B

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

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

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

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

 X is COMPLEX 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 REAL
 The scalar beta. BETA must be 0., 1., or -1.; otherwise,
 it is assumed to be 1.

 B is COMPLEX 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 clagtm.f.

Author

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