dlagtm.f (3)  Linux Manuals
NAME
dlagtm.f 
SYNOPSIS
Functions/Subroutines
subroutine dlagtm (TRANS, N, NRHS, ALPHA, DL, D, DU, X, LDX, BETA, B, LDB)
DLAGTM performs a matrixmatrix 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 matrixmatrix 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 matrixvector 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
NN is INTEGER The order of the matrix A. N >= 0.
NRHSNRHS is INTEGER The number of right hand sides, i.e., the number of columns of the matrices X and B.
ALPHAALPHA is DOUBLE PRECISION The scalar alpha. ALPHA must be 0., 1., or 1.; otherwise, it is assumed to be 0.
DLDL is DOUBLE PRECISION array, dimension (N1) The (n1) subdiagonal elements of T.
DD is DOUBLE PRECISION array, dimension (N) The diagonal elements of T.
DUDU is DOUBLE PRECISION array, dimension (N1) The (n1) superdiagonal elements of T.
XX is DOUBLE PRECISION array, dimension (LDX,NRHS) The N by NRHS matrix X.
LDXLDX is INTEGER The leading dimension of the array X. LDX >= max(N,1).
BETABETA is DOUBLE PRECISION The scalar beta. BETA must be 0., 1., or 1.; otherwise, it is assumed to be 1.
BB 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.
LDBLDB 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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