.TH SLAGTM 1 "November 2006" " LAPACK auxiliary routine (version 3.1) " " LAPACK auxiliary routine (version 3.1) " .SH NAME SLAGTM - 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 .SH SYNOPSIS .TP 19 SUBROUTINE SLAGTM( TRANS, N, NRHS, ALPHA, DL, D, DU, X, LDX, BETA, B, LDB ) .TP 19 .ti +4 CHARACTER TRANS .TP 19 .ti +4 INTEGER LDB, LDX, N, NRHS .TP 19 .ti +4 REAL ALPHA, BETA .TP 19 .ti +4 REAL B( LDB, * ), D( * ), DL( * ), DU( * ), X( LDX, * ) .SH PURPOSE SLAGTM performs a matrix-vector product of the form .SH ARGUMENTS .TP 8 TRANS (input) CHARACTER*1 Specifies the operation applied to A. = \(aqN\(aq: No transpose, B := alpha * A * X + beta * B .br = \(aqT\(aq: Transpose, B := alpha * A\(aq* X + beta * B .br = \(aqC\(aq: Conjugate transpose = Transpose .TP 8 N (input) INTEGER The order of the matrix A. N >= 0. .TP 8 NRHS (input) INTEGER The number of right hand sides, i.e., the number of columns of the matrices X and B. .TP 8 ALPHA (input) REAL The scalar alpha. ALPHA must be 0., 1., or -1.; otherwise, it is assumed to be 0. .TP 8 DL (input) REAL array, dimension (N-1) The (n-1) sub-diagonal elements of T. .TP 8 D (input) REAL array, dimension (N) The diagonal elements of T. .TP 8 DU (input) REAL array, dimension (N-1) The (n-1) super-diagonal elements of T. .TP 8 X (input) REAL array, dimension (LDX,NRHS) The N by NRHS matrix X. LDX (input) INTEGER The leading dimension of the array X. LDX >= max(N,1). .TP 8 BETA (input) REAL The scalar beta. BETA must be 0., 1., or -1.; otherwise, it is assumed to be 1. .TP 8 B (input/output) REAL 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. .TP 8 LDB (input) INTEGER The leading dimension of the array B. LDB >= max(N,1).