ZLAGTM(3F)ZLAGTM(3F)NAMEZLAGTM - perform 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
SYNOPSIS
SUBROUTINE ZLAGTM( TRANS, N, NRHS, ALPHA, DL, D, DU, X, LDX, BETA, B, LDB
)
CHARACTER TRANS
INTEGER LDB, LDX, N, NRHS
DOUBLE PRECISION ALPHA, BETA
COMPLEX*16 B( LDB, * ), D( * ), DL( * ), DU( * ), X( LDX, * )
PURPOSEZLAGTM performs a matrix-vector product of the form
ARGUMENTS
TRANS (input) CHARACTER
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 (input) INTEGER
The order of the matrix A. N >= 0.
NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns of
the matrices X and B.
ALPHA (input) DOUBLE PRECISION
The scalar alpha. ALPHA must be 0., 1., or -1.; otherwise, it is
assumed to be 0.
DL (input) COMPLEX*16 array, dimension (N-1)
The (n-1) sub-diagonal elements of T.
D (input) COMPLEX*16 array, dimension (N)
The diagonal elements of T.
DU (input) COMPLEX*16 array, dimension (N-1)
The (n-1) super-diagonal elements of T.
X (input) COMPLEX*16 array, dimension (LDX,NRHS)
The N by NRHS matrix X. LDX (input) INTEGER The leading
dimension of the array X. LDX >= max(N,1).
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ZLAGTM(3F)ZLAGTM(3F)
BETA (input) DOUBLE PRECISION
The scalar beta. BETA must be 0., 1., or -1.; otherwise, it is
assumed to be 1.
B (input/output) COMPLEX*16 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 (input) INTEGER
The leading dimension of the array B. LDB >= max(N,1).
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