SLAPTM
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
November 2006
Purpose
SLAPTM multiplies an N by NRHS matrix X by a symmetric tridiagonal
matrix A and stores the result in a matrix B. The operation has the
form
B := alpha * A * X + beta * B
where alpha may be either 1. or -1. and beta may be 0., 1., or -1.
matrix A and stores the result in a matrix B. The operation has the
form
B := alpha * A * X + beta * B
where alpha may be either 1. or -1. and beta may be 0., 1., or -1.
Arguments
| 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) REAL
The scalar alpha. ALPHA must be 1. or -1.; otherwise,
it is assumed to be 0. |
| D |
(input) REAL array, dimension (N)
The n diagonal elements of the tridiagonal matrix A.
|
| E |
(input) REAL array, dimension (N-1)
The (n-1) subdiagonal or superdiagonal elements of A.
|
| 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).
|
| BETA |
(input) REAL
The scalar beta. BETA must be 0., 1., or -1.; otherwise,
it is assumed to be 1. |
| 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. |
| LDB |
(input) INTEGER
The leading dimension of the array B. LDB >= max(N,1).
|