slaptm.f - Man Page

subroutine slaptm (n, nrhs, alpha, d, e, x, ldx, beta, b, ldb)
SLAPTM

SLAPTM

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.

Parameters

N

          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 1. or -1.; otherwise,
          it is assumed to be 0.

D

          D is REAL array, dimension (N)
          The n diagonal elements of the tridiagonal matrix A.

E

          E is REAL array, dimension (N-1)
          The (n-1) subdiagonal or superdiagonal elements of A.

X

          X is REAL 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

          B is 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

          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.

Definition at line 115 of file slaptm.f.