DLAGTM performs 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.

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

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 DOUBLE PRECISION


          The scalar alpha.  ALPHA must be 0., 1., or -1.; otherwise,


          it is assumed to be 0.

DL

          DL is DOUBLE PRECISION array, dimension (N-1)


          The (n-1) sub-diagonal elements of T.

D

          D is DOUBLE PRECISION array, dimension (N)


          The diagonal elements of T.

DU

          DU is DOUBLE PRECISION array, dimension (N-1)


          The (n-1) super-diagonal elements of T.

X

          X is DOUBLE PRECISION 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 DOUBLE PRECISION


          The scalar beta.  BETA must be 0., 1., or -1.; otherwise,


          it is assumed to be 1.

B

          B 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.

LDB

          LDB is INTEGER


          The leading dimension of the array B.  LDB >= max(N,1).

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

December 2016