CLAGTM 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 is CHARACTER*1
          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 is INTEGER
          The order of the matrix A.  N >= 0.

          NRHS is INTEGER
          The number of right hand sides, i.e., the number of columns
          of the matrices X and B.

          ALPHA is REAL
          The scalar alpha.  ALPHA must be 0., 1., or -1.; otherwise,
          it is assumed to be 0.

          DL is COMPLEX array, dimension (N-1)
          The (n-1) sub-diagonal elements of T.

          D is COMPLEX array, dimension (N)
          The diagonal elements of T.

          DU is COMPLEX array, dimension (N-1)
          The (n-1) super-diagonal elements of T.

          X is COMPLEX array, dimension (LDX,NRHS)
          The N by NRHS matrix X.

          LDX is INTEGER
          The leading dimension of the array X.  LDX >= max(N,1).

          BETA is REAL
          The scalar beta.  BETA must be 0., 1., or -1.; otherwise,
          it is assumed to be 1.

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