SUBROUTINE MVMRWK( N, M, X, LDX, Y, LDY )
*     .. 
*     .. Scalar Arguments ..
      INTEGER            LDY, LDX, M, N
*     ..
*     .. Array Arguments ..
      DOUBLE PRECISION   Y( LDY, * ), X( LDX, * )
*     ..
*
*  Purpose
*  =======
*
*  Compute
*
*               Y(:,1:M) = A*X(:,1:M)
*
*  The matrix is from a random walk example. The order of the random 
*  walk test matrix is N = (K+1)*(K+2)/2,  where K is the size of 
*  triangular random walk grid.
*
*  Arguments
*  =========
*
*  N       (input) INTEGER
*          The order of the matrix A.
*          N should be equal to (K+1)*(K+2)/2 for an integer K > 0.
*
*  M       (input) INTEGERS
*          The number of columns of X to multiply.
*
*  X       (input) REAL array, dimension ( LDX, M )
*          X contains the matrix X.
*
*  LDX     (input) INTEGER
*          The leading dimension of the array X, LDX >= max(1,N)
*
*  Y       (output) REAL array, dimension (LDY, M )
*          contains the product of the matrix A with X.
*
*  LDY     (input) INTEGER
*          The leading dimension of the array y, LDY >= max(1,N)
*
*  =====================================================================