#!/usr/bin/env python

def wathen_bandwidth ( nx, ny ):

#*****************************************************************************80
#
## WATHEN_BANDWIDTH returns the bandwidth of the WATHEN matrix.
#
#  Discussion:
#
#    The bandwidth measures the minimal number of contiguous diagonals,
#    including the central diagonal, which contain all the nonzero elements
#    of a matrix.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    31 August 2014
#
#  Author:
#
#    John Burkardt
#
#  Reference:
#
#    Nicholas Higham,
#    Algorithm 694: A Collection of Test Matrices in MATLAB,
#    ACM Transactions on Mathematical Software,
#    Volume 17, Number 3, September 1991, pages 289-305.
#
#    Andrew Wathen,
#    Realistic eigenvalue bounds for the Galerkin mass matrix,
#    IMA Journal of Numerical Analysis,
#    Volume 7, 1987, pages 449-457.
#
#  Parameters:
#
#    Input, integer NX, NY, values which determine the size of A.
#
#    Output, integer L, D, U, the lower, diagonal, and upper bandwidths 
#    of the matrix,
#
  l = 3 * nx + 4
  d = 1
  u = 3 * nx + 4

  return l, d, u

