function check = normal_check ( mu, sigma )

%*****************************************************************************80
%
%% NORMAL_CHECK checks the parameters of the Normal PDF.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    17 September 2004
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, real MU, SIGMA, the parameters of the PDF.
%    SIGMA nonzero.
%
%    Output, logical CHECK, is true if the parameters are legal.
%
  if ( sigma == 0.0 )
    fprintf ( 1, '\n' );
    fprintf ( 1, 'NORMAL_CHECK - Fatal error!\n' );
    fprintf ( 1, '  SIGMA == 0.\n' );
    check = false;
    return
  end

  check = true;

  return
end
