function phi4_test ( )

%*****************************************************************************80
%
%% PHI4_TEST tests PHI4.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    04 June 2018
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    William Press, Brian Flannery, Saul Teukolsky, William Vetterling,
%    Numerical Recipes in FORTRAN: The Art of Scientific Computing,
%    Third Edition,
%    Cambridge University Press, 2007,
%    ISBN13: 978-0-521-88068-8,
%    LC: QA297.N866.
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'PHI4_TEST\n' );
  fprintf ( 1, '  PHI4 evaluates the Gaussian radial basis function.\n' );

  nd = 5;

  r = [ 1; 2; 3; 4; 5 ];
  r8vec_print ( nd, r, '  R:' );

  r0 = 4.0;
  fprintf ( 1, '  R0 = %g\n', r0 );

  v = phi4 ( r, r0 );
  r8vec_print ( nd, v, '  PHI4(R,R0) = Gaussian:' );

  return
end

