#! /usr/bin/env python
#
def uu_product ( i, j, x ):

#*****************************************************************************80
#
## UU_PRODUCT: evaluate U(i,x)*U(j,x)
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    13 July 2015
#
#  Author:
#
#    John Burkardt
#
#  Parameters:
#
#    Input, integer I, J, the indices.
#
#    Input, real X, the argument.
#
#    Output, real VALUE, the value.
#
  from u_polynomial_value import u_polynomial_value

  value = 0.0
  for k in range ( abs ( i - j ), i + j + 1, 2 ):
    value = value + u_polynomial_value ( k, x )

  return value

def uu_product_test ( ):

#*****************************************************************************80
#
## UU_PRODUCT_TEST tests UU_PRODUCT.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license. 
#
#  Modified:
#
#    13 July 2015
#
#  Author:
#
#    John Burkardt
#
  import platform
  from i4_uniform_ab import i4_uniform_ab
  from r8_uniform_ab import r8_uniform_ab
  from u_polynomial_value import u_polynomial_value

  print ( '' )
  print ( 'UU_PRODUCT_TEST:' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  UU_PRODUCT(I,J;X) = U(I,X) * U(J,X)' )

  r8_lo = -1.0
  r8_hi = +1.0
  seed = 123456789

  print ( '' )
  print ( '   I   J      X               UI              UJ              UI*UJ       UU_PRODUCT' )
  print ( '' )
  for test in range ( 0, 10 ):
    x, seed = r8_uniform_ab ( r8_lo, r8_hi, seed )
    i, seed = i4_uniform_ab ( 0, 6, seed )
    ui = u_polynomial_value ( i, x )
    j, seed = i4_uniform_ab ( -1, 4, seed )
    uj = u_polynomial_value ( j, x )
    uiuj = uu_product ( i, j, x )
    print ( '  %2d  %2d  %14.6g  %14.6g  %14.6g  %14.6g  %14.6g'\
      % ( i, j, x, ui, uj, ui * uj, uiuj ) )
#
#  Terminate.
#
  print ( '' )
  print ( 'UU_PRODUCT_TEST:' )
  print ( '  Normal end of execution.' )
  return

if ( __name__ == '__main__' ):
  from timestamp import timestamp
  timestamp ( )
  uu_product_test ( )
  timestamp ( )