#!/usr/bin/env python def rnglib_test03 ( ): #*****************************************************************************80 # ## RNGLIB_TEST03 demonstrates how the seed can be reset to its initial or last value. # # Licensing: # # This code is distributed under the GNU LGPL license. # # Modified: # # 27 May 2013 # # Author: # # John Burkardt # from cgn_set import cgn_set from init_generator import init_generator from initialize import initialize from r4_uniform_01 import r4_uniform_01 print '' print 'RNGLIB_TEST03' print ' R4_UNIFORM_01 ( ) returns a random real number' print ' in [0,1] using the current generator.' # # Initialize the package. # print '' print ' INITIALIZE initializes the random number generator.' print ' It only needs to be called once before using the package.' initialize ( ) print '' print ' INIT_GENERATOR can reset the seed to the initial value,' print ' the last (previous) value, or a new seed.' # # Set the current generator index to 17. # g = 17 cgn_set ( g ) print '' print ' Current generator index = %d' % ( g ) # # Force the current generator to begin at its initial seed. # print '' print ' INIT_GENERATOR ( 0 ) starts at the initial seed.' init_generator ( 0 ) print '' print ' I R4_UNIFORM_01 ( )' print '' for i in range ( 1, 10 ): u = r4_uniform_01 ( ) print ' %2d %14.6g' % ( i, u ) print '' print ' Calling INIT_GENERATOR ( 0 ) again restarts' print ' at the initial seed.' init_generator ( 0 ) print '' print ' I R4_UNIFORM_01 ( )' print '' for i in range ( 1, 10 ): u = r4_uniform_01 ( ) print ' %2d %14.6g' % ( i, u ) print '' print ' Calling INIT_GENERATOR ( 2 ) restarts' print ' at a new "far ahead" seed.' init_generator ( 2 ) print '' print ' I R4_UNIFORM_01 ( )' print '' for i in range ( 1, 10 ): u = r4_uniform_01 ( ) print ' %2d %14.6g' % ( i, u ) print '' print ' Calling INIT_GENERATOR ( 1 ) restarts' print ' at the last seed (in this case, the "far ahead"' print ' seed specified on the previous call.)' print '' print ' I R4_UNIFORM_01 ( )' print '' for i in range ( 1, 11 ): u = r4_uniform_01 ( ) print ' %2d %14.6g' % ( i, u ) if ( ( i % 3 ) == 0 ): init_generator ( 1 ) print ' (Reset to last seed)' if ( __name__ == '__main__' ): rnglib_test03 ( )