#! /usr/bin/env python3
#
def test_digraph_arc_test ( ):

#*****************************************************************************80
#
## test_digraph_arc_test() tests test_digraph_arc().
#
#  Licensing:
#
#    This code is distributed under the MIT license. 
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  import platform

  print ( '' )
  print ( 'test_digraph_arc_test():' )
  print ( '  numpy version:      ' + np.version.version )
  print ( '  python version:     ' + platform.python_version ( ) )
  print ( '  Test test_digraph_arc().' )

  digraph_arc_example_abc_test ( )
  digraph_arc_example_abcd_test ( )
  digraph_arc_example_cycler_test ( )
  digraph_arc_example_five_test ( )
  digraph_arc_example_moler_test ( )
  digraph_arc_example_sauer_test ( )
  digraph_arc_example_sixty_test ( )
#
#  Terminate.
#
  print ( '' )
  print ( 'test_digraph_arc_test():' )
  print ( '  Normal end of execution.' )

  return

def digraph_arc_example_abc ( ):

#*****************************************************************************80
#
## digraph_arc_example_abc() returns the arc list for a 3-node example.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
#  Output:
#
#    integer L(3,2), the arc list.
#
  import numpy as np

  arc_num = 3

  L = np.array ( [ \
    [ 1, 2, 3 ], \
    [ 2, 3, 1 ] ] )

  return L

def digraph_arc_example_abc_test ( ):

#*****************************************************************************80
#
## digraph_arc_example_abc_test() tests digraph_arc_example_abc().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
  import pprint

  print ( '' )
  print ( 'digraph_arc_example_abc_test():' )
  print ( '  Test digraph_arc_example_abc()' )

  L = digraph_arc_example_abc ( )

  print ( '' )
  print ( '  "abc" arc list L:' )
  pprint.pprint ( L )

  return

def digraph_arc_example_abcd ( ):

#*****************************************************************************80
#
## digraph_arc_example_abcd() returns the arc list for a 4-node example.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
#  Output:
#
#    integer L(5,2), the arc list.
#
  import numpy as np

  arc_num = 5

  L = np.array ( [ \
    [ 1, 2, 3, 3, 4 ], \
    [ 2, 3, 1, 4, 1 ] ] )

  return

def digraph_arc_example_abcd_test ( ):

#*****************************************************************************80
#
## digraph_arc_example_abcd_test() tests digraph_arc_example_abcd().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
  import pprint

  print ( '' )
  print ( 'digraph_arc_example_abcd_test():' )
  print ( '  Test digraph_arc_example_abcd()' )

  L = digraph_arc_example_abcd ( )

  print ( '' )
  print ( '  "abcd" arc list L:' )
  pprint.pprint ( L )

  return

def digraph_arc_example_cycler ( ):

#*****************************************************************************80
#
## digraph_arc_example_cycler() returns the arc list for a 9-node example.
#
#  Diagram:
#  
#           A
#           V
#    9--><--7---<--3--><---4
#    |            /|      /
#    V           A |     /
#    |          /  |    /
#    5----<----1   V   A
#    |        /    |  /
#    V       A     | /
#    |      /      |/
#    2-->---8---<--6
#     \------>----/
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
#  Output:
#
#    integer L(16,2), the arc list.
#
  import numpy as np

  arc_num = 16

  L = np.array ( [ \
    [ 1, 1, 2, 2, 3, 3, 3, 4, 5, 6, 6, 7, 7, 8, 9, 9 ], \
    [ 3, 5, 6, 8, 4, 6, 7, 3, 2, 4, 8, 7, 9, 1, 5, 7 ] ] )

  return L

def digraph_arc_example_cycler_test ( ):

#*****************************************************************************80
#
## digraph_arc_example_cycler_test() tests digraph_arc_example_cycler().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
  import pprint

  print ( '' )
  print ( 'digraph_arc_example_cycler_test():' )
  print ( '  Test digraph_arc_example_cycler()' )

  L = digraph_arc_example_cycler ( )

  print ( '' )
  print ( '  "cycler" arc list L:' )
  pprint.pprint ( L )

  return

def digraph_arc_example_five ( ):

#*****************************************************************************80
#
## digraph_arc_example_five() returns the arc list for a 5-node example.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
#  Output:
#
#    integer L(5,2), the arc list.
#
  import numpy as np

  arc_num = 5

  L = np.array ( [ \
    [ 1, 2, 3, 4, 5 ], \
    [ 2, 5, 1, 1, 1 ] ] )

  return L

def digraph_arc_example_five_test ( ):

#*****************************************************************************80
#
## digraph_arc_example_five_test() tests digraph_arc_example_five().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
  import pprint

  print ( '' )
  print ( 'digraph_arc_example_five_test():' )
  print ( '  Test digraph_arc_example_five()' )

  L = digraph_arc_example_five ( )

  print ( '' )
  print ( '  "five" arc list L:' )
  pprint.pprint ( L )

  return

def digraph_arc_example_moler ( ):

#*****************************************************************************80
#
## digraph_arc_example_moler() returns the arc list for a network of Moler.
#
#  Discussion:
#
#    This matrix appears on page 5 of the reference.
#
#    We added a self-link for node 5, which otherwise has no outlinks.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
#  Reference:
#
#    Cleve Moler,
#    Experiments with Matlab,
#    Chapter 7: Google PageRank,
#    https://www.mathworks.com/moler/exm/chapters/pagerank.pdf
#
#  Output:
#
#    integer L(10,2), the arc list.
#
  import numpy as np

  arc_num = 10

  L = np.array ( [ \
    [ 1, 1, 2, 2, 3, 3, 3, 4, 5, 6 ], \
    [ 2, 6, 3, 4, 4, 5, 6, 1, 5, 1 ] ] )

  return L

def digraph_arc_example_moler_test ( ):

#*****************************************************************************80
#
## digraph_arc_example_moler_test() tests digraph_arc_example_moler().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
  import pprint

  print ( '' )
  print ( 'digraph_arc_example_moler_test():' )
  print ( '  Test digraph_arc_example_moler()' )

  L = digraph_arc_example_moler ( )

  print ( '' )
  print ( '  Moler arc list L:' )
  pprint.pprint ( L )

  return

def digraph_arc_example_sauer ( ):

#*****************************************************************************80
#
## digraph_arc_example_sauer() returns the arc list for the Sauer example.
#
#  Discussion:
#
#    This matrix appears on page 564 of the reference.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
#  Reference:
#
#    Timothy Sauer,
#    Numerical Analysis,
#    Pearson, 2006,
#    ISBN: 0-321-26898-9,
#    LC: QA297.S348
#
#  Output:
#
#    integer L(34,2), the arc list.
#
  import numpy as np

  arc_num = 34

  L = np.array ( [ \
    [ 5,  1,  3,  2,  4,  8,  2,  9,  3,  9, \
      2, 12,  3, 12,  1, 13,  5,  6,  7,  9, \
     14,  6,  7,  8, 12, 14,  4, 15, 10, 14, \
     13, 15, 11, 14 ],                       \
    [ 1,  2,  2,  3,  3,  4,  5,  5,  6,  6, \
      7,  7,  8,  8,  9,  9, 10, 10, 10, 10, \
     10, 11, 11, 11, 11, 11, 12, 12, 13, 13, \
     14, 14, 15, 15 ] ] )

  return L

def digraph_arc_example_sauer_test ( ):

#*****************************************************************************80
#
## digraph_arc_example_sauer_test() tests digraph_arc_example_sauer().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
  import pprint

  print ( '' )
  print ( 'digraph_arc_example_sauer_test()' )
  print ( '  Test digraph_arc_example_sauer()' )

  L = digraph_arc_example_sauer ( )

  print ( '' )
  print ( '  Sauer arc list L:' )
  pprint.pprint ( L )

  return

def digraph_arc_example_sixty ( ):

#*****************************************************************************80
#
## digraph_arc_example_sixty() sets the arc list for the sixty digraph.
#
#  Discussion:
#
#    The nodes of the digraph are divisors of 60.  There is a link from I to
#    J if divisor I can be divided by divisor J.
#
#  Licensing:
#
#    This code is distributed under the MIT license. 
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
#  Output:
#
#    integer L(54,2), the arc list.
#
  import numpy as np

  node_num = 12
  arc_num = 54
  L = np.zeros ( [ arc_num, 2 ] )

  d = np.array ( [ 60, 30, 20, 15, 12, 10, 6, 5, 4, 3, 2, 1 ], dtype = int )

  arc_id = 0
  for i in range ( 0, node_num ):
    for j in range ( 0, node_num ):
      if ( ( d[i] % d[j] ) == 0 ):
        L[arc_id,0] = i
        L[arc_id,1] = j
        arc_id = arc_id + 1

  return L

def digraph_arc_example_sixty_test ( ):

#*****************************************************************************80
#
## digraph_arc_example_sixty_test() tests digraph_arc_example_sixty().
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    17 April 2026
#
#  Author:
#
#    John Burkardt
#
  import pprint

  print ( '' )
  print ( 'digraph_arc_example_sixty_test():' )
  print ( '  Test digraph_arc_example_sixty()' )

  L = digraph_arc_example_sixty ( )

  print ( '' )
  print ( '  "sixty" arc list L:' )
  pprint.pprint ( L )

  return

def timestamp ( ):

#*****************************************************************************80
#
## timestamp() prints the date as a timestamp.
#
#  Licensing:
#
#    This code is distributed under the MIT license. 
#
#  Modified:
#
#    21 August 2019
#
#  Author:
#
#    John Burkardt
#
  import time

  t = time.time ( )
  print ( time.ctime ( t ) )

  return

if ( __name__ == '__main__' ):
  timestamp ( )
  test_digraph_arc_test ( )
  timestamp ( )