#! /usr/bin/env python
#
def ubvec_unrank_grlex ( rank, n ):

#*****************************************************************************80
#
## UBVEC_UNRANK_GRLEX unranks a UBVEC using the GRLEX ordering.
#
#  Discussion:
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    23 November 2015
#
#  Author:
#
#    John Burkardt
#
#  Parameters:
#
#    Input, integer RANK, the rank.
#    0 <= RANK < 2^N.
#
#    Input, integer N, the size of the BVEC.
#
#    Output, integer B(N), the UBVEC of the given rank.
#
  import numpy as np
  from i4_choose import i4_choose
  from ksubset_colex_unrank import ksubset_colex_unrank
  from ubvec_reverse import ubvec_reverse
  from sys import exit

  mk = 0

  for k in range ( 0, n + 1 ):

    mk_old = mk
    mk_plus = i4_choose ( n, k )
    mk = mk_old + mk_plus

    if ( rank < mk ):
      rank_k = rank - mk_old
      t = ksubset_colex_unrank ( rank_k, k, n )
      c = np.zeros ( n )
      for i in range ( 0, k ):
        c[t[i]-1] = 1
      
      b = ubvec_reverse ( n, c )
      return b
#
#  If we got here, the rank is too large.
#
  print ( '' )
  print ( 'UBVEC_UNRANK_GRLEX - Fatal error!' )
  print ( '  Input value of rank is too high.' )
  exit ( 'UBVEC_UNRANK_GRLEX - Fatal error!' )

def ubvec_unrank_grlex_test ( ):

#*****************************************************************************80
#
## UBVEC_UNRANK_GRLEX_TEST tests UBVEC_UNRANK_GRLEX.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license. 
#
#  Modified:
#
#    23 November 2015
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  import platform

  n = 4

  print ( '' )
  print ( 'UBVEC_UNRANK_GRLEX_TEST' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  UBVEC_UNRANK_GRLEX returns the UBVEC of given rank' )
  print ( '  in the graded lexicographical ordering.' )

  s = -1

  for rank in range ( 0, 16 ):
    b = ubvec_unrank_grlex ( rank, n )
    if ( s < np.sum ( b ) ):
      print ( '  --  --------' )
      s = np.sum ( b )
    print ( '  %2d  ' % ( rank ), end = '' )
    for j in range ( 0, n ):
      print ( '%2d' % ( b[j] ), end = '' )
    print ( '' )
#
#  Terminate.
#
  print ( '' )
  print ( 'UBVEC_UNRANK_GRLEX_TEST' )
  print ( '  Normal end of execution.' )
  return

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