#! /usr/bin/env python
#
def r8row_compare ( m, n, a, i, j ):

#*****************************************************************************80
#
## R8ROW_COMPARE compares rows in an R8ROW.
#
#  Discussion:
#
#    An R8ROW is an M by N array of R8's, regarded as an array of M rows,
#    each of length N.
#
#  Example:
#
#    Input:
#
#      M = 4, N = 3, I = 2, J = 4
#
#      A = (
#        1  5  9
#        2  6 10
#        3  7 11
#        4  8 12 )
#
#    Output:
#
#      VALUE = -1
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    28 February 2016
#
#  Author:
#
#    John Burkardt
#
#  Parameters:
#
#    Input, integer M, N, the number of rows and columns.
#
#    Input, real A(M,N), the M by N array.
#
#    Input, integer I, J, the rows to be compared.
#    I and J must be between 0 and M-1.
#
#    Output, integer VALUE, the results of the comparison:
#    -1, row I < row J,
#     0, row I = row J,
#    +1, row J < row I.
#
  from sys import exit
#
#  Check.
#
  if ( i < 0 or m <= i ):
    print ''
    print 'R8ROW_COMPARE - Fatal error!'
    print '  Row index I is out of bounds.'
    print '  I = %d' % ( i )
    exit ( 'R8ROW_COMPARE - Fatal error!' )

  if ( j < 0 or m <= j ):
    print ''
    print 'R8ROW_COMPARE - Fatal error!'
    print '  Row index J is out of bounds.'
    print '  J = %d' % ( j )
    exit ( 'R8ROW_COMPARE - Fatal error!' )

  value = 0

  if ( i == j ):
    return value

  k = 0

  while ( k < n ):

    if ( a[i,k] < a[j,k] ):
      value = -1
      return value
    elif ( a[j,k] < a[i,k] ):
      value = +1
      return value

    k = k + 1

  return value

def r8row_compare_test ( ):

#*****************************************************************************80
#
## R8ROW_COMPARE_TEST tests R8ROW_COMPARE.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    28 February 2016
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  from i4mat_print import i4mat_print
  from r8row_print import r8row_print

  print ''
  print 'R8ROW_COMPARE_TEST'
  print '  R8ROW_COMPARE compares rows of an R8ROW,'
  print '  returning -1, 0 or +1 for comparison.'

  m = 6
  n = 5
 
  a = np.zeros ( [ m, n ] )

  for j in range ( 0, n ):
    for i in range ( 0, m ):
      a[i,j] = ( ( i + j ) % 3 )

  r8row_print ( m, n, a, '  Matrix A:' )

  c = np.zeros ( [ m, m ] )

  for j in range ( 0, m ):
    for i in range ( 0, m ):
      c[i,j] = r8row_compare ( m, n, a, i, j )

  i4mat_print ( m, m, c, '  C(I,J) = Row I compare Row J:' )
#
#  Terminate.
#
  print ''
  print 'R8ROW_COMPARE_TEST:'
  print '  Normal end of execution.'
  return

if ( __name__ == '__main__' ):
  from timestamp import timestamp
  timestamp ( )
  r8row_compare_test ( )
  timestamp ( )