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

#*****************************************************************************80
#
## faithful_histogram() histograms of Old Faithful eruption durations.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    25 September 2026
#
#  Author:
#
#    John Burkardt
#
  import matplotlib
  import numpy as np
  import platform

  print ( '' )
  print ( 'faithful_histogram():' )
  print ( '  matplotlib version: ' + matplotlib.__version__ )
  print ( '  numpy version:      ' + np.version.version )
  print ( '  python version:     ' + platform.python_version ( ) )
  print ( '  Histogram of Old Faithful eruption durations.' )
#
#  Set filenames.
#
  header = 'faithful'
  command_filename = header + '_commands.txt'
  data_filename = header + '_data.txt'
  graphic_filename = header + '_histogram.png'
#
#  Create commands.
#
  command_unit = open ( command_filename, 'wt' )

  command_unit.write ( '# ' + command_filename + '\n' )
  command_unit.write ( '#\n' )
  command_unit.write ( '# Usage:\n' )
  command_unit.write ( '#  gnuplot < ' + command_filename + '\n' )
  command_unit.write ( '#\n' )
  command_unit.write ( 'set term png\n' )
  command_unit.write ( 'set output "' + graphic_filename + '"\n' )
  command_unit.write ( 'set xlabel "<--- Duration --->"\n' )
  command_unit.write ( 'set ylabel "<--- Frequency --->"\n' )
  command_unit.write ( 'set title "Old Faithful Eruption Durations in Minutes"\n' )
  command_unit.write ( 'set grid\n' )
  command_unit.write ( 'set timestamp\n' )
  command_unit.write ( 'set style fill solid\n' )
  command_unit.write ( 'unset key\n' )
  command_unit.write ( 'binwidth = 5.0\n' )
  command_unit.write ( 'binstart = 40.0\n' )
  command_unit.write ( 'set boxwidth 0.9*binwidth\n' )
  command_unit.write ( 'plot "' + data_filename 
    + '" i 0 using (binwidth*(floor(($2-binstart)/binwidth)+0.5)+binstart):(1.0) smooth freq with boxes lc rgb "red"\n' )
  command_unit.write ( 'quit\n' )

  command_unit.close ( )
  print ( '  Created command file "' + command_filename + '"' )

  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 ( )
  faithful_histogram ( )
  timestamp ( )