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

#*****************************************************************************80
#
## vortex_subplots() plots a pair of subplots together.
#
#  Licensing:
#
#    This code is distributed under the MIT license.
#
#  Modified:
#
#    05 September 2026
#
#  Author:
#
#    John Burkardt
#
  import numpy as np
  import platform

  print ( '' )
  print ( 'vortex_subplots():' )
  print ( '  numpy version:  ' + np.version.version )
  print ( '  python version: ' + platform.python_version ( ) )
  print ( '  Plot a pair of subplots together using gnuplot().' )

  command_filename = 'vortex_commands.txt'
  command_unit = open ( command_filename, 'wt' )

  command_unit.write ( '# vortex_commands.txt\n' )
  command_unit.write ( '#\n' )
  command_unit.write ( '# Usage:\n' )
  command_unit.write ( '#  gnuplot < vortex_commands.txt\n' )
  command_unit.write ( '#\n' )
  command_unit.write ( 'set term png\n' )
  command_unit.write ( 'set output "vortex_subplots.png"\n' )
  command_unit.write ( 'set multiplot layout 1,2 title "Vortex pressure and velocity"\n' )

  command_unit.write ( '#\n' )
  command_unit.write ( 'set xlabel "<--- X --->"\n' )
  command_unit.write ( 'set ylabel "<--- Y --->"\n' )
  command_unit.write ( 'set title "Pressure"\n' )
  command_unit.write ( 'set grid\n' )
  command_unit.write ( 'set timestamp\n' )
  command_unit.write ( 'unset key\n' )
  command_unit.write ( 'unset surface\n' )
  command_unit.write ( 'set contour base\n' )
  command_unit.write ( 'set view map\n' )
  command_unit.write ( 'set pm3d\n' )
  command_unit.write ( 'set size ratio -1\n' )
  command_unit.write ( 'unset tics\n' )
  command_unit.write ( 'set view map scale 0.90\n' )
  command_unit.write ( 'splot "vortex_pressure_data.txt" with pm3d\n' )

  command_unit.write ( '#\n' )
  command_unit.write ( 'set xlabel "<--- X --->"\n' )
  command_unit.write ( 'set ylabel "<--- Y --->"\n' )
  command_unit.write ( 'set title "Velocity"\n' )
  command_unit.write ( 'unset key\n' )
  command_unit.write ( 'set grid\n' )
  command_unit.write ( 'set size ratio -1\n' )
  command_unit.write ( 'plot "vortex_velocity_data.txt" using 1:2:5:6 with vectors head filled lt 2 linecolor rgb "blue"\n' )

# command_unit.write ( 'plot "vortex_velocity_data.txt" using 1:2:5:6 with vectors \\\n' )
# command_unit.write ( '  head filled lt 2 linecolor rgb "blue"\n' )

  command_unit.write ( '#\n' );
  command_unit.write ( 'unset multiplot\n' );
  command_unit.write ( 'quit\n' )

  command_unit.close ( )
  print ( '  Created command file "vortex_subplots_commands.txt"' )
#
#  Terminate.
#
  print ( '' )
  print ( 'vortex_subplots():' )
  print ( '  Normal end of execution.' )

  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 ( )
  vortex_subplots ( )
  timestamp ( )