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

## euler_solve_logistic() tests euler_solve() on the logistic ODE.

  from euler_solve import euler_solve
  import matplotlib.pyplot as plt
  import numpy as np

  print ( '' )
  print ( 'euler_solve_logistic():' )
#
#  Input to euler_solve:
#
  def logistic_dydt ( t, y ):
    dydt = y * ( 1.0 - y )
    return dydt
  tspan = np.array ( [ 0., 5.0 ] )
  y0 = 0.01
  n = 50
#
#  Solve.
#
  t, y = euler_solve ( logistic_dydt, tspan, y0, n )
#
#  Plot.
#
  plt.plot ( t, y, 'b-', linewidth = 3 )
  plt.grid ( True )
  filename = 'euler_solve_logistic.png'
  plt.savefig ( filename )
  plt.show ( )
  print ( '  Graphics saved as "' + filename + '"' )
  
if ( __name__ == "__main__" ):
  euler_logistic_test ( )