# This is a test script for the Euler solver written in Fortran
# To use it, simply do
# >> import test_f2pyEuler
# >> test_f2pyEuler.run()

import Numeric      # we need the Numeric module for proper interfacing with f2py
import f2pyEuler    # importing the Fortran extension module

# defining the derivative functions:
def f1(x,t):
    return x[0]*x[1]

def f2(x,t):
    return -x[0]*t

L = [f1,f2]  # this is the array of derivatives (represents the ODE)

# we now put a wrapper around the L array of functions so that we obtain
# a function compatible with our Fortran interface [result returned in place
# by an argument; index of function used also as argument]
def f(i,x,t):
    return L[i](x,t)

def fun(i,x,t,res):
    """fun(i,x,t,res) does res[0] = f(i,x,t)"""
    res[0] = f(i,x,t)
    return

# setting the initial conditions
# [the difference with before is that we now need to use Numeric.array
# since this is the data type used by f2py]
x = Numeric.array([1.0,2.0])
newx = Numeric.array(x)
t = 1.0
dt = 5.0

# the testing routine:
def run():
    f2pyEuler.euler(fun,x,t,dt,newx) # testing f2pyEuler extension!
    print "f2pyEuler.euler(fun,x,t,dt,newx) with fun(i,x,t,res) -> res[0] = L[i](x,t)"
    print "where L = [x[0]*x[1], -x[0]*t], x =", x, "t =", t, "and dt =", dt
    print "yields newx = ", newx
    print "This should be [11.0, -3.0] if everything works."