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

# 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)

# importing the extension module:
import fEuler # we need fEuler.so or fEuler.pyd in the path...

# we define here a routine similar to the one that will be
# used from the 522 Simulator
def step(f,x,t,dt):
    # we need to change the way f is called (to be consistent with
    # new interface of the solver
    def fun(i,x1,t1):
        return f[i](x1,t1)
    return fEuler.step(fun,x,t,dt)

# setting the initial conditions:
x = [1,2]
t = 1.0
dt = 5.0

# the testing routine:
def run():
    newx = step(L,x,t,dt) # testing fEuler extension!
    print "step(f,x,t,dt) with f = [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."