loops_and_conditional_tracing.py

def forward_fn(x):
    for n in range(5):
        if n % 2 == 0:
            x = 3.*x
        else:
            x = x**(1./n) + 1./n

    return x

x = Variable(2.)
y = forward_fn(x)
print(y)

y.backward()
print(x)