Functions

Unlike c/c++, Python functions do not have separate header files or interface/implementation sections like Pascal/Fortran.

A function is simply defined using:

def f(u,v):
    t = u - v
    return t

As we are targeting a strongly typed language, unfortunately, the first thing to do is to add a header as the following:

#$ header f(double, double) results(double)
def f(u,v):
    t = u - v
    return t

this tells Pyccel that the input/output arguments are of double precision type.

You can then call f even in a given expression:

x1 = 1.0
y1 = 2.0

w    = 2 * f(x1,y1) + 1.0

You can also define functions with multiple lhs and call them as in the following example:

#$ header g(double, double)
def g(x,v):
    m = x - v
    t =  2.0 * m
    z =  2.0 * t
    return t, z

x1 = 1.0
y1 = 2.0

z, t = g(x1,y1)