Polynom.py

An implementation for polynom objects, aiming to ease writing, making it as natural as possible.

How to use

You can instanciate a polynom using class constructor, as following:

P = Polynom(0, 4, 3) # P(X) = 4 X + 3 X^2
P = Polynom([0, 4, 3])
P = Polynom((0, 4, 3))

Of course, a Polynom object would not be of much use if it was not callable:

print P(3)
# 39

But the interesting part really starts with the definition of variable X, which you shall not change.

X = Polynom(1)

Why is that? Simply because once you have X, and using operators overloaded in class Polynom, you can now declare your polynoms using following writing:

P = 3 - X - 10 * X**2

or, if you prefer:

P = (3 + X) * (1 - 2 * X)

Operators

• __add__, +: do I need to explain?
• __neg__, - (unary)
• __sub__, - (binary)
• __mul__, *
• __pow__, **
• __div__, /

Only remains __floordiv__, or //, as well as __mod__, or %, as the quotient and remainder of the Euclidean division of two polynoms. For now, / is only supposed to divide every coefficient of the polynom by a scalar value.

String format

By default, casting a polynom to string will display the formula of the polynom, using "X" as the variable.

P = (3 + X) * (1 - 2 * X)
print "P(X) = %s" % P
# P(X) = 3 + -5 X + -2 X^2

Indeed, not as cute as it will be (zeros should be removed, and minus signs better handled), but it's a start.

Note

If you implement Complex numbers, class Polynom can work perfectly with them, as long as the basic operators are available.

First step?

i = ComplexNumber(0, 1)