numpoly 0.0.7

Polynomials as a numpy datatype

Numpoly is a generic library for creating, manipulating polynomial arrays.

numpoly is a subclass of numpy.ndarray and as such is compatible with most numpy functions, where that makes sense.

Table of Contents:

• Installation

• Example usage

• Development

• Questions & Troubleshooting

Installation

Installation should be straight forward:

pip install numpoly

And you should be ready to go.

Example usage

Constructing polynomial is typically done using one of the available constructors:

>>> poly1 = numpoly.monomial(("x", "y"), start=0, stop=3)
>>> print(poly1)
[1 y x x*y x**2 y**2 y**3 x*y**2 x**2*y x**3]

It is also possible to construct your own from symbols:

>>> x, y = numpoly.symbols("x y")
>>> poly2 = numpoly.polynomial([1, x**2-1, x*y, y**2-1])
>>> print(poly2)
[1 -1+x**2 x*y -1+y**2]

Or in combination with other numpy objects:

>>> poly3 = x**numpy.arange(4)-y**numpy.arange(3, -1, -1)
>>> print(poly3)
[1-y**3 -y**2+x -y+x**2 -1+x**3]

The polynomials can be evaluated as needed:

>>> print(poly1(1, 2))
[1 2 1 2 1 4 8 4 2 1]
>>> print(poly2(x=[1, 2]))
[[1 1]
 [0 3]
 [y 2*y]
 [-1+y**2 -1+y**2]]
>>> print(poly1(x=y, y=2*x))
[1 2*x y 2*x*y y**2 4*x**2 8*x**3 4*x**2*y 2*x*y**2 y**3]

The polynomials also support many numpy operations:

>>> print(numpy.reshape(poly2, (2, 2)))
[[1 -1+x**2]
 [x*y -1+y**2]]
>>> print(poly1[::3].astype(float))
[1.0 x*y y**3 x**3]
>>> print(numpy.sum(poly1.reshape(2, 5), 0))
[1+y**2 y+y**3 x+x*y**2 x*y+x**2*y x**2+x**3]

There are also several polynomial specific operators:

>>> print(numpoly.diff(poly3, y))
[-3*y**2 -2*y -1 0]
>>> print(numpoly.gradient(poly3))
[[0 1 2*x 3*x**2]
 [-3*y**2 -2*y -1 0]]

Development

Development is done using Poetry manager. Inside the repository directory, install and create a virtual enviroment with:

poetry install

To run tests, run:

poentry run pytest numpoly test --doctest-modules

Questions & Troubleshooting

For any problems and questions you might have related to numpoly, please feel free to file an issue.