Python/linear_algebra
Tianyi Zheng a64c9f1e7c
Deduplicate euclidean_length method in Vector (#5658)
* Rewrite parts of Vector and Matrix methods

* Refactor determinant method and add unit tests

Refactor determinant method to create separate minor and cofactor
methods.
Add respective unit tests for new methods.
Rename methods using snake case to follow Python naming conventions.

* Reorganize Vector and Matrix methods

* Update linear_algebra/README.md

Co-authored-by: John Law <johnlaw.po@gmail.com>

* Fix punctuation and wording

* Apply suggestions from code review

Co-authored-by: John Law <johnlaw.po@gmail.com>

* Deduplicate euclidean length method for Vector

* Add more unit tests for Euclidean length method

* Fix bug in unit test for euclidean_length

* Remove old comments for magnitude method

Co-authored-by: John Law <johnlaw.po@gmail.com>
2021-10-31 22:16:02 +08:00
..
src Deduplicate euclidean_length method in Vector (#5658) 2021-10-31 22:16:02 +08:00
__init__.py Add __init__.py files in all the directories (#2503) 2020-09-28 19:42:36 +02:00
README.md Rewrite parts of Vector and Matrix (#5362) 2021-10-27 11:48:43 +08:00

Linear algebra library for Python

This module contains classes and functions for doing linear algebra.


Overview

class Vector

    • This class represents a vector of arbitrary size and related operations.

    Overview of the methods:

    • constructor(components) : init the vector
    • set(components) : changes the vector components.
    • __str__() : toString method
    • component(i): gets the i-th component (0-indexed)
    • __len__() : gets the size / length of the vector (number of components)
    • euclidean_length() : returns the eulidean length of the vector
    • operator + : vector addition
    • operator - : vector subtraction
    • operator * : scalar multiplication and dot product
    • copy() : copies this vector and returns it
    • change_component(pos,value) : changes the specified component
  • function zero_vector(dimension)

    • returns a zero vector of 'dimension'
  • function unit_basis_vector(dimension, pos)

    • returns a unit basis vector with a one at index 'pos' (0-indexed)
  • function axpy(scalar, vector1, vector2)

    • computes the axpy operation
  • function random_vector(N, a, b)

    • returns a random vector of size N, with random integer components between 'a' and 'b' inclusive

class Matrix

    • This class represents a matrix of arbitrary size and operations on it.

    Overview of the methods:

    • __str__() : returns a string representation
    • operator * : implements the matrix vector multiplication implements the matrix-scalar multiplication.
    • change_component(x, y, value) : changes the specified component.
    • component(x, y) : returns the specified component.
    • width() : returns the width of the matrix
    • height() : returns the height of the matrix
    • determinant() : returns the determinant of the matrix if it is square
    • operator + : implements the matrix-addition.
    • operator - : implements the matrix-subtraction
  • function square_zero_matrix(N)

    • returns a square zero-matrix of dimension NxN
  • function random_matrix(W, H, a, b)

    • returns a random matrix WxH with integer components between 'a' and 'b' inclusive

Documentation

This module uses docstrings to enable the use of Python's in-built help(...) function. For instance, try help(Vector), help(unit_basis_vector), and help(CLASSNAME.METHODNAME).


Usage

Import the module lib.py from the src directory into your project. Alternatively, you can directly use the Python bytecode file lib.pyc.


Tests

src/tests.py contains Python unit tests which can be run with python3 -m unittest -v.