Matrix

Matrix, a simple Python class for managing matrices. Matrix supports various operations with matrices, like addition and multiplication.

Why?

• To consolidate my knowledge of Python classes
• To learn more about how matrices work
• To learn git basics

Supported operations

• Sum between matrices
• Subtraction between matrices
• Multiplication of a matrix by a number
• Multiplication between matrices
• Inverse matrix
• Symmetric and antisymmetric part
• Matrix of algebric complements
• Check if a matrix contains an certain number
• Equality and inequality test between matrices
• Transpose matrix
• Determinant of a matrix (Uses Laplace's theorem)

Usage

Importing the module and creating a matrix object

Python 3.6.2 (v3.6.2:5fd33b5, Jul  8 2017, 04:57:36) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from matrix import *
>>> m = Matrix(2, 3)
>>> m
[0, 0, 0]
[0, 0, 0]
>>>

Filling the matrix with random values

>>> m.random()
>>> m
[0, 28, 5]
[20, 7, 7]
>>>

You can also specify the range of the random values:

>>> m.random(1, 5)
>>> m
[5, 3, 4]
[1, 1, 5]
>>>

Basic matrix operations

>>> m * 3  # Multiplication
[15, 9, 12]
[3, 3, 15]
>>> m + 3  # Addition
[8, 6, 7]
[4, 4, 8]
>>> m - 5  # Subtraction
[0, -2, -1]
[-4, -4, 0]
>>>

Advanced matrix operations

>>> s = Matrix(3,3)  # We create a new square matrix
>>> s.random(1,5)
>>> s
[4, 1, 1]
[1, 2, 2]
[3, 2, 1]
>>> s.is_square()
True
>>> s.determinant()  # Calculating the determinant
-7
>>> s.transpose()  # Calculating the transpose matrix
[4, 1, 3]
[1, 2, 2]
[1, 2, 1]
>>> f = Matrix(3,3)
>>> f.random(-10, 10)
>>> f
[-1, 2, 1]
[5, -8, -6]
[-3, 5, 4]
>>> f.inverse_matrix()  # Calculate the inverse matrix
[2.0, 3.0, 4.0]
[2.0, 1.0, 1.0]
[-1.0, 1.0, 2.0]
>>> f.symmetric_part()  # Get the symmetric part
[-1.0, 3.5, -1.0]
[3.5, -8.0, -0.5]
[-1.0, -0.5, 4.0]
>>> f.antisymmetric_part()
[0.0, -1.5, 2.0]
[1.5, 0.0, -5.5]
[-2.0, 5.5, 0.0]
>>> f * s  # Product between matrices
[1, 5, 4]
[-6, -23, -17]
[5, 15, 11]
>>>

Accessing and modifying the elements of a matrix

>>> s[0]  # Get the first row
[4, 1, 1]
>>> s[0][2]  # Get the third element of the first row
1
>>> s[0][2] = 15  # Set the element (1, 3) as 15
>>> s
[4, 1, 15]
[1, 2, 2]
[3, 2, 1]
>>> 15 in s  # Check if the matrix contains a number
True
>>> del(s[1])  # Delete the second row
>>> s
[4, 1, 15]
[3, 2, 1]
>>> s.rows  # The dimensions are automatically updated
2
>>>

Contributions

Contributions are welcome! Please feel free to submit a Pull Request.