mathmatrix 0.2

A package for Python that lets you create and perform various operations on Matrices sucjh as finding the adjoint, inverse, determinant of a matrix, etc..

• Addition, Multiplication, Division, Subraction operations supported between matrices and between a matrix and a int / float

• Calculates:

  • Determinant

  • Inverse

  • Cofactor of a given element in the Matrix

  • Adjoint

Getting started

Creating a Matrix

To create a matrix, specify the order of the Matrix (mxn) where the first argument (m) is the number of rows in the matrix and the second argument (n) is the number of columns

We can use a nested list to represent a Matrix during initialization of an object In a nested list, the length of the outer list would be ‘m’ and the number of elements the inner lists have would be ‘n’

from matrix import Matrix

matrix_list = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]

matrix1 = Matrix(3, 3, matrix_list)

print(matrix1)
#Prints:
# [ 1, 2, 3
#   4, 5, 6
#   7, 8, 9 ]

Addition and Subraction

We can add and subract matrices extremely easily:

matrix_list2 = [
    [0, 1, 3],
    [5, 2, 7],
    [7, 1, 9]
]
matrix2 = Matrix(3, 3, matrix_list2)
matrix3 = matrix1 + matrix2
print(matrix3)
#Prints:
# [ 1, 3, 6
#   9, 7, 13
#   14, 9, 18 ]

Adding an int / float to a matrix will perform the operation on all elements of the matrix and return a new matrix

matrix4 = matrix1 + 5
print(matrix4)
#Prints:
# [ 6, 7, 8
#   9, 10, 11
#   12, 13, 14 ]
# Same way,
print(matrix4 - matrix1)
# [ 5, 5, 5
#   5, 5, 5
#   5, 5, 5 ]
print(matrix1 - 3)
#Prints:
# [ -2, -1, 0
#   1, 2, 3
#   4, 5, 6 ]

Multiplication and Division

Matrix multiplication can only be implemented if the number of columns in the first matrix is equal to the number of rows in the other matrix. Basically: A m x n Matrix can only be multiplied with a n x l Matrix .

The order of the resultant Matrix will be m x l

Example:

# m x n * n x l : Gives l x m
# 2 x 3 * 3 x 2 : Gives 2 x 2
# 2 x 3 * 4 x 2 : Cannot mutliply

Internally, division is calculated by multiplying a matrix and the inverse of the other matrix therefore the same condition applies for division

print(matrix1 * 5)
# [ 5, 10, 15
#   20, 25, 30
#   35, 40, 45 ]
print(matrix1 * matrix2)