Pymatrix module in python

Pymatrix is a lightweight matrix library which supports basic linear algebra operations. The elements in matrix should be numeric type to support basic algebra operations – int, float, rational, complex.

Instantiating Matrix

1. Using Matrix constructor
   Matrix can be initialised using constructor of Matrix class in pymatrix library.
   

Syntax: Matrix(rows, cols, fill=val(optional))
Parameters: 
rows – specify number of rows 
cols – specify number of columns 
fill – initialise all the elements with this value. It is an optional argument, the default fill is 0. 

1. Example:
   

Python3

import pymatrix


m = pymatrix.Matrix(2, 3, fill = '2')
print(m)

1. Output:
   

2 2 2
2 2 2

2. Using list of lists
   We can convert a list of lists into a matrix using the from_list() method where each list is treated as a row. Example- 
   

Python3

import pymatrix


list = [[1, 2, 3], [6, 4, 7], [3, 9, 1]]
m = pymatrix.Matrix.from_list(list)
print(m)

1. Output:
   

1 2 3
6 4 7
3 9 1

2. Using string
   We can convert a string into matrix object using from_string() method. The string is in triple quotes and each line is treated as a row. Example 
   

Python3

import pymatrix


string = '''1 2 3
       6 4 7
       3 9 1'''

m = pymatrix.Matrix.from_string(string)
print(m)

1. Output:
   

1 2 3
6 4 7
3 9 1

Matrix methods

Following are some of the methods provided in pymatrix library : 

• identity(n) – Creating an identity matrix of given size. This returns an object of Matrix class.
• is_square() – Checks whether given matrix is a square matrix or not. This returns a boolean value.
• is_invertible() – Checks whether given matrix is invertible or not. This returns a boolean value.
• inv() – Returns the inverse matrix if it exists, otherwise raises MatrixError exception.
• det() – Returns the determinant matrix if square matrix, otherwise raises MatrixError(‘non-square matrix does not have determinant’) exception.
• rank() – Returns the rank of matrix, rank is of integer type.
• trans() – Returns the transpose of the matrix.
• adjoint() – Returns the adjoint matrix.

Example:

Python3

# Python program for Matrix methods
from pymatrix import Matrix


# identity matrix of size 2
identity_matrix = Matrix.identity(2)
print('\nIdentity matrix :')
print(identity_matrix)

m = Matrix.from_list([[1,2,1],[2,1,1],[1,1,1]])

print('\nIs a square matrix :')
print(m.is_square())

print('\nIs an invertible matrix :')
print(m.is_invertible())

print('\nInverse :')
print(m.inv())

print('\nDeterminant :')
print(m.det())

print('\nRank :')
print(m.rank())

print('\nTranspose :')
print(m.trans())

print('\nAdjoint :')
print(m.adjoint())

Output:

Identity matrix :
1 0
0 1

Is a square matrix :
True

Is an invertible matrix :
True

Inverse :
 0.0  1.0 -1.0
 1.0  0.0 -1.0
-1.0 -1.0  3.0

Determinant :
-1.0

Rank :
3

Transpose :
1 2 1
2 1 1
1 1 1

Adjoint :
 0.0 -1.0  1.0
-1.0  0.0  1.0
 1.0  1.0 -3.0