Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Simple Python matrix inversion script
#!/usr/bin/env python3
# -*-coding:utf-8 -*
"""
@author: HorlogeSkynet
"""
import os
import numpy as np
def clearScreen():
os.system('cls' if os.name == 'nt' else 'clear')
def printPartialMatrix(matrice, n, i, j):
clearScreen()
print("\n\nPlease enter the values in the matrice:\n")
for _y in range(1, n + 1, 1):
print("\t[{}]".format(_y), end='')
print()
for _x in range(0, i + 1, 1):
print("\n[{}]".format(_x + 1), end='\t')
if _x == i:
for _y in range(0, j, 1):
print("{}".format(matrice[_x][_y]), end='\t')
else:
for _y in range(0, n, 1):
print("{}".format(matrice[_x][_y]), end='\t')
def promptMatrix(matrice, n):
for _i in range(0, n, 1):
for _j in range(0, n, 1):
printPartialMatrix(matrice, n, _i, _j)
matrice[_i][_j] = input()
def printMatrix(matrice, n, param):
if param:
print("\t\t", end = '')
for _y in range(1, n + 1, 1):
print("\t[{}]".format(_y), end='')
print()
for _x in range(0, n, 1):
if param:
if _x == n // 2:
print("\n(1 / {}) * ".format(param), end='\t')
else:
print("\n", end='\t\t')
else:
print()
print("[{}]".format(_x + 1), end='\t')
for _y in range(0, n, 1):
print("{}".format(matrice[_x][_y]), end='\t')
def zerosFinder(matrice, n):
# Let's find the line and the column which got the less '0' than others
line = 0
column = 0
maxZero_l = -1
maxZero_c = -1
for _i in range(0, n, 1):
zero_l = 0
zero_c = 0
for _j in range(0, n, 1):
if matrice[_i][_j] == 0:
zero_l += 1
if matrice[_j][_i] == 0:
zero_c += 1
if zero_l > maxZero_l:
maxZero_l = zero_l
line = _i
if zero_c > maxZero_c:
maxZero_c = zero_c
column = _i
return line, column
def determinant(matrice, n):
_value = 0
if n == 2:
# Here: let's just return 'det(M) = (a * d) - (b * c)'
return (matrice[0][0] * matrice[1][1]) - (matrice[1][0] * matrice[0][1])
else:
line, column = zerosFinder(matrice, n)
newMatrice = np.zeros((n - 1, n - 1))
if line > column:
for _y in range(0, n, 1):
_u = 0
_v = 0
for _i in range(0, n, 1):
for _j in range(0, n, 1):
if _i != line and _j != _y:
newMatrice[_u][_v] = matrice[_i][_j]
if _v == (n - 1) - 1:
_u += 1
_v = 0
else:
_v += 1
_value += matrice[line][_y] * (-1)**(line + _y) * determinant(newMatrice, n - 1)
else:
for _x in range(0, n, 1):
_u = 0
_v = 0
for _i in range(0, n, 1):
for _j in range(0, n, 1):
if _j != column and _i != _x:
newMatrice[_u][_v] = matrice[_i][_j]
if _v == (n - 1) - 1:
_u += 1
_v = 0
else:
_v += 1
_value += matrice[_x][column] * (-1)**(_x + column) * determinant(newMatrice, n - 1)
return _value
def inverse(matrice, n, determinant):
matrice = transposee(comatrice(matrice, n), n)
printMatrix(matrice, n, determinant)
def comatrice(matrice, n):
coMatrice = np.zeros((n, n))
if n > 2:
newMatrice = np.zeros((n - 1, n - 1))
for _i in range(0, n, 1):
for _j in range(0, n, 1):
_u = 0
_v = 0
for _x in range(0, n, 1):
for _y in range(0, n, 1):
if _x != _i and _y != _j:
newMatrice[_u][_v] = matrice[_x][_y]
if _v == (n - 1) - 1:
_u += 1
_v = 0
else:
_v += 1
coMatrice[_i][_j] = (-1)**(_i + _j) * determinant(newMatrice, n - 1)
else:
coMatrice[0][0], coMatrice[1][1] = matrice[1][1], matrice[0][0]
coMatrice[0][1], coMatrice[1][0] = (-1) * matrice[1][0], (-1) * matrice[0][1]
return coMatrice
def transposee(matrice, n):
for _i in range(0, n, 1):
for _j in range(_i + 1, n, 1):
matrice[_i][_j], matrice[_j][_i] = matrice[_j][_i], matrice[_i][_j]
return matrice
def trace(matrice, n):
trace = 0
for _i in range(0, n, 1):
trace += matrice[_i][_i]
return trace
if __name__ == '__main__':
clearScreen()
n = 0
while n <= 1:
n = abs(int(input("\nSquare matrice dimension: ")))
matrice = np.zeros((n, n))
promptMatrix(matrice, n)
clearScreen()
print("\n-> M:\n")
printMatrix(matrice, n, False)
value = determinant(matrice, n)
print("\n\n\n-> Det(M) = {}.\n".format(value))
if value != 0:
print("\n-> M^⁻¹:\n")
inverse(matrice, n, value)
else:
print("\n-> Indeed, M is not invertible.", end='')
print("\n\n\n-> tr(M): {}.\n\n\n".format(trace(matrice, n)))
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.