Python script to solve simultaneous equations with Gauss elimination method.

gauss_elimination.py

#! /usr/local/bin/python3.6
"""
Simultaneous equations solving with Gauss elimination method
"""
import sys
import traceback


class GaussElimination:
    def __init__(self):
        self.a = [
            #[ 2, -3,  1,  5],
            #[ 1,  1, -1,  2],
            #[ 3,  5, -7,  0]
            [ 1, -2,  3, -4,  5],
            [-2,  5,  8, -3,  9],
            [ 5,  4,  7,  1, -1],
            [ 9,  7,  3,  5,  4]
        ]
        self.n = len(self.a)

    def exec(self):
        """ Execution """
        try:
            self.__display_equations()
            for k in range(self.n - 1):
                for i in range(k + 1, self.n):
                    d = self.a[i][k] / self.a[k][k]
                    for j in range(k + 1, self.n + 1):
                        self.a[i][j] -= self.a[k][j] * d
            for i in range(self.n - 1, -1, -1):
                d = self.a[i][self.n]
                for j in range(i + 1, self.n):
                    d -= self.a[i][j] * self.a[j][self.n]
                self.a[i][self.n] = d / self.a[i][i]
            self.__display_answers()
        except Exception as e:
            raise

    def __display_equations(self):
        """ Display of source equations """
        try:
            for i in range(self.n):
                for j in range(self.n):
                    print("{:+d}x{:d} ".format(self.a[i][j], j + 1), end="")
                print("= {:+d}".format(self.a[i][self.n]))
        except Exception as e:
            raise

    def __display_answers(self):
        """ Display of answer """
        try:
            for k in range(self.n):
                print("x{:d} = {:f}".format(k + 1, self.a[k][self.n]))
        except Exception as e:
            raise


if __name__ == '__main__':
    try:
        obj = GaussElimination()
        obj.exec()
    except Exception as e:
        traceback.print_exc()
        sys.exit(1)