Python script to solve simultaneous equations with Gauss-Jorden(pivot) method.

gauss_jordern_pivot.py

#! /usr/local/bin/python3.6
"""
Simultaneous equations solving with Gauss-Jorden(pivot) method
"""
import math
import sys
import traceback


class GaussJordenPivot:
    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):
        """ Solving and display """
        try:
            self.__display_equations()
            for k in range(self.n):
                mx, s = 0, k
                for j in range(k, self.n):
                    if math.fabs(self.a[j][k]) <= mx:
                        continue
                    mx = math.fabs(self.a[j][k])
                    s = j
                if mx == 0:
                    print("解けない！")
                    sys.exit(0)
                for j in range(self.n + 1):
                    dummy = self.a[k][j]
                    self.a[k][j] = self.a[s][j]
                    self.a[s][j] = dummy
                p = self.a[k][k]
                for j in range(k, self.n + 1):
                    self.a[k][j] /= p
                for i in range(self.n):
                    if i == k:
                        continue
                    d = self.a[i][k]
                    for j in range(k, self.n + 1):
                        self.a[i][j] -= d * self.a[k][j]
            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 = GaussJordenPivot()
        obj.exec()
    except Exception as e:
        traceback.print_exc()
        sys.exit(1)