# -*- coding: UTF-8 -*-
class ClassGauss(object):
def __init__(self, a, b):
super(ClassGauss, self).__init__()
self.a = a
self.b = b
self.n = len(self.b)
def max(self, max_i, max_v, i, j):# get max
a = self.a
abs_of_a = abs(a[i][j])
if max_v < abs_of_a:
max_v = abs_of_a
max_i = i
return max_i, max_v
def swap(self, ai, j):# change line
a = self.a
b = self.b
n = self.n
for i in range(0, n):
temp = a[ai][i]
a[ai][i] = a[j][i]
a[j][i] = temp
tempb = b[ai]
b[ai] = b[j]
b[j] = tempb
def gauss(self):
n = self.n
max_i = 0 # line num of max value
max_v = m = self.a[0][0]
for j in range(0, n-1):
for i in range(j, n):
max_i, max_v = self.max(max_i, max_v, i, j)
if max_v == 0:
raise ValueError('no unique solution')
if debug:
print('max_v = %f' % max_v)
print('max_i = %f , j = %f' % (max_i, j))
if max_i != j:
# jiaohuan ai hang he ajhang
self.swap(max_i, j)
if debug:
print('SWAP*******')
print(self.a)
print(self.b)
for p in range(j+1, n):
l = a[p][j] / a[j][j]
# print('l = %f' % (l))
b[p] -= l * b[j]
for q in range(j, n):
a[p][q] -= l * a[j][q]
if debug:
print('CAL_a******')
print(self.a)
print(self.b)
max_v = m
if debug:
print("************************")
print(self.a)
print(self.b)
self.calculate()
def calculate(self):
n = self.n - 1
xn = b[n] / a[n][n]
print('xn = %f'% xn)
if __name__ == '__main__':
# example1
a = [[0.012, 0.0100, 0.1670],
[1.000, 0.8334, 5.910],
[3200, 1200, 4.200]]
b = [0.6781, 12.10, 983.3]
debug = False
# example2
# a = [[2.00, -4.00, 2.00],[1.00, 2.00, 3.00],[-3.00, -2.00, 5.00]]
# b = [2.00, 3.00, 1.00]
g = ClassGauss(a,b)
g.gauss()
