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IshitaTakeshi/file1.txt

Created August 4, 2014 03:15
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ガウス消去法をPythonで書いてみた ref: http://qiita.com/IshitaTakeshi/items/a89c700769148f1d4749
Raw
file1.txt
[ 1 2 0 -1]
[ 3 7 -1 3]
[ 2 2 1 2]
[ 1 2 0 -1]
[ 0 1 -1 6]
[ 2 2 1 2]
[ 1 2 0 -1]
[ 0 1 -1 6]
[ 0 -2 1 4]
[ 1 2 0 -1]
[ 0 1 -1 6]
[ 0 0 -1 16]
[ 1 2 0 -1]
[ 0 1 0 -10]
[ 0 0 -1 16]
[ 1 2 0 -1]
[ 0 1 0 -10]
[ 0 0 -1 16]
[ 1 0 0 19]
[ 0 1 0 -10]
[ 0 0 -1 16]
[ 1 0 0 19]
[ 0 1 0 -10]
[ 0 0 -1 16]
[ 1 0 0 19]
[ 0 1 0 -10]
[ 0 0 -1 16]
[ 1 0 0 19]
[ 0 1 0 -10]
[ 0 0 1 -16]
Raw
gaussian_elimination.py
from fractions import Fraction
import sys
import decimal
import numpy as np
def print_matrix(x):
for i in range(len(x)):
sys.stdout.write("[")
for j in range(len(x[i])):
m = Fraction(x[i][j]).limit_denominator()
sys.stdout.write("{!s:>8}".format(m))
sys.stdout.write("]\n")
sys.stdout.write("\n")
def gaussian_elimination(x):
x = np.float64(x)
N = x.shape[0]
print_matrix(x)
for i in range(N - 1):
for j in range(i + 1, N):
if(x[i][i] == 0):
continue
r = x[j][i] / x[i][i]
x[j] = x[j] - r * x[i]
print_matrix(x)
for i in reversed(range(N)):
for j in reversed(range(i)):
if(x[i][i] == 0):
continue
r = x[j][i] / x[i][i]
x[j] = x[j] - r * x[i]
print_matrix(x)
for i in range(N):
if(x[i][i] == 0):
continue
x[i] = x[i] / x[i][i]
print_matrix(x)
return x
if(__name__ == '__main__'):
x = [[1, 2, 0, -1],
[3, 7, -1, 3],
[2, 2, 1, 2]]
x = gaussian_elimination(x)
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