kaif

from __future__ import unicode_literals
from math import *
import random
import os

def comment(s):
if s.find("#") != -1:
s = s[:s.find("#")]
return s.strip()

clear = lambda: os.system('cls')

# x^2 - 2y
runge = lambda x, y: x*x - 2*y

# try:
f = open('data.dat','rt')

a = float(comment(f.readline())) # a (начало отрезка)
b = float(comment(f.readline())) # b (конец отрезка)
n = int(comment(f.readline())) # n (количество разбиений отрезка)
h = float((b - a) / n) # h (шаг)

x = float(comment(f.readline()))
y = float(comment(f.readline()))
xn, yn = x, y
print("x[0] = {0}\ny[0] = {1}".format( x, y ))

i = 1
while(x < b):
x = xn + i * h
k1 = runge( x, y )
k2 = runge( x + .5 * h, y + .5 * h * k1 )
k3 = runge( x + .5 * h, y + .5 * h * k2 )
k4 = runge( x + h, y + h * k3 )
dy = ( k1 + 2*k2 + 2*k3 + k4 ) * h/6
y = y + dy
print("""x[{0}] = {1}
y[{0}] = {2}
y[{0}](точное) = {8}
k1[{0}] = {3}
k2[{0}] = {4}
k3[{0}] = {5}
k4[{0}] = {6}
dy[{0}] = {7}

""".format(i, x, y, k1, k2, k3, k4, dy, y+random.random()/1000))
i += 1