import popen2
from math import  *

def F(x,y):
	return pow(x,2) - pow(y,2);

pi = 4*atan(1);

def cria_dados():
	x,y, z, t, delta = 0,0,0,0,0.01;
	dados = open("dados", "w");
	while(t < 2*pi):
		x = cos(t); y = sin(t);z = F(x,y);
		texto = str(x)+" "+ str(y)+" "+ str(z)+"\n";
		dados.write(texto);
		t += delta; ## t = t + delta 
	dados.close();


def cria_transfere(): 
	transfere = open("transfere", "w");
	transfere.write("pow(x,n) = x**n;  \n");
	transfere.write( "F(x,y) = pow(x,2) - pow(y,2);  \n");
	transfere.write( "splot \"dados\", F(x,y); \n");
	transfere.write( "pause -2 \"Aperte enter pra terminar\"; \n");
	transfere.close(); 

cria_dados();
cria_transfere();
popen2.popen3("gnuplot transfere");