from numpy import*
from Tkinter import *
import time

dt = 0.1
dx = 1
D = 1
alpha = D*dt/dx**2
nodes = 500
source_node = nodes/2

x = arange(0, nodes, 1)
u_new = zeros(nodes)
u = zeros(nodes)

##--Tkinter stuff--
t_start = time.time()#for referencing
height = 300.0
width = 400.0
center = height//2
x_factor = width/(nodes-1)
y_factor = 400
##------------------
u[source_node] = 1
	
def paint(canvas, parent):
	for i in range (1, nodes-1):
		u_new[i] = u[i] + alpha*(u[i+1]-2.0*u[i]+u[i-1])
	for i in range (0, nodes):
		u[i] = u_new[i]	
	##--Tkinter stuff--
	xy = []
	for i in range(0, nodes):
		xy.append((int)(i*x_factor))
		xy.append((int)(u_new[i]*y_factor)+center)
	#time.sleep(0.001)	
	c.coords("curve", *xy)
	parent.after_idle(paint,parent,canvas)
	##------------------	
#--Tkinter stuff:--
root = Tk()
root.title("Animated solution to 1D diffusion equation")
root.bind('q','exit')
c = Canvas(width=width, height=height, bg='white')
c.pack()
c.create_line(tag = "curve", *zeros(2*width), fill='blue')	
root.after(100,paint,root,c)
root.mainloop()	
##------------------