cranck nicholson stuck on BCs

gistfile1.txt

from numpy import *
from matplotlib.pyplot import *

from time import sleep

import numpy as np
import networkx as nx

dim = [3,2]

dt = 1  #time step


G = nx.generators.classic.grid_graph(dim, periodic=False, create_using=None)

L = nx.laplacian(G)

#print L.shape[0]          #gets the length of the zeroth entry of the laplacian

n = L.shape[0]

tup = 100
tlow = 0
dt = .5
nt = (tup-tlow)/dt

T = 60*ones( (n,tup) )		#setting initial temperature
for i in range(n/2):
	T[i,0] = 0;

i=0
W = ones( (n,n) ) + dt/2*L
print W
print dt
#for i in range(t):
for i in range(2):
	
	
	 
	T[:,i+2] = dot(linalg.inv( ones( (n,n) ) + dt/2*L )*(ones( (n,n) ) - dt/2*L),T[:,i+1])	#note dot(a,v) treats v as a column
																					#vector while dot(v,a) treats v like
#print T