Python - Google Colab - IndexError: index 2 is out of bounds for axis 0 with size 1

I am trying to solve the sparse matrix equation

u_derivative_1 = A * u 

(A is the sparse matrix)

But I'm getting the following error :-

  IndexError                                Traceback (most recent call last)<ipython-input-24-f4af80e4ae52> in <cell line: 1>()  ----> 1 trial1 = discretise_delta_u_v4(1000, 'implicit')<ipython-input-23-731d13e4ddf7> in discretise_delta_u_v4(N, method)       61         for i in range (1 , N-1):       62           for j in range (1 , N-1):  ---> 63             A[i,j] = (u[i-1,j] + u[i+1,j] + u[i,j-1] + u[i,j+1] - (4*u[i,j]))/(h**2)       64   IndexError: index 2 is out of bounds for axis 0 with size 1

I am confused why I am getting this error and how to resolve this. This is my code -

import numpy as npimport scipyimport scipy.sparsefrom scipy.sparse import csr_matrixfrom scipy.sparse import coo_matrixdef discretise_delta_u_v4(N, method):    i = np.arange(0,N)    j = np.arange(0,N)    h = 2/N    A = csr_matrix((N, N), dtype = np.float64).toarray()    u = np.array([[(i*h), (j*h)]])    #u[ih,jh] =     u[:,0] = 5    #Boundary    u[:,-1] = 0   #Boundary    u[0,:] = 0    #Boundary    u[-1,:] = 0   #Boundary    #Implicit    if (method=='implicit') :        A[0,:] = 0        A[-1,:] = 0        A[:,0] = 0        A[:,-1] = 0        for i in range (1 , N-1):          for j in range (1 , N-1):            A[i,j] = (u[i-1,j] + u[i+1,j] + u[i,j-1] + u[i,j+1] - (4*u[i,j]))/(h**2)    # u_der_1 = A * u    for i in range (0 , N):      for j in range (0 , N):        u_der_1 = scipy.sparse.linalg.spsolve(A,u)trial1 = discretise_delta_u_v4(1000, 'implicit')