MATLAB program to compute the potential in a square region by solving Laplace’s equation using the Finite Difference (FD) approximation method.using the “surf” and “contour” MATLAB commands

My Code:

clear all;
[X,Y] = meshgrid(linspace(0,1,20));
V = zeros(size(X));
[M,N] = size(V);

V(2:M-1,1) = zeros(M-2,1);
V(2:M-1,N) = 100;

V(1,2:N-1) = 40;
V(M,2:N-1) = 10;

for r = 1:10000
    V(2:M-1,2:N-1) = 0.25*(V(3:M,2:N-1) + V(1:M-2,2:N-1) + V(2:M-1,2:N-1) + V(4:M-1,2:N-1));
end

surf(X,Y,V);

Getting Error:

>> contour(X,Y,V)

Unrecognized function or variable 'X'.

[Sai Hitesh Gorantla]

please respond

Answer 1

[KSSV]

Just rectifies the error you said:

clc; clear all ;
clear all;
[X,Y] = meshgrid(linspace(0,1,20));
V = zeros(size(X));
[M,N] = size(V);

V(2:M-1,1) = zeros(M-2,1);
V(2:M-1,N) = 100;

V(1,2:N-1) = 40;
V(M,2:N-1) = 10;

for r = 1:10000
    V(2:M-1,2:N-1) = 0.25*(V(3:M,2:N-1) + V(1:M-2,2:N-1) ....
                     + V(2:M-1,2:N-1) + V(2:M-1,2:N-1));
end

surf(X,Y,V);

[Sai Hitesh Gorantla]

I'm not getting the expected output.

for contour

[Sai Hitesh Gorantla]

[KSSV]

I have already mentioned it rectifies onl the error. For expected contour, you have to check your code according to the theory or formula.