close all;clear all;clc;
vnow =zeros(30,30);
vprev=zeros(30,30);
vnow(30,:)=10;
error=max(max(abs(vnow - vprev)));
iter=0;
while error>0.1
for i=2:29
for j=2:29
vnow(i,j)=(vnow(i+1,j)+vnow(i-1,j)+vnow(i,j-1))/4;
endfor
endfor
error = max(max(abs(vnow-vprev)));
vprev=vnow;
iter=iter+1;
imagesc(vnow);colorbar;axis('xy');colormap('jet');
pause(0.01);
[ex,ey]=gradient(vnow,1);
ex=-ex;
ey=-ey;
ex=ex./sqrt(ex.^2+ey.^2);
ey=ey./sqrt(ex.^2+ey.^2);
hold('on');quiver(ex,ey,'k');
endwhile