clear all;close all;clc;

t = 0.03;       %时间范围，计算到0.03秒
x = 1;y = 1;    %空间范围，0-1米
m = 320;        %时间t方向分320个格子
n = 32;         %空间x方向分32个格子
k = 32;         %空间y方向分32个格子
ht = t/(m-1);   %时间步长dt
hx = x/(n-1);   %空间步长dx
hy = y/(k-1);   %空间步长dy

u = zeros(m,n,k);

%设置边界
[x,y] = meshgrid(0:hx:1,0:hy:1);
u(1,:,:) = sin(4*pi*x)+cos(4*pi*y);

%按照公式进行差分
for ii=1:m-1
    for jj=2:n-1
        for kk=2:k-1
            u(ii+1,jj,kk) = ht*(u(ii,jj+1,kk)+u(ii,jj-1,kk)-2*u(ii,jj,kk))/hx^2 + ...
                ht*(u(ii,jj,kk+1)+u(ii,jj,kk-1)-2*u(ii,jj,kk))/hy^2 + u(ii,jj,kk);
        end
    end
end

for i=1:200
    figure(1);
    mesh(x,y,reshape(u(i,:,:),[n k]));
    axis([0 1 0 1 -2 2]);
    
%     F=getframe(gcf);
%     I=frame2im(F);
%     [I,map]=rgb2ind(I,256); 
%     if i == 1
%         imwrite(I,map,\'test.gif\',\'gif\',\'Loopcount\',inf,\'DelayTime\',0.05);
%     else
%         imwrite(I,map,\'test.gif\',\'gif\',\'WriteMode\',\'append\',\'DelayTime\',0.05);    
%     end
end