close all;
clear all;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%具体实例%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
a=-1;b=1;c=-1;d=1;
n=6;m=5;TOL=1e-10;
ITMAX=500;
%f=inline('x*exp(y)','x','y');
%ga=inline('0','x','y');gb=inline('2*exp(y)','x','y');
%gc=inline('x','x','y');gd=inline('exp(1)*x','x','y');
f=inline('2*pi^2*sin(pi*x)*sin(pi*y)','x','y');
ga=inline('0','x','y');gb=inline('0','x','y');
gc=inline('0','x','y');gd=inline('0','x','y');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%程序部分%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
h=(b-a)/n;
k=(d-c)/m;
x=linspace(a,b,n+1);
x=x(2:n);
y=linspace(c,d,m+1);
y=y(2:m);
u=zeros(n-1,m-1);
lmd=h^2/k^2;
mu=2*(1+lmd);
xx=[];
yy=[];
uu=[];
ture=[];
l=1;
while (l<=ITMAX)
z=(-h*h*f(x(1),y(m-1))+ga(a,y(m-1))+lmd*gd(x(1),d)+...
lmd*u(1,m-2)+u(2,m-1))/mu;
NORM=abs(z-u(1,m-1));
u(1,m-1)=z;
for i=2:n-2
z=(-h*h*f(x(i),y(m-1))+lmd*gd(x(i),d)+u(i-1,m-1)+...
u(i+1,m-1)+lmd*u(i,m-2))/mu;
if(abs(u(i,m-1)-z)>NORM)
NORM=abs(u(i,m-1)-z);
end
u(i,m-1)=z;
end
z=(-h*h*f(x(n-1),y(m-1))+gb(b,y(m-1))+...
lmd*gd(x(n-1),d)+u(n-2,m-1)+lmd*u(n-1,m-2))/mu;
if(abs(u(n-1,m-1)-z)>NORM)
NORM=abs(u(n-1,m-1)-z);
end
u(n-1,m-1)=z;
for j=m-2:-1:2
z=(-h*h*f(x(1),y(i))+ga(a,y(j))+lmd*u(1,j+1)+...
lmd*u(1,j-1)+u(2,j))/mu;
if(abs(u(1,j)-z)>NORM)
NORM=abs(u(1,j)-z);
end
u(1,j)=z;
for i=2:n-2
z=(-h*h*f(x(i),y(j))+u(i-1,j)+lmd*u(i,j+1)+...
u(i+1,j)+lmd*u(i,j-1))/mu;
if( abs(u(i,j)-z)>NORM)
NORM=abs(u(i,j)-z);
end
u(i,j)=z;
end
z=(-h*h*f(x(n-1),y(j))+gb(b,y(j))+u(n-2,j)+...
lmd*u(n-1,j+1)+lmd*u(n-1,j-1))/mu;
if(abs(u(n-1,j)-z)>NORM)
NORM=abs(u(n-1,j)-z);
end
u(n-1,j)=z;
end
z=(-h*h*f(x(1),y(1))+ga(a,y(1))+lmd*gc(x(1),c)+...
lmd*u(1,2)+u(2,1))/mu;
if(abs(u(1,1)-z)>NORM)
NORM=abs(u(1,1)-z);
end
u(1,1)=z;
for i=2:n-2
z=(-h*h*f(x(i),y(1))+lmd*gc(x(i),c)+...
u(i-1,1)+lmd*u(i,2)+u(i+1,1))/mu;
if(abs(u(i,1)-z)>NORM)
NORM=abs(u(i,1)-z);
end
u(i,1)=z;
end
z=(-h*h*f(x(n-1),y(1))+gb(b,y(1))+lmd*gc(x(n-1),c)+...
u(n-2,1)+lmd*u(n-1,2))/mu;
if(abs(u(n-1,1)-z)>NORM)
NORM=abs(u(n-1,1)-z);
end
u(n-1,1)=z;
if(NORM<=TOL)
for i=1:n-1
for j=1:m-1
xx=[xx,x(i)];
yy=[yy,y(j)];
uu=[uu,u(i,j)];
%tur(i,j)=x(i)*exp(y(j));
tur(i,j)=-sin(pi*x(i))*sin(pi*y(j));
ture=[ture,tur(i,j)];
end
end
break;
end
l=l+1;
end
re=[xx' yy' uu' ture']
%%%%%%%%%%%%%%%%%%%%%%%问题%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[Y,X]=meshgrid(y,x);
mesh(X,Y,u)
自学Matlab必备的60个小程序代码.rar （60个子文件） 
自学Matlab必备的60个小程序代码 
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