exm041523_1.m

好多m文件

n=5;SM1=sparse(1:n,1:n,-2*ones(1,n),n,n,n);
SM2=sparse(2:n,1:n-1,ones(1,n-1),n,n,n-1);S1=SM1+SM2+SM2'
e=ones(n,1);S2=spdiags([e,-2*e,e],[-1,0,1],n,n),SF=full(S1)