求教，关于Improper assignment with rectangular empty matrix的问题
 

运行以下程序发现[COLOR="Red"]Improper assignment with rectangular empty matrix[/COLOR]错误，请大家帮忙解决
A=[1 -3 3;3 -5 3;6 -6 4];
B=eig(A);
B=eig(A);
C=sort(B,'descend');
MIN_NUM=-99;
D=zeros([3 3]);
for i=1:3
temp=C(i);
D(:,i)=null(A+temp*eye(length(A)));
C(i)=MIN_NUM;
end