编程的时候遇到这种问题怎么解决啊
Error using ==> diag
Out of memory. Type HELP MEMORY for your options.
这是我编的负二项的COOK距离程序：

data;

x1=ones(27326,1); x2=data(:,2);x3=data(:,3);x4=data(:,4);

y=data(:,1); x= [x1,x2,x3,x4];[n,d]=size(x);

a=1.936348; b=[0.9132608,0.0204292, -0.4768144,-0.0459575]';

   u=exp(x*b);

laa=sum(a^(-4).*(psi(1,y+1/a)-psi(1,1/a))+2/a^3.*(psi(y+1/a)-psi(1/a)-log(a.*u+1))+(3*a*u.^2+2*u-y-2*a*y.*u)./(a+a^2)^2);

lab= x'*((u.^2-u.*y)./(1+a*u).^2);

lbb=x'*diag((-u-a*u.*y)./(1+a.*u).^2)*x;

I1=[lbb lab;lab' laa];

GD=[];

for i=1: 27326

xx= [x1(i),x2(i),x3(i),x4(i)];

la=1/a^2*(psi(1/a)-psi(y(i)+1/a)+log(1+a*u(i)))+(y(i)-u(i)) /(a+a^2*u(i));

lb=((y(i)-u(i))/(1+a*u(i))).*xx';

GD(i)=[lb;la]'*inv(-I1)*[lb;la];

GDa(i)=la*inv(laa)*la;

GDb(i)=lb'*inv(-lbb)*lb;

end
plot(GD)