Warning: Input arguments must be scalar.出什么错了？

[yuyilin0507]

Warning: Input arguments must be scalar.
> In Schmidt at 5

程序如下，方阵Schmidt正交化。
function Q=Schmidt(A)
n=size(A);
P(:,1)=A(:,1);
for j=2:n
lamda=zeros(n,1);
for k=1:j-1
lamda=lamda+(P(:,k)'*A(:,j))/(P(:,k)'*P(:,k))*P(:,k);
end
P(:,j)=A(:,j)-lamda;
end
for i=1:n
Q(:,i)=P(:,i)/abs(sqrt(P(:,i)'*P(:,i)));
end