numsum(numsum(...)), how it works?

this is some of code lines

kin=zeros(12960,1);
for k=1:12960
kin(k)=numsum(numsum(unew(1:end,:).*unew(1:end,:)+vnew(1:end,:).*vnew(1:end,:)));

I know it is not correct, the unew and vnew are 100*100 (dimensions) How can i write in in a right way?

[Steven Lord]

What is "numsum"? There's no function by that name in any MathWorks toolboxes, and a search for that on mathworks.com found exactly one hit, this question.