Making Matlab throw an error on index out of bounds

I'm curious if it's possible to force Matlab to throw an error when an an array with predefined size is indexed out of bounds. For example, I'd like the following code to throw an error instead of simply making "i" 11 elements long:

function i = test()
%#codegen
i=zeros(10,1);

for j=1:11
        i(j) = 1;
end

end

Answer 1

[Matt J]

A subsref (right hand side indexing) operation will always throw an error if you index out of bounds. So, you could just insert one,

 for j=1:11

        discard=i(j); %will throw error if out of bounds.
        i(j) = 1;
 end

[dpb]

Actually, the's undoubtedly less overhead than the assert route...good thinking! :)

[Matt J]

Depends how big the index array is though. If it's just a scalar, no big deal. but if instead of j, you had a 100x100 array of indices J, the subsref will allocate 100x100 memory for i(J) and you will have serious overhead.

Answer 2

[dpb]

AFAIK, automagic reallocation is built in so deeply there's no way to avoid it. Best you can do is sotoo

assert(j>length(i), 'Array bound exceeded.')

in the loop before the access. This is bound to have highly detrimental effect on run time (as does bounds checking in compiled languages as well when turned on).

Answer 3

[David]

Thanks guys, sounds like there's no magic bullet :(