Allow arbitrarily sized inputs for codegen without infinite bounds on array size

Hello, I am playing with the code generator (R2014b) and I am trying to allow an input to be an arbitrarily sized array with a fixed number of dimensions. This code (designed to allow me to test the speed of a random loop) seems to work:

function outVal = myFuncTest(inVal) %#codegen

assert(isa(inVal,'double'));
assert(all(size(inVal) <= [inf inf]));

outVal = zeros(100,1);
for ii = 1:100
    for jj = 1:numel(inVal)
        outVal(ii) = 3.*myFunc(inVal(jj)).*(ii./100);
    end
end

end

function outVal = myFunc(x)

outVal = (x.^2)/2;

end
end

The key to make it work seems to be this line:

 assert(all(size(inVal) <= [inf inf]));

but it doesn't seem right to me to have to use infs as an upper limit to array size. I have tried to use the coder.varsize option by putting:

coder.varsize('inVal',[]);

as the first line of the function instead, but when I do, I get an error saying that:

??? Size of inVal cannot be modified as the variable inVal is already locked.
Dimension 1 cannot be made dynamic: it has previously been set to have fixed size 1.

If I leave out both statements, the code compiles but then gives an error at runtime, since the coder seems to explicitly need variable size to be given:

myFuncTest_mex(ones(100))
MATLAB expression 'inVal' is not of the correct size: expected [1x1] found [100x100].

I would be grateful if someone could point out to me the correct way of achieving this, or let me know if there is any practical problem with using the infinite bounds on variable size.

Answer 1

[Ryan Livingston]

Using Inf is the standard way to specify unbounded array sizes for Coder. You can use that with assert or with varsize: coder.varsize('inVal',[Inf,Inf]);

[SE]

Great! Thanks for getting back to me on this.