Embeded MATLAB function variable-size signal

Hello all

I am simulating something on simulink that requires me to take some number as an input then

generate variable size output signal.

For example, say I have input that says 2, 14, 10.

I am supposed to create [1 by 2] vector then, [1 by 14] vector then, [1 by 10] and so on..

I know that my output variable will not exceed [1 by 10000], so I was trying to define inside function just to see if it works:

function y = fcn(u) %#codegen coder.varsize('y', [1 10000]); y = zeros(u, 1);

I also went to simulink->Edit Data then check my variable y to be variable size and I specified [1 10000], but

still it gives me an error saying:

Computed maximum size is not bounded. Static memory allocation requires all sizes to be bounded. The computed size is [:1 x ?].

Answer 1

[Ryan Livingston]

You can add calls to ASSERT which effectively bounds the values arguments:

 function y = fcn(u)
 %#codegen
 N = 10000;
 coder.varsize('y', [1 N]);
 assert(u < N);
 y = zeros(1, u);

should do the trick.

The error is effectively complaining about computing the size for the expression:

 zeros(1, u);

Which, provided the information given it must assume is unbounded.

You can reference:

http://www.mathworks.com/help/simulink/ug/variable-size-data-when-dynamic-memory-allocation-is-disabled.html#br9t1u3

for more documentation on this approach.

[mettala]

I have somewhat similar problem as Daniel had 2 years ago. I tried to use your function with constant input of 14 (or any other value) and get the following error message:

The signal at output port 2 of 'XXX' is a variable-size signal with a nondiscrete sample time.
The sample time for any variable-size signal must be discrete.

I have changed the output to variable and size is specified [1 10000].