CODEWITHSUNDEEP
matlabmatlab-coder
Zhenjie Zhao
Zhenjie Zhao

Reputation: 382

Matlab code generation of resample: the number of terms N must be constant

I use Matlab coder to generate C code of the following function:

function [out] = myresample(in)
    out = resample(in,4644,1000,10);
end

and generate the code by codegen myresample -args {coder.typeof(0, [1 Inf]), 0} -config cfg, where cfg = coder.config('lib'), cfg.DynamicMemoryAllocation = 'AllVariableSizeArrays'.

But it reports the error as:

??? The number of terms N must be constant.

I am confused why it is wrong. Interestingly, when I change the function to 

function [out] = myresample(in)
    out = resample(in,10,10,10);
end

it works.

I have found some links explaining how to generate code of resample. But it seems not work for my case.

I use Matlab 2017b.

Thanks.

Upvotes: 2

Views: 330

Answers (1)

alpereira7
alpereira7

Reputation: 1550

According to Matlab 2017b documentation:

C/C++ Code Generation: Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
C and C++ code generation for resample requires DSP System Toolbox™ software. The upsampling and downsampling factors must be specified as constants. Expressions or variables are allowed if their values do not change.
Variable-size inputs are not supported.

Here on your code, you have in that is not limited in size.

in your function myresample, you should try to specify a limitation. Something like:

limited_in = in(1:128);
out = resample(limited_in,4644,1000,10);

So the size of the inputs of resample will always be constant.

Upvotes: 1

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