MATLAB: Ho to use a dynamic array in a MEX file function

arrayMATLABmatlab codermexmex compilertransfer function

Hi I am using a C function in my MATLAB project and one of the inputs is a dynamic array, how can I modify this input since in build.m the inputs are set up and fixed. I want to be able to throw any array size in to it. Following you can find the files I am using:
bimi.c
#include "bimi.h"
extern void bimi(int* poly, int* polysz, int* output){
    int i;
    int a=*(polysz);
    for(i=0;i<a;i++){
        output[i]=2*poly[i];
    }
}
bimi.h
extern void bimi(int* poly, int* polysz, int* output);
bimifunc.m
function y = bimifunc(poly2, polysz2)  %#codegen
         y = coder.nullcopy(zeros(1,5,'int32'));
         coder.updateBuildInfo('addSourceFiles','bimi.c');
         fprintf('Running Custom C Code...\n\n');
         coder.ceval('bimi',coder.ref(poly2),coder.ref(polysz2), coder.ref(y));
end
build.m, this where the input size is setup and fixed, how can I make it dynamic?
function build(target)
    % Entry point function:
    entryPoint = 'bimifunc';%
      %Example input
      poly=zeros(1,5, 'int32');%THIS WHERE I WANT THE DYNAMIC ARRAY OR IS THERE ANOTHER WAY?
      polysz=int32(length(poly));*
      % Configuration object:
      cfg = coder.config(target);
      % Custom source files:
      cfg.CustomSource = 'bimi.c';
      cfg.CustomSourceCode = [ '#include "bimi.h"' ];
      % Generate and Launch Report:
      cfg.GenerateReport = true;
      cfg.LaunchReport = false;
      % Generate Code:
      codegen(entryPoint,'-args', {poly, polysz},'-config', cfg)
end
test.m, I want to be able to generate any random size of array and throw it to the function for calculations.
    %testing the c code embeded to matlab
    poly=ones(1,5, 'int32');
    polysz=int32(length(poly));
    chichi=bimifunc_mex(poly, polysz);

Best Answer

Update your code:
function y = bimifunc(poly2, polysz2)  %#codegen

%coder.updateBuildInfo('addSourceFiles','bm.c');

y = coder.nullcopy(zeros(1,polysz2,'int32'));
and the codegen command to use a variable size input:
codegen(entryPoint,'-args', {coder.typeof(poly,[1,Inf]), polysz},'-config', cfg)
That will make the input, poly a 1-by-:Inf array and allocate the output y based on the size of polysz.
Another suggestion would be rather than taking polysz as an argument to your MATLAB function, should it just be:
function y = bimifunc(poly2)  %#codegen
%coder.updateBuildInfo('addSourceFiles','bm.c');
polysz2 = int32(length(polysz2));
y = coder.nullcopy(zeros(1,polysz2,'int32'));
and then:
codegen(entryPoint,'-args', {coder.typeof(poly,[1,Inf])},'-config', cfg)
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