I compiled a simple function with matlab coder. The function takes three input arguments: xvec is [nx,1], yvec is [ny,1] and zmat is [nx,ny]. All is good the first time I run the mex function, but if I subsequently change the size of one of the input arrays (say I change nx from nx=8 to nx=7), the function crashes. Of course I can compile again the code and it runs, but I really want to avoid recompilation every time I change the dimension of the inputs!
MWE here:
clear
clc
close all
nx = 8;
ny = 3;
xvec = linspace(0,1,nx)’;
yvec = linspace(0,1,ny)’;
zmat = xvec.^2+yvec’; % [nx,ny]
%size(zmat)
disp(‘Calling myfun…’)
res = myfun(xvec,yvec,zmat);
% MEX with codegen
disp(‘Compiling MEX…’)
cfg = coder.config(‘mex’);
cfg.GenerateReport = true;
codegen -config cfg myfun -args {xvec,yvec,zmat} -o myfun_mex
disp(‘Calling myfun_mex…’)
res_mex = myfun_mex(xvec,yvec,zmat);
err_mex = abs(res-res_mex)
and here is the function:
function res = myfun(x,y,z)
res = sum(x)+sum(y)+sum(sum(z));
end
First time, I compile and it runs OK. Then, if I set nx=7, it crashes with the following error message:
“`
Incorrect size for expression ‘x’: expected [8×1] but found [7×1].
Error in myfun_mex
Error in main (line 22)
res_mex = myfun_mex(xvec,yvec,zmat);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
“`
Any help is greatly appreciated, thanks!I compiled a simple function with matlab coder. The function takes three input arguments: xvec is [nx,1], yvec is [ny,1] and zmat is [nx,ny]. All is good the first time I run the mex function, but if I subsequently change the size of one of the input arrays (say I change nx from nx=8 to nx=7), the function crashes. Of course I can compile again the code and it runs, but I really want to avoid recompilation every time I change the dimension of the inputs!
MWE here:
clear
clc
close all
nx = 8;
ny = 3;
xvec = linspace(0,1,nx)’;
yvec = linspace(0,1,ny)’;
zmat = xvec.^2+yvec’; % [nx,ny]
%size(zmat)
disp(‘Calling myfun…’)
res = myfun(xvec,yvec,zmat);
% MEX with codegen
disp(‘Compiling MEX…’)
cfg = coder.config(‘mex’);
cfg.GenerateReport = true;
codegen -config cfg myfun -args {xvec,yvec,zmat} -o myfun_mex
disp(‘Calling myfun_mex…’)
res_mex = myfun_mex(xvec,yvec,zmat);
err_mex = abs(res-res_mex)
and here is the function:
function res = myfun(x,y,z)
res = sum(x)+sum(y)+sum(sum(z));
end
First time, I compile and it runs OK. Then, if I set nx=7, it crashes with the following error message:
“`
Incorrect size for expression ‘x’: expected [8×1] but found [7×1].
Error in myfun_mex
Error in main (line 22)
res_mex = myfun_mex(xvec,yvec,zmat);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
“`
Any help is greatly appreciated, thanks! I compiled a simple function with matlab coder. The function takes three input arguments: xvec is [nx,1], yvec is [ny,1] and zmat is [nx,ny]. All is good the first time I run the mex function, but if I subsequently change the size of one of the input arrays (say I change nx from nx=8 to nx=7), the function crashes. Of course I can compile again the code and it runs, but I really want to avoid recompilation every time I change the dimension of the inputs!
MWE here:
clear
clc
close all
nx = 8;
ny = 3;
xvec = linspace(0,1,nx)’;
yvec = linspace(0,1,ny)’;
zmat = xvec.^2+yvec’; % [nx,ny]
%size(zmat)
disp(‘Calling myfun…’)
res = myfun(xvec,yvec,zmat);
% MEX with codegen
disp(‘Compiling MEX…’)
cfg = coder.config(‘mex’);
cfg.GenerateReport = true;
codegen -config cfg myfun -args {xvec,yvec,zmat} -o myfun_mex
disp(‘Calling myfun_mex…’)
res_mex = myfun_mex(xvec,yvec,zmat);
err_mex = abs(res-res_mex)
and here is the function:
function res = myfun(x,y,z)
res = sum(x)+sum(y)+sum(sum(z));
end
First time, I compile and it runs OK. Then, if I set nx=7, it crashes with the following error message:
“`
Incorrect size for expression ‘x’: expected [8×1] but found [7×1].
Error in myfun_mex
Error in main (line 22)
res_mex = myfun_mex(xvec,yvec,zmat);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
“`
Any help is greatly appreciated, thanks! codegen, function, mex MATLAB Answers — New Questions

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