I want change the matlab code to C code with MATLAB Coder!

i want to chage the mathlab code to C code with MATLAB coder

I want to solve the IDFT and DFT in C compiler but C compiler no apply complex in exp function.

so i use the MATLAB Coder first time

but I have little problem in Check for Run-Time Issues

function C=IDFT(x)

N=4;

x=[1 2 2 1];

n=0:N-1;

K=0:N-1;

WN=exp(-j*2*pi/N).^n;

for m=1:N

X(m)=sum(x.*WN.^(m-1));

end

df=1/500;

f=df*[0:500];

W=exp(-j*2*pi.*f);

xf=zeros(1,length(f));

for m=1:N

xf=xf+x(m)*W.^(m-1);

end

for m=1:N

x(m)=sum(X.*(WN.^(-1)).^(m-1))/N;

end

and MATLAB Coder return error

line NO 8 Variable 'X' has not been assigned. To assign the variable, use a complete assignment and not a subscript. Code generation does not support creating arrays via indexing.

line NO 15 Cannot assign a complex value into a non-complex location.

How can i do?

Answer 1

[Angelo Yeo]

Before using MATLAB Coder, there are a few things to check.

1. The input argument x is assigned internally in line 3. You should remove it.
2. What's the output of the function IFDT? There is no process to calculate C.
3. Also, why is x calculated at the end of the function? Wasn't x an input for your function?
4. What is k in line 5 for?

Regarding the error you encountered, any variables must be explicitly assigned with its type and size when you translate M file into C/C++. This is because C language is not as dynamic as MATLAB. See how to make MATLAB code suitable for C/C++ code generation in the doc below.

Generate C Code by Using the MATLAB Coder App