CODEWITHSUNDEEP
c++cmatlabmex
Rolaro
Rolaro

Reputation: 1

Return Double Complex Array in MEX file (Matlab)

I have a problem with MEX files in C/C++ coding. I need to return a double complex array to Matlab but I am not able to do that and I don't find information about it. I show my code with some tries:

double complex output[nSymb];
nlhs = 1;
plhs[0] = mxCreateDoubleMatrix(nSymb,(mwSize)nlhs,mxCOMPLEX);

// 1º option
plhs[0] = output;
// 2º option
memcpy(plhs, output, nSymb * sizeof(double complex));
// 3º option
plhs = output;

Thanks you in advance.

Upvotes: 0

Views: 732

Answers (1)

Mansoor
Mansoor

Reputation: 2438

You mentioned C++, so I've shown an example copying a std::vector<double> into an MxArray object, same can be applied to C-style arrays:

mxArray* CreateDoubleArray(const std::vector<double>& d)
{
    mxArray* m = mxCreateDoubleMatrix(d.size(), 1, mxComplexity::mxReal); // mxComplexity::mxCOMPLEX 
    double* pm = mxGetDoubles (m); // mxGetComplexDoubles
    
    for (size_t i=0; i<d.size(); i++)
    {
        pm[i] = d[i];
    }
    
    return m;
}

// ...
// Return value for the Mex:
plhs[0] = CreateDoubleArray(stdVecObj);

You can change the value_type of the vector to std::complex, and apply the changes suggested in the comments to handle complex type instead of double. mxGetComplexDoubles returns a MxDOUBLE_CLASS* documented here (it's just a struct with a real and imaginary component of type mxDouble).

Upvotes: 1

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