С++ OpenCV - cv::dft - Without computing negative frequency terms

If I execute the following code:

    std::vector<std::complex<double>> inArr { 0, 0, 0, 1, 0 };
    std::vector<std::complex<double>> outArr;
    cv::dft(inArr, outArr);

Then the outArr array will contain:

[ 
  1.+0.j,
 -0.80901699+0.58778525i,
  0.30901699-0.95105652i,
  0.30901699+0.95105652i,
 -0.80901699-0.58778525i
]

Although I need a result without calculating negative frequency terms, i.e. such:

[ 
 1.+0.j,
-0.80901699+0.58778525i,
 0.30901699-0.95105652i
]

How can I do this ?

P.S. numpy.fft.rfft() works similarly in python.