Table 1: Computation times (s).

Direct COCG COCR COCG-FFT COCR-FFT
#dipoles MATLAB C++ (Armadillo) MATLAB C++ (Armadillo) MATLAB C++ (Armadillo) MATLAB C++ MATLAB C++
Armadillo FFTW Armadillo FFTW

441 0.0045 0.05400.00290.0033 0.0034 0.0037 0.0413 0.0029 0.0069 0.04123 0.0030 0.0069
1681 0.1790 2.1660 0.0790 0.0632 0.0830 0.0680 0.1869 0.0565 0.0600 0.1851 0.0589 0.0549
6561 5.3340 57.8030 1.5296 1.4693 1.6020 1.5353 1.4603 1.2336 0.6431 1.4410 1.3612 0.6512