Function test_random_ffts

dlib/test/fft.cpp:116–161

// ----------------------------------------------------------------------------------------
    
    void test_random_ffts()
    {
        int test = 0;  
        for (int nr = 1; nr <= 64; nr++)
        {
            for (int nc = 1; nc <= 64; nc++)
            {
                if (++test % 100 == 0)
                    print_spinner();

                const matrix<complex<double> > m1 = rand_complex<double>(nr,nc);
                const matrix<complex<float> > fm1 = rand_complex<float>(nr,nc);

                DLIB_TEST(max(norm(ifft(fft(m1))-m1)) < 1e-16);
                DLIB_TEST(max(norm(ifft(fft(fm1))-fm1)) < 1e-7);

                matrix<complex<double> > temp = m1;
                matrix<complex<float> > ftemp = fm1;
                fft_inplace(temp);
                fft_inplace(ftemp);
                DLIB_TEST(max(norm(temp-fft(m1))) < 1e-16);
                DLIB_TEST(max(norm(ftemp-fft(fm1))) < 1e-7);
                ifft_inplace(temp);
                ifft_inplace(ftemp);
                DLIB_TEST(max(norm(temp/temp.size()-m1)) < 1e-16);
                DLIB_TEST(max(norm(ftemp/ftemp.size()-fm1)) < 1e-7);
            }
        }

        {
            // test size 0 matrices.
            matrix<complex<double>> temp;
            matrix<complex<float>> ftemp;
            fft_inplace(temp);
            fft_inplace(ftemp);
            DLIB_TEST(temp.size() == 0);
            DLIB_TEST(ftemp.size() == 0);

            DLIB_TEST(fft(temp).size() == 0);
            DLIB_TEST(ifft(temp).size() == 0);

            matrix<double> rtemp;
            DLIB_TEST(fftr(rtemp).size() == 0);
            DLIB_TEST(ifftr(temp).size() == 0);
        }
    }

// ----------------------------------------------------------------------------------------