06 October 2025 11:03:01 AM

FFT_SERIAL
  C++ version

  Demonstrate an implementation of the Fast Fourier Transform
  of a complex data vector.

  Accuracy check:

    FFT ( FFT ( X(1:N) ) ) == N * X(1:N)

             N      NITS    Error         Time          Time/Call     MFLOPS

             2     10000   7.85908e-17      0.000932      4.66e-08       214.592
             4     10000   1.20984e-16      0.002307    1.1535e-07       346.771
             8     10000    6.8208e-17      0.004232     2.116e-07       567.108
            16     10000   1.43867e-16       0.01001     5.005e-07       639.361
            32      1000   1.33121e-16       0.00206      1.03e-06       776.699
            64      1000   1.77654e-16      0.005103    2.5515e-06       752.499
           128      1000   1.92904e-16      0.010791    5.3955e-06       830.322
           256      1000   2.09232e-16      0.022734    1.1367e-05       900.853
           512       100   1.92749e-16      0.004743    2.3715e-05       971.537
          1024       100   2.31209e-16      0.011114     5.557e-05        921.36
          2048       100   2.44501e-16      0.023318    0.00011659       966.121
          4096       100   2.47659e-16      0.053145   0.000265725       924.866
          8192        10   2.57125e-16      0.011302     0.0005651       942.276
         16384        10    2.7363e-16      0.025417    0.00127085       902.451
         32768        10   2.92413e-16      0.051765    0.00258825       949.522
         65536        10   2.83355e-16      0.113282     0.0056641       925.633
        131072         1   3.14231e-16      0.024283     0.0121415       917.607
        262144         1     3.216e-16      0.053198      0.026599       886.987
        524288         1   3.28266e-16      0.109832      0.054916       906.974
       1048576         1   3.28448e-16      0.242463      0.121231       864.937

FFT_SERIAL:
  Normal end of execution.

06 October 2025 11:03:03 AM