使用 JTransforms 的 FFT：它是基数 2 吗？

Question

I am using DoubleFFT_1D.realForward() from JTransforms in java to process a sample.

Does anyone know whether the length of the input double[] a to this method has to be a power of 2? Could not find the answer in the JTranforms documentation (might have missed it or perhaps I am not understanding correctly)

I tried with a sample having a random number of entries and it worked, but I'm just conscious whether it's doing it correctly or not and want to make sure that the method is indeed designed for any number of entries.

Thank you

Answer 1

Looking at the test code of DoubleFFT_1D::realForward() , it will also accept input array of lengths other than power of 2:

final double[] actual = new double[2 * n];
final double[] expected = new double[2 * n];
// ...
if (!CommonUtils.isPowerOf2(n)) {
// ...