RFFT_WithoutChecks(Span<System.Numerics.Complex> destination, Span<System.Numerics.Complex> input) only uses the length of the input parameter, and not the data inside. The ForwardReal method calling this method apparently isn't tested.

I am curious about the ForwardReal methods. Are they supposed to be identical in output to the corresponding numpy methods? I ask because the the numpy.fft.rfft method states "If the input a contains an imaginary part, it is silently discarded." Secondly, the purpose of rfft seems to be increased efficiency, because it uses a different algorithm to avoid calculating the portion thrown out.