Tfjs: Support tf.spectral.ifft, tf.spectral.rfft and tf.spectral.irfft

[nsthorat]

Currently we only support tf.spectral.fft(), we should support tf.spectral.ifft, tf.spectral.rfft and tf.spectral.irfft.

[nsthorat]

cc @Lewuathe

[Lewuathe]

As long as I understand correctly, rfft is just a subset of fft, while the other two may need separated implementation.

Anyway, I'm going to work on this.

[nsthorat]

Awesome @Lewuathe! BTW, we should fix this first (so it works for all the other ops too): https://github.com/tensorflow/tfjs/issues/781

[Lewuathe]

That makes sense. I'll take a look.

[nsthorat]

I'm going to knock these off since there's a Google team that wants these ops soon :)

[Lewuathe]

@nsthorat Are you working on tf.spectral.rfft and tf.spectral.irfft too?

[nsthorat]

@Lewuathe I haven't started yet! If you want to take this, go ahead if you think it will be in the near term future :) Note that this is not exactly the same as real(fft(x)).

[nsthorat]

This is done.

[faroit]

@nsthorat great news. Does this mean I could expect signal.inverse_stft to work on tfjs?

[nsthorat]

These ops aren't supported yet (just the ones listed on this issue).

I filed a new issue for those ops: https://github.com/tensorflow/tfjs/issues/1362