GitLab

- Renamed torchaudio.functional.create_fb_matrix to torchaudio.functional.melscale_fbanks.
- Added interface with a warning for create_fb_matrix

* Pin MKL to 2021.2.0

Fixes https://github.com/pytorch/pytorch/issues/62424

* Apply the same  constraint for conda builds

Use less-than-equals constraint to avoid dependency conflicts for
python-3.6 environment

Summary:
- Add linear_fbank method
- Add LFCC in transforms

Rebases #1571; addresses #1569:

"In 0.9.0 we are deprecating the lazy behavior of MelScale because it can make an invalid 
TorchScript object and it does not align with the design of torchaudio. Now in master 
branch, we can remove the implementation."
Co-authored-by: Pankaj Patil <pankaj.patil2099@hotmail.com>
Co-authored-by: moto <855818+mthrok@users.noreply.github.com>
Co-authored-by: hwangjeff <jeffhwang@fb.com>

Porting Tacotron2 from https://github.com/NVIDIA/DeepLearningExamples/blob/master/PyTorch/SpeechSynthesis/Tacotron2/tacotron2/model.py

`torchaudio._internal.fft` was originally added to account for the introduction of module `torch.fft`, when `torch.fft` could refer to either a module or function. Now that `torch.fft` refers unambiguously to a module, we remove `torchaudio._internal.fft` and replace references to it with `torch.fft`.