ISTFT

[jamarshon]

Inverse STFT

[vincentqb]

Thanks for working on this! Do you have a reference besides [1] that presents the implementation done here?

[jamarshon]

@vincentqb I think that [1] is sufficient to describe the overlap add method

[vincentqb]

@jamarshon Thanks for specifying the default values in the header of the function.

For acceptance, we need to validate correctness by documenting and testing enough to confirm the pull request is indeed correct. Evidences make the approval process faster.

For documentation, we need to provide references for the details of the implementation provided. For example, beside [Griffin and Lim], did you base your implementation on scipy's? The description of the pull request needs to offer enough context to understand the evidences provided: see for instance the new issue tab for pytorch. For instance, there are other issues or pull requests that are relevant, say #27 and #3775.

For testing,

1. we need to show important properties are fulfilled: for example, the composition of ISTFT and STFT (and of STFT and ISTFT) is the identity under appropriate conditions,
2. the algorithm is correct for a known analytical solution,
3. the algorithm matches the result of an outside implementation.

If for example scipy's implementation was used as a reference, it could be mentioned here along with a notebook showing that the two results are the same, see for instance #21250.

(For reference, here are general acceptance criteria here.)

[jamarshon]

for reference, stft tests are being added for #131

Implementation inspired by https://github.com/seungwonpark/istft-pytorch/blob/master/istft_deconv.py

[vincentqb]

Let's use sines as analytical solution. Could you try the following analytical solution? Take f(t) = sin(2*pi*n*t/L) where L is the window length and hop. The result should be a band at frequency 2*pi*n/L.

[vincentqb]

Based on the testing we have done, the PR looks good to me. Thanks for working on this!