```
function [Y,M] = resynth_nmf(X, W, H, I)
% [Y,M] = resynth_nmf(X, W, H, I)
% Resynthesize audio from NMF decomposition.
% X is the original STFT; W and H are the NMF model;
% I is the index of a subset of the NMF dimensions.
% Y returns the resynthesized audio;
% M returns the actual STFT-domain mask that was applied
% 2013-04-29 Dan Ellis dpwe@ee.columbia.edu
% Scale original STFT by ratio of partial NMF reconstruction to whole thing
M = (W(:,I)*H(I,:)) ./ (W*H);
Y = istft(X .* M);
```