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by fchollet 4153 days ago
> One layer Autoencoder - SVD done by a neural network

Not necessarily. Any serious user of autoencoders would apply some kind of L1 regularization or other sparsity constraint to the coefficients learned, so that the autoencoder does not learn the principal components of the data but instead learns an analogous sparse decomposition of the data (with the assumption that sparse representations have better generalization power).

Also I don't think any of the techniques you mentioned is being passed as "not SVD" by its practitioners. People know they're SVD. These names are just used as labels for use cases of SVD, each with their specific (and crucial) bells and whistles. And yes, these labels are useful.

Cognition is fundamentally dimensionality reduction over a space of information, so clearly most ML algorithms are going to be isomorphic to SVD in some way. More interesting to me are the really non-obvious ways in which that is happening (eg. RNNs learning word embeddings with skip-gram are actually factorizing a matrix of pairwise mutual information of words over a local context...)

That doesn't make these algorithms any less valuable.

1 comments

I'd also add here that you can add other variables in to the mix such as gaussian noise and drop out which is the basis for a lot of fundamental neural networks. I get the intent, but it's not necessarily the case.

Neural word embeddings are one of the most fun things I work with. Both word2vec as well as glove and paragraph vectors.

There's also the ability to learn varying length windows of phrases via recursive or convolutional methods.