Phased LSTM

Phased LSTM

Standard LSTM & Phased LSTM

Features	std lstm	PHASED LSTM
Sampling Rate	Synchronous	Asynchronous
Convergence	Slow	Fast
Computation	Large	Small
Performance	Low	High
Memory decay	Every time step	Only open period

Note: Information can flow pass Time Gate in both its open period and close period.

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Phased LSTM

Phased LSTM=Std LSTM+Time Gate

LSTM formula:

​ Phased LSTG , formula only (3) and (5) are changed:

Time Gate formula:

Variable	meaning
ct	cell activation vector
xt	input feature vector
ht	hidden output vector
σi,σf,σo	sigmoid
σc,σh	tanh

Inplementation

Phased LSTM implementation in Tensorflow:
https://github.com/Enny1991/PLSTM