Language Model (LM): We train a two layer recurrent neural language model with GRU cells of hidden size 512.

 Sequence-to-Sequence Attention Model (S2S): We train a two layer neural sequence to sequence model equipped with bi-linear attention function with GRU cells of hidden size 512.  Linear Dynamical System (LDS): We also train a linear dynamical system as discussed in Section SECREF1 as one of our baselines for fair comparisons. Semi-Supervised SLDS (SLDS-X%): To gauge the usability of semi-supervision, we also train semi-supervised SLDS models with varying amount of labelled sentiment tags unlike the original model which uses 100% tagged data.  
 Question: What baselines are used?
a two layer recurrent neural language model with GRU cells of hidden size 512 a two layer neural sequence to sequence model equipped with bi-linear attention function with GRU cells of hidden size 512 a linear dynamical system semi-supervised SLDS models with varying amount of labelled sentiment tags