Suppose we are doing sentiment analysis for a restaurant. Customers can rate the restaurant by #1: how expensive the restaurant is, #2:how good is the food and #3: how likely they will come again. The ratings are dependent,i.e. the more expensive the restaurant is (higher #1), the less likely they will come back (lower #3), but whey will if the food is good (higher #2).
My questions are: is there a good RNN structure(review as input, #1-#3 as output) that can capture and model the dependency among #1 – #3? Specifically, how many RNN cells should be used to take care of the unequal lengths of user reviews?