<p>It depends on the usage:</p>

<p>1) If you only want to get sentence vector for some known data. Check out  paragraph vector in these papers:</p>

<p>Quoc V. Le and Tomas Mikolov. 2014. Distributed representations of sentences and documents. Eprint Arxiv,4:1188–1196. </p>

<p>A. M. Dai, C. Olah, and Q. V. Le. 2015. DocumentEmbedding with Paragraph Vectors. ArXiv e-prints,July.</p>

<p>2) If you want a model to estimate sentence vector for unknown(test) sentences with unsupervised approach:</p>

<p>You could check out this paper:</p>

<p><a href="https://github.com/StevenLOL/aicyber_semeval_2016_ivector" rel="noreferrer">Steven Du and Xi Zhang. 2016. Aicyber at SemEval-2016 Task 4: i-vector based sentence representation. In Proceedings of the 10th International Workshop on Semantic Evaluation (SemEval 2016), San Diego, US</a></p>

<p>3)Researcher are also looking for the output of certain layer in RNN or LSTM network, recent example is:</p>

<p><a href="http://www.aaai.org/ocs/index.php/AAAI/AAAI16/paper/view/12195" rel="noreferrer">http://www.aaai.org/ocs/index.php/AAAI/AAAI16/paper/view/12195</a></p>

<p>4)For the gensim doc2vec, many researchers could not get good results, to overcome this problem, following paper using doc2vec based on pre-trained word vectors.</p>

<p><a href="https://github.com/jhlau/doc2vec" rel="noreferrer">Jey Han Lau and Timothy Baldwin (2016). An Empirical Evaluation of doc2vec with Practical Insights into Document Embedding Generation. In Proceedings of the 1st Workshop on Representation Learning for NLP, 2016.</a></p>

<p>5) <a href="https://github.com/search?utf8=%E2%9C%93&amp;q=tweet2vec&amp;type=" rel="noreferrer">tweet2vec</a> or <a href="https://github.com/epfml/sent2vec" rel="noreferrer">sent2vec</a>
.</p>

<p>Facebook has SentEval project for evaluating the quality of sentence vectors. </p>

<p><a href="https://github.com/facebookresearch/SentEval" rel="noreferrer">https://github.com/facebookresearch/SentEval</a></p>

<p>6) There are more information in the following paper:</p>

<p>Neural Network Models for Paraphrase Identification, Semantic Textual Similarity, Natural Language Inference, and Question Answering</p>

<hr>

<p>And for now you can use 'BERT':</p>

<p>Google release the source code as well as pretrained models.</p>

<p><a href="https://github.com/google-research/bert" rel="noreferrer">https://github.com/google-research/bert</a></p>

<p>And here is an example to run bert as a service:</p>

<p><a href="https://github.com/hanxiao/bert-as-service" rel="noreferrer">https://github.com/hanxiao/bert-as-service</a></p>
How to get vector for a sentence from the word2vec of tokens in sentence
<p>I have generated the vectors for a list of tokens from a large document using word2vec. Given a sentence, is it possible to get the vector of the sentence from the vector of the tokens in the sentence. </p>