title: gensim doc2vec train more documents from pre-trained model
body: <p>I am trying to train with new labelled document(TaggedDocument) with the pre-trained model.</p>
  
  <p>Pretrained model is the trained model with documents which the unique id with label1_index, for instance, Good_0, Good_1 to Good_999
  And the total size of trained data is about 7000</p>
  
  <p>Now, I want to train the pre-trained model with new documents which the unique id with label2_index, for instance, Bad_0, Bad_1... to Bad_1211
  And the total size of trained data is about 1211</p>
  
  <p>The train itself was successful without any error, but the problem is that whenever I try to use 'most_similar' it only suggests the similar document labelled with Good_... where I expect the labelled with Bad_.</p>
  
  <p>If I train altogether from the beginning, it gives me the answers I expected - it infers a newly given document similar to either labelled with Good or Bad. </p>
  
  <p>However, the practice above will not work as the one trained altogether from the beginning.</p>
  
  <p>Is continuing train not working properly or did I make some mistake?</p>