title: Does Word2Vec in Spark trains on whole text column
body: <p>I have a question pertaining to the amount of data Word2Vec method in Spark takes while training the algorithm. </p>
  
  <p>So given a data set like below: </p>
  
  <pre><code>+----------+--------------------+--------------------+
  |        id|               title|        text_cleaned|
  +----------+--------------------+--------------------+
  | -33753621|Royal Bank of Sco...|If you hate deali...|
  |-761323061|Teen sexting is p...|Rampant teen sext...|
  +----------+--------------------+--------------------+
  only showing top 2 rows
  </code></pre>
  
  <p>I want to use the text documents in column text_cleaned as the input data to convert it into Word2Vec embeddings for each doc (each row in text_cleaned is a doc). </p>
  
  <p>Here is what I do: </p>
  
  <pre><code>   def word2Vec(df):
          """ This function takes in the data frame of the texts and finds the   
          Word vector representation of that
  
          """
  
  
  
  
          from pyspark.ml.feature import Tokenizer, Word2Vec
          # Carrying out the Tokenization of the text documents (splitting int0 
  
          words)
  
          tokenizer = Tokenizer(inputCol="text_cleaned",   
          outputCol="tokenised_text")
          tokensDf = tokenizer.transform(df)
  
          # Implementing the word2Vec model
  
          word2Vec = Word2Vec(vectorSize=300, seed=42, inputCol="tokenised_text",       
          outputCol="w2v_vector")
          w2vmodel = word2Vec.fit(tokensDf)
          w2vdf=w2vmodel.transform(tokensDf)
  
  
      w2vdf,w2vmodel=word2Vec(df_cleaned)
  </code></pre>
  
  <p>It gives me a transformed data which looks like this: </p>
  
  <pre><code>[Row(id=u'-33753621', tokenised_text=[u'if', u'you', u'hate', u'dealing', u'with', u'bank', u'tellers', u'or', u'customer', u'service', u'representatives,', u'then', u'the', u'royal', u'bank', u'of', u'scotland', u'might', u'have', u'a', u'solution', u'for', u'you.if', u'this', u'program', u'is', u'successful,', u'it', u'could', u'be', u'a', u'big', u'step', u'forward', u'on', u'the', u'road', u'to', u'automated', u'customer', u'service', u'through', u'the', u'use', u'of', u'ai,', u'notes', u'laurie', u'beaver,', u'research', u'associate', u'for', u'bi', u'intelligence,', u'business', u"insider's", u'premium', u'research', u"service.it's", u'noteworthy', u'that', u'luvo', u'does', u'not', u'operate', u'via', u'a', u'third-party', u'app', u'such', u'as', u'facebook', u'messenger,', u'wechat,', u'or', u'kik,', u'all', u'of', u'which', u'are', u'currently', u'trying', u'to', u'create', u'bots', u'that', u'would', u'assist', u'in', u'customer', u'service', u'within', u'their', u'respective', u'platforms.luvo', u'would', u'be', u'available', u'through', u'the', u'web', u'and', u'through', u'smartphones.', u'it', u'would', u'also', u'use', u'machine', u'learning', u'to', u'learn', u'from', u'its', u'mistakes,', u'which', u'should', u'ultimately', u'help', u'with', u'its', u'response', u'accuracy.down', u'the', u'road,', u'luvo', u'would', u'become', u'a', u'supplement', u'to', u'the', u'human', u'staff.', u'it', u'can', u'currently', u'answer', u'20', u'set', u'questions', u'but', u'as', u'that', u'number', u'grows,', u'it', u'would', u'allow', u'the', u'human', u'employees', u'to', u'more', u'complicated', u'issues.', u'if', u'a', u'problem', u'is', u'beyond', u"luvo's", u'comprehension,', u'then', u'it', u'would', u'refer', u'the', u'customer', u'to', u'a', u'bank', u'employee;', u'however,\xa0a', u'user', u'could', u'choose', u'to', u'speak', u'with', u'a', u'human', u'instead', u'of', u'luvo', u'anyway.ai', u'such', u'as', u'luvo,', u'if', u'successful,', u'could', u'help', u'businesses', u'become', u'more', u'efficient', u'and', u'increase', u'their', u'productivity,', u'while', u'simultaneously', u'improving', u'customer', u'service', u'capacity,', u'which', u'would', u'consequently\xa0save', u'money', u'that', u'would', u'otherwise', u'go', u'toward', u'manpower.and', u'this', u'trend', u'is', u'already', u'starting.', u'google,', u'microsoft,', u'and', u'ibm', u'are', u'investing', u'significantly', u'into', u'ai', u'research.', u'furthermore,', u'the', u'global', u'ai', u'market', u'is', u'estimated', u'to', u'grow', u'from', u'approximately', u'$420', u'million', u'in', u'2014', u'to', u'$5.05', u'billion', u'in', u'2020,', u'according', u'to', u'a', u'forecast', u'by', u'research', u'and', u'markets.\xa0the', u'move', u'toward', u'ai', u'would', u'be', u'just', u'one', u'more', u'way', u'in', u'which', u'the', u'digital', u'age', u'is', u'disrupting', u'retail', u'banking.', u'customers,', u'particularly', u'millennials,', u'are', u'increasingly', u'moving', u'toward', u'digital', u'banking,', u'and', u'as', u'a', u'result,', u"they're", u'walking', u'into', u'their', u"banks'", u'traditional', u'brick-and-mortar', u'branches', u'less', u'often', u'than', u'ever', u'before.'], w2v_vector=DenseVector([-0.0394, -0.0388, 0.0368, -0.0455, 0.0602, -0.0734, 0.0515, -0.0064, -0.068, -0.0438, 0.0671, 0.007, -0.0227, -0.0393, -0.0254, -0.024, 0.0115, 0.0415, -0.0116, -0.0169, 0.0545, -0.0439, 0.0414, 0.0312, -0.028, -0.0085, 0.0234, -0.1321, -0.0364, 0.0921, 0.0208, 0.0156, 0.0071, 0.0186, -0.0455, -0.0634, 0.0379, 0.0148, 0.0401, -0.0395, 0.0334, 0.0026, -0.0748, -0.0242, -0.0373, 0.0602, -0.0341, -0.0181, 0.0723, 0.0012, -0.1177, 0.0319, 0.0322, -0.1054, -0.0011, -0.0415, -0.0161, -0.0472, -0.0785, -0.0219, -0.0311, 0.0296, -0.0149, 0.04, 0.0001, 0.0337, 0.0841, -0.0344, -0.0171, 0.0425, -0.0122, 0.0838, 0.034, 0.0054, 0.0171, 0.0209, 0.0286, -0.0227, -0.0147, 0.0532, -0.027, -0.0645, -0.0858, -0.1444, 0.0824, 0.0128, -0.0485, -0.0378, -0.0229, 0.0331, -0.0248, 0.0427, -0.0624, -0.0324, -0.0271, 0.0135, 0.0504, 0.0028, -0.0772, 0.0121, -0.09, 0.031, -0.0771, -0.0703, 0.0947, 0.0997, -0.0084, 0.0774, 0.0281, 0.0405, -0.0475, 0.0217, 0.0591, 0.0241, -0.0287, 0.1064, 0.059, -0.06, 0.0422, 0.0908, 0.0341, 0.028, -0.0334, 0.0065, -0.0289, -0.0851, -0.0208, 0.0598, -0.0218, 0.001, 0.0049, 0.0257, 0.0076, -0.0599, 0.006, -0.0494, -0.0081, 0.0066, 0.0131, -0.0299, 0.0159, -0.0383, 0.0402, -0.0571, 0.0359, 0.0009, 0.0404, -0.0207, 0.0044, -0.0089, 0.0306, -0.0405, -0.0012, 0.0159, -0.005, -0.031, -0.0016, -0.0081, 0.0123, -0.0364, 0.0161, -0.0383, -0.0303, -0.0073, -0.0184, 0.0399, 0.0412, 0.0278, 0.0455, -0.0304, 0.0145, -0.0163, 0.0631, -0.0423, 0.0239, 0.0801, -0.0659, -0.0382, 0.0138, 0.051, 0.0056, -0.1605, 0.0018, 0.0077, -0.0076, 0.0119, 0.0397, -0.0823, -0.0462, 0.0465, 0.0735, 0.0283, -0.0205, -0.012, 0.0662, 0.0429, 0.0089, -0.0562, 0.1624, 0.0192, 0.0098, -0.0483, 0.0248, 0.0005, -0.0619, -0.0115, 0.0424, -0.0875, 0.0383, -0.0463, -0.0044, -0.0218, 0.014, -0.0404, -0.0198, -0.0162, -0.018, -0.0377, -0.0291, -0.0273, -0.0713, -0.0047, 0.0263, 0.0809, -0.0477, 0.0056, -0.0563, -0.061, -0.0185, 0.0223, -0.0718, 0.0163, 0.0061, -0.0716, -0.0081, 0.0079, 0.0156, -0.0124, -0.0223, -0.0092, -0.0621, 0.0033, 0.031, 0.0509, -0.0548, -0.0121, -0.0276, 0.0176, -0.04, 0.0382, -0.0737, 0.0202, -0.0314, -0.0702, 0.0685, -0.0928, 0.0698, -0.0484, 0.0541, -0.0539, 0.0895, 0.0076, -0.0134, -0.0116, 0.0227, -0.0361, -0.0729, -0.0068, -0.0501, 0.0137, -0.0134, 0.0039, -0.0463, 0.0289, -0.0336, -0.0731, -0.0362, -0.0195, 0.0466, -0.0132, 0.0336, 0.0108, 0.0219, -0.0702, -0.0117, -0.0285, 0.0644, -0.0806, 0.002, -0.0603, 0.0365, 0.0333, 0.0197, -0.037, 0.0983, 0.0011, 0.0436, 0.0506, -0.0089, -0.0134]))]
  </code></pre>
  
  <p>So it does create the Word2Vec id's for each document and adds a new column for that. However my question is this training happens over all the rows (all docs) of text_cleaned column or it just trains it on each row(doc) of text_cleaned column?. My understanding is when I pass a column which consists of rows of text docs, then word2vec takes the whole column and all rows of it and trains the algo on the whole data. Then it uses that trained model and transforms each document and create a word2vec vector for the same. </p>
  
  <p>This is how sic-kit learn also implements any text feature creation and my hope is this is how Spark does it too. But I wanted to confirm if it does train on whole text column data and not just individually on each row separately. </p>
  
  <p>Please guide. </p>