| Interface | Description | 
|---|---|
| VectorTransformer | 
 :: DeveloperApi ::
 Trait for transformation of a vector 
 | 
| Class | Description | 
|---|---|
| ChiSqSelector | 
 Creates a ChiSquared feature selector. 
 | 
| ChiSqSelectorModel | 
 Chi Squared selector model. 
 | 
| ChiSqSelectorModel.SaveLoadV1_0$ | |
| ElementwiseProduct | 
 Outputs the Hadamard product (i.e., the element-wise product) of each input vector with a
 provided "weight" vector. 
 | 
| HashingTF | 
 Maps a sequence of terms to their term frequencies using the hashing trick. 
 | 
| IDF | 
 Inverse document frequency (IDF). 
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| IDF.DocumentFrequencyAggregator | 
 Document frequency aggregator. 
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| IDFModel | 
 Represents an IDF model that can transform term frequency vectors. 
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| Normalizer | 
 Normalizes samples individually to unit L^p^ norm 
 | 
| PCA | 
 A feature transformer that projects vectors to a low-dimensional space using PCA. 
 | 
| PCAModel | 
 Model fitted by  
PCA that can project vectors to a low-dimensional space using PCA. | 
| StandardScaler | 
 Standardizes features by removing the mean and scaling to unit std using column summary
 statistics on the samples in the training set. 
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| StandardScalerModel | 
 Represents a StandardScaler model that can transform vectors. 
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| VocabWord | 
 Entry in vocabulary 
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| Word2Vec | 
 Word2Vec creates vector representation of words in a text corpus. 
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| Word2VecModel | 
 Word2Vec model
 param:  wordIndex maps each word to an index, which can retrieve the corresponding
                  vector from wordVectors
 param:  wordVectors array of length numWords * vectorSize, vector corresponding
                    to the word mapped with index i can be retrieved by the slice
                    (i * vectorSize, i * vectorSize + vectorSize) 
 |