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  1. Spark
  2. SPARK-13368

PySpark JavaModel fails to extract params from Spark side automatically

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Details

    • Bug
    • Status: Resolved
    • Minor
    • Resolution: Duplicate
    • None
    • None
    • PySpark
    • None

    Description

      JavaModel fails to extract params from Spark side automatically that causes model.extractParamMap() is always empty. As shown in the example code below copied from Spark Guide https://spark.apache.org/docs/latest/ml-guide.html#example-estimator-transformer-and-param

          # Prepare training data from a list of (label, features) tuples.
          training = sqlContext.createDataFrame([
              (1.0, Vectors.dense([0.0, 1.1, 0.1])),
              (0.0, Vectors.dense([2.0, 1.0, -1.0])),
              (0.0, Vectors.dense([2.0, 1.3, 1.0])),
              (1.0, Vectors.dense([0.0, 1.2, -0.5]))], ["label", "features"])
      
          # Create a LogisticRegression instance. This instance is an Estimator.
          lr = LogisticRegression(maxIter=10, regParam=0.01)
          # Print out the parameters, documentation, and any default values.
          print "LogisticRegression parameters:\n" + lr.explainParams() + "\n"
      
          # Learn a LogisticRegression model. This uses the parameters stored in lr.
          model1 = lr.fit(training)
      
          # Since model1 is a Model (i.e., a transformer produced by an Estimator),
          # we can view the parameters it used during fit().
          # This prints the parameter (name: value) pairs, where names are unique
          # IDs for this LogisticRegression instance.
          print "Model 1 was fit using parameters: "
          print model1.extractParamMap()
      

      The result of model1.extractParamMap() is {}.

      Question is, should we provide the feature or not? If yes, we need either let Model share same params with Estimator or adds a parent in Model and points to its Estimator; if not, we should remove those lines from example code.

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              Unassigned Unassigned
              yinxusen Xusen Yin
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                Updated:
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