The "Transparency" Library

Scalable and Fast, local (single level) and global (population level) prediction explanation of:

• Ensemble trees (e.g., XGB, GBM, RF, and Decision tree)
• Generalized linear models GLM (support for various families, link powers, and variance powers, e.g., logistic regression)

implemented for models in:

• Python (Scikit-Learn)
• Pyspark (Scala and Pyspark)

Installation:

• pip install transparency

additional step for Spark users:

• Add this jar to spark classpath : https://github.com/alvinhenrick/spark_model_explainer/releases/download/v.0.0.1/spark_model_explainer-assembly-0.0.1.jar (Maven repository release will soon be supported : https://github.com/clarifyhealth/spark_model_explainer)

Transformer Set

- Scikit-Learn Ensemble Tree Explainer Transformer

from transparency.python.explainer.ensemble_tree import EnsembleTreeExplainerTransformer
expl = EnsembleTreeExplainerTransformer(estimator)
X_test_df = expl.transform(X_test_df)

• estimator: the ensemble tree estimator that has been trained (e.g., random forest, gbm, or xgb)
• X_test: a Pandas dataframe with features as columns and samples as rows The resulting X_test_df will have 3 added columns: 'prediction', 'feature_contributions' and 'intercept_contribution':
• 'feature_contributions': column of nested arrays with feature contributions (1 array per row)
• 'intercept_contribution': column of the same scaler value representing the contribution of the intercept sum(contributions) + contrib_intercept for each row equals the prediction for that row.

- Scikit-Learn Generalized Linear Model (e.g., Logistic regression) Explainer Transformer

from transparency.python.explainer.glm import GLMExplainerTransformer
expl = GLMExplainerTransformer(estimator)
X_test_df = expl.transform(X_test_df, output_proba=False)

• estimator: the glm estimator that has been trained (e.g., logistic regression)
• X_test: a Pandas dataframe with features as columns and samples as rows The resulting X_test_df will have 3 added columns: 'prediction', 'feature_contributions' and 'intercept_contribution':
• 'feature_contributions': column of nested arrays with feature contributions (1 array per row)
• 'intercept_contribution': column of the same scaler value representing the contribution of the intercept sum(contributions) + contrib_intercept for each row equals the prediction for that row.
• if output_proba is set to True, for the case of logistic regression, the output prediction and its corresponding explanation will be proba instead of the classification result

- Pyspark Ensemble Tree Explainer Transformer

 from transparency.spark.prediction.explainer.tree import EnsembleTreeExplainTransformer
 EnsembleTreeExplainTransformer(predictionView=predictions_view, 
                                featureImportanceView=features_importance_view,
                                modelPath=rf_model_path, 
                                label=label_column,
                                dropPathColumn=True, 
                                isClassification=classification, 
                                ensembleType=ensemble_type)

• Path to load model modelPath

• Supported ensembleType

  1. dct
  2. gbt
  3. rf
  4. xgboost4j

• The feature importance extracted from Apache Spark Model Meta Data.featureImportanceView Reference this python script : testutil.common.get_feature_importance

  1. Feature_Index
  2. Feature
  3. Original_Feature
  4. Importance

• The transformer append 3 main column to the prediction view

  1. contrib_column ==> f"{prediction_{label_column}_contrib : array of contributions
  2. contrib_column_sum ==> f"{contrib_column}_sum"
  3. contrib_column_intercept ==> f"{contrib_column}_intercept"

- Pyspark Generalized Linear Model (GLM) Explainer Transformer

  from transparency.spark.prediction.explainer.tree import GLMExplainTransformer
  GLMExplainTransformer(predictionView=predictions_view, 
                        coefficientView=coefficients_view,
                        linkFunctionType=link_function_type, 
                        label=label_column, nested=True,
                        calculateSum=True, 
                        family=family, 
                        variancePower=variance_power, 
                        linkPower=link_power)

• Supported linkFunctionType

  1. logLink
  2. powerHalfLink
  3. identityLink
  4. logitLink
  5. inverseLink
  6. otherPowerLink

• The feature coefficient extracted from Apache Spark Model Meta Data.coefficientView Reference this python script : testutil.common.get_feature_coefficients

  1. Feature_Index
  2. Feature
  3. Original_Feature
  4. Coefficient

• The transformer append 3 main column to the prediction view

  1. contrib_column ==> f"{prediction_{label_column}_contrib : array of contributions
  2. contrib_column_sum ==> f"{contrib_column}_sum"
  3. contrib_column_intercept ==> f"{contrib_column}_intercept"

Example Notebooks

• Python (Scikit-Learn) Ensemble Tree Explain Example: https://github.com/imanbio/transparency/blob/master/examples/notebooks/python/python_ensemble_tree_explainer_samples.ipynb
• Python (Scikit-Learn) Generalized Linear Model Explain Example: https://github.com/imanbio/transparency/blob/master/examples/notebooks/python/python_glm_explainer_samples.ipynb
• PySpark GLM Explain Example: https://github.com/imanbio/transparency/blob/master/examples/notebooks/spark/pyspark_glm_explain.ipynb
• PySpark Random Forest Explain Example: https://github.com/imanbio/transparency/blob/master/examples/notebooks/spark/pyspark_random_forest_explain.ipynb

Authors

• Iman Haji https://www.linkedin.com/in/imanhaji
• Imran Qureshi https://www.linkedin.com/in/imranq2/
• Alvin Henrick https://www.linkedin.com/in/alvinhenrick/

License

Apache License Version 2.0