How to specify the "positive class" in sparkml binary classification? (Or perhaps: How does a MulticlassClassificationEvaluator <https://spark.apache.org/docs/latest/api/python/reference/api/pyspark.ml.evaluation.MulticlassClassificationEvaluator.html?highlight=multiclassclassificationevaluator> determine which class is the "positive" one when evaluating for, say, F1 or even just Recall?) I have a Pipeline like...
pipeline = Pipeline(stages=[label_idxer, feature_idxer, onehotencoder, assembler, my_ml_algo, label_converter]) crossval = CrossValidator(estimator=pipeline, evaluator=MulticlassClassificationEvaluator( labelCol=my_ml_algo.getLabelCol(), predictionCol=my_ml_algo.getPredictionCol(), metricName="f1"), numFolds=3) Is there a way to specify which label or index is the positive/negative class?