/*
* RapidMiner
*
* Copyright (C) 2001-2011 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapid-i.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.postprocessing;
import java.util.Iterator;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.AttributeTypeException;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.UserError;
import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.operator.ports.metadata.ExampleSetPrecondition;
import com.rapidminer.tools.Ontology;
/**
* This operator applies the given threshold to an example set and maps a soft
* prediction to crisp values. If the confidence for the second class (usually
* positive for RapidMiner) is greater than the given threshold the prediction is set
* to this class.
*
* @author Ingo Mierswa, Martin Scholz
*/
public class ThresholdApplier extends Operator {
private InputPort exampleSetInput = getInputPorts().createPort("example set", ExampleSet.class);
private InputPort thresholdInput = getInputPorts().createPort("threshold", Threshold.class);
private OutputPort exampleSetOutput = getOutputPorts().createPort("example set");
public ThresholdApplier(OperatorDescription description) {
super(description);
exampleSetInput.addPrecondition(new ExampleSetPrecondition(exampleSetInput, Ontology.VALUE_TYPE, Attributes.PREDICTION_NAME, Attributes.CONFIDENCE_NAME));
getTransformer().addPassThroughRule(exampleSetInput, exampleSetOutput);
}
@Override
public void doWork() throws OperatorException {
ExampleSet exampleSet = exampleSetInput.getData();
Threshold threshold = thresholdInput.getData();
Attribute predictedLabel = exampleSet.getAttributes().getPredictedLabel();
if (predictedLabel == null)
throw new UserError(this, 107);
int zeroIndex = 0;
int oneIndex = 0;
try {
zeroIndex = predictedLabel.getMapping().mapString(threshold.getZeroClass());
} catch (AttributeTypeException e) {
throw new UserError(this, 147, threshold.getZeroClass());
}
try {
oneIndex = predictedLabel.getMapping().mapString(threshold.getOneClass());
} catch (AttributeTypeException e) {
throw new UserError(this, 147, threshold.getOneClass());
}
Iterator<Example> reader = exampleSet.iterator();
while (reader.hasNext()) {
Example example = reader.next();
double oneClassConfidence = example.getConfidence(threshold.getOneClass());
double crispPrediction = oneClassConfidence > threshold.getThreshold() ? oneIndex : zeroIndex;
example.setValue(predictedLabel, crispPrediction);
}
exampleSetOutput.deliver(exampleSet);
}
}