/*
* 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.preprocessing.sampling;
import java.util.Collections;
import java.util.List;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ProcessSetupError.Severity;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.MDInteger;
import com.rapidminer.operator.ports.metadata.MetaDataInfo;
import com.rapidminer.operator.ports.metadata.SimpleMetaDataError;
import com.rapidminer.operator.ports.quickfix.ParameterSettingQuickFix;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeInt;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.RandomGenerator;
/**
* Absolute sampling operator. This operator takes a random sample with the
* given size. For example, if the sample size is set to 50, the result will
* have exactly 50 examples randomly drawn from the complete data set. Please
* note that this operator does not sample during a data scan but jumps to the
* rows. It should therefore only be used in case of memory data management and
* not, for example, for database or file management.
*
* @author Ingo Mierswa
*/
public class AbsoluteSampling extends AbstractSamplingOperator {
/** The parameter name for "The number of examples which should be sampled" */
public static final String PARAMETER_SAMPLE_SIZE = "sample_size";
public AbsoluteSampling(OperatorDescription description) {
super(description);
}
@Override
protected MDInteger getSampledSize(ExampleSetMetaData emd) throws UndefinedParameterError {
int absoluteNumber = getParameterAsInt(PARAMETER_SAMPLE_SIZE);
if (emd.getNumberOfExamples().isAtLeast(absoluteNumber) == MetaDataInfo.NO)
getExampleSetInputPort().addError(
new SimpleMetaDataError(Severity.ERROR, getExampleSetInputPort(),
Collections.singletonList(new ParameterSettingQuickFix(this, PARAMETER_SAMPLE_SIZE, emd.getNumberOfExamples().getValue().toString())),
"exampleset.need_more_examples", absoluteNumber + ""));
return new MDInteger(absoluteNumber);
}
@Override
public ExampleSet apply(ExampleSet exampleSet) throws OperatorException {
return exampleSet;
}
@Override
public List<ParameterType> getParameterTypes() {
List<ParameterType> types = super.getParameterTypes();
ParameterType type = new ParameterTypeInt(PARAMETER_SAMPLE_SIZE, "The number of examples which should be sampled", 1, Integer.MAX_VALUE, 100);
type.setExpert(false);
types.add(type);
types.addAll(RandomGenerator.getRandomGeneratorParameters(this));
return types;
}
}