/*
* 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.features.transformation;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import com.rapidminer.example.Attribute;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.Tools;
import com.rapidminer.example.set.SimpleExampleSet;
import com.rapidminer.example.table.AttributeFactory;
import com.rapidminer.example.table.DataRow;
import com.rapidminer.example.table.DataRowFactory;
import com.rapidminer.example.table.DataRowReader;
import com.rapidminer.example.table.ExampleTable;
import com.rapidminer.example.table.MemoryExampleTable;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorCreationException;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ProcessSetupError.Severity;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.MetaData;
import com.rapidminer.operator.ports.metadata.MetaDataInfo;
import com.rapidminer.operator.ports.metadata.SetRelation;
import com.rapidminer.operator.ports.metadata.SimpleMetaDataError;
import com.rapidminer.operator.ports.quickfix.OperatorInsertionQuickFix;
import com.rapidminer.operator.preprocessing.filter.MissingValueReplenishment;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.OperatorService;
import com.rapidminer.tools.math.Complex;
import com.rapidminer.tools.math.FastFourierTransform;
import com.rapidminer.tools.math.Peak;
import com.rapidminer.tools.math.SpectrumFilter;
import com.rapidminer.tools.math.WindowFunction;
import com.rapidminer.tools.math.container.Range;
/**
* Creates a new example set consisting of the result of a fourier transformation for each attribute of the input
* example set.
*
* @author Ingo Mierswa
*/
public class FourierTransform extends AbstractFeatureTransformation {
public FourierTransform(OperatorDescription description) {
super(description);
}
@Override
protected MetaData modifyMetaData(ExampleSetMetaData metaData) throws UndefinedParameterError {
for (AttributeMetaData amd : metaData.getAllAttributes()) {
if (!amd.isSpecial()) {
if (amd.containsMissingValues() == MetaDataInfo.YES) {
getExampleSetInputPort().addError(new SimpleMetaDataError(Severity.ERROR, getExampleSetInputPort(), Collections.singletonList(new OperatorInsertionQuickFix("insert_missing_value_replenishment", new String[0], 1, getExampleSetInputPort()) {
@Override
public Operator createOperator() throws OperatorCreationException {
return OperatorService.createOperator(MissingValueReplenishment.class);
}
}), "exampleset.contains_missings", getName()));
break;
}
}
}
// create transformed meta data
List<AttributeMetaData> newAttributes = new LinkedList<AttributeMetaData>();
for (AttributeMetaData amd : metaData.getAllAttributes()) {
if (!amd.isSpecial() && amd.isNumerical()) {
AttributeMetaData newAttribute = new AttributeMetaData("fft(" + amd.getName() + ")", Ontology.REAL);
newAttribute.setValueRange(new Range(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY), SetRelation.UNKNOWN);
newAttributes.add(newAttribute);
}
}
metaData.clearRegular();
metaData.clear();
AttributeMetaData frequency = new AttributeMetaData("frequency", Ontology.REAL);
metaData.addAttribute(frequency);
metaData.addAllAttributes(newAttributes);
if (metaData.getNumberOfExamples().isKnown())
metaData.setNumberOfExamples(FastFourierTransform.getGreatestPowerOf2LessThan(metaData.getNumberOfExamples().getValue()) / 2);
return metaData;
}
@Override
public ExampleSet apply(ExampleSet exampleSet) throws OperatorException {
Tools.onlyNonMissingValues(exampleSet, "Fourier Transform");
// create new example table
int numberOfNewExamples = FastFourierTransform.getGreatestPowerOf2LessThan(exampleSet.size()) / 2;
ExampleTable exampleTable = new MemoryExampleTable(new LinkedList<Attribute>(), new DataRowFactory(DataRowFactory.TYPE_DOUBLE_ARRAY, '.'), numberOfNewExamples);
// create frequency attribute (for frequency)
Attribute frequencyAttribute = AttributeFactory.createAttribute("frequency", Ontology.REAL);
exampleTable.addAttribute(frequencyAttribute);
DataRowReader drr = exampleTable.getDataRowReader();
int k = 0;
while (drr.hasNext()) {
DataRow dataRow = drr.next();
dataRow.set(frequencyAttribute, FastFourierTransform.convertFrequency(k++, numberOfNewExamples, exampleSet.size()));
}
// create FFT values
List<Attribute> attributes = new LinkedList<Attribute>();
attributes.add(frequencyAttribute);
Attribute label = exampleSet.getAttributes().getLabel();
// add FFT values
FastFourierTransform fft = new FastFourierTransform(WindowFunction.BLACKMAN_HARRIS);
SpectrumFilter filter = new SpectrumFilter(SpectrumFilter.NONE);
for (Attribute current : exampleSet.getAttributes()) {
if (current.isNumerical()) {
Complex[] result = fft.getFourierTransform(exampleSet, label, current);
Peak[] spectrum = filter.filter(result, exampleSet.size());
// create new attribute and fill table with values
Attribute newAttribute = AttributeFactory.createAttribute("fft(" + current.getName() + ")", Ontology.REAL);
exampleTable.addAttribute(newAttribute);
attributes.add(newAttribute);
fillTable(exampleTable, newAttribute, spectrum);
}
}
ExampleSet resultSet = new SimpleExampleSet(exampleTable);
return resultSet;
}
/**
* Fills the table with the length of the given complex numbers in the column of the attribute.
*/
private void fillTable(ExampleTable table, Attribute attribute, Peak[] values) throws OperatorException {
DataRowReader reader = table.getDataRowReader();
int k = 0;
while (reader.hasNext()) {
DataRow dataRow = reader.next();
dataRow.set(attribute, values[k++].getMagnitude());
checkForStop();
}
}
/**
* This constructs a new table and hence doesn't modify existing example set
*/
@Override
public boolean writesIntoExistingData() {
return false;
}
}