/*
* DensityEstimate.java
*
* Copyright (c) 2002-2015 Alexei Drummond, Andrew Rambaut and Marc Suchard
*
* This file is part of BEAST.
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership and licensing.
*
* BEAST is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* BEAST 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with BEAST; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301 USA
*/
package dr.inference.trace;
import dr.app.gui.chart.Axis;
import dr.app.gui.chart.LinearAxis;
import dr.stats.Variate;
import dr.util.FrequencyDistribution;
/**
* Creates a simple histogram-based density estimate
*
* @author Andrew Rambaut
* @version $Id$
*/
public class DensityEstimate {
public DensityEstimate(Double[] samples, int minimumBinCount) {
this.samples = new Variate.D(samples);
calculateDensity(this.samples, minimumBinCount);
}
protected void calculateDensity(Variate.D data, int minimumBinCount) {
frequencyDistribution = calculateFrequencies(samples, minimumBinCount);
xCoordinates = new Variate.D();
yCoordinates = new Variate.D();
double x = frequencyDistribution.getLowerBound() - frequencyDistribution.getBinSize();
xCoordinates.add(x + (frequencyDistribution.getBinSize() / 2.0));
yCoordinates.add(0.0);
x += frequencyDistribution.getBinSize();
for (int i = 0; i < frequencyDistribution.getBinCount(); i++) {
xCoordinates.add(x + (frequencyDistribution.getBinSize() / 2.0));
double density = frequencyDistribution.getFrequency(i) / frequencyDistribution.getBinSize() / data.getCount();
yCoordinates.add(density);
x += frequencyDistribution.getBinSize();
}
xCoordinates.add(x + (frequencyDistribution.getBinSize() / 2.0));
yCoordinates.add(0.0);
}
protected FrequencyDistribution calculateFrequencies(Variate data, int minimumBinCount) {
double min = (Double) data.getMin();
double max = (Double) data.getMax();
if (min == max) {
if (min == 0) {
min = -1.0;
} else {
min -= Math.abs(min / 10.0);
}
if (max == 0) {
max = 1.0;
} else {
max += Math.abs(max / 10.0);
}
}
Axis axis = new LinearAxis(Axis.AT_MAJOR_TICK, Axis.AT_MAJOR_TICK);
axis.setRange(min, max);
int majorTickCount = axis.getMajorTickCount();
axis.setPrefNumTicks(majorTickCount, 4);
double binSize = axis.getMinorTickSpacing();
int binCount = (int) ((axis.getMaxAxis() - axis.getMinAxis()) / binSize) + 2;
if (minimumBinCount > 0) {
while (binCount < minimumBinCount) {
majorTickCount++;
axis.setPrefNumTicks(majorTickCount, 4);
binSize = axis.getMinorTickSpacing();
binCount = (int) ((axis.getMaxAxis() - axis.getMinAxis()) / binSize) + 2; // should +2, otherwise the last bar will lose
}
}
FrequencyDistribution frequency = new FrequencyDistribution(axis.getMinAxis(), binCount, binSize);
for (int i = 0; i < data.getCount(); i++) {
frequency.addValue((Double) data.get(i));
}
return frequency;
}
public Variate.D getXCoordinates() {
return xCoordinates;
}
public Variate.D getYCoordinates() {
return yCoordinates;
}
public FrequencyDistribution getFrequencyDistribution() {
return frequencyDistribution;
}
protected final Variate.D samples;
protected Variate.D xCoordinates;
protected Variate.D yCoordinates;
protected FrequencyDistribution frequencyDistribution;
}