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///////////////////////////////////////////////////////////////////////////////
// For information as to what this class does, see the Javadoc, below. //
// Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, //
// 2007, 2008, 2009, 2010, 2014, 2015, 2022 by Peter Spirtes, Richard //
// Scheines, Joseph Ramsey, and Clark Glymour. //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation; either version 2 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 General Public License for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program; if not, write to the Free Software //
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA //
///////////////////////////////////////////////////////////////////////////////
package edu.cmu.tetradapp.editor;
import cern.jet.random.engine.MersenneTwister;
import edu.cmu.tetrad.data.ContinuousVariable;
import edu.cmu.tetrad.data.DataSet;
import edu.cmu.tetrad.graph.Node;
import org.apache.commons.math3.util.FastMath;
import javax.swing.*;
/**
* Immutable object that wraps a dataset and gives a q-q plot.
*
* @author Michael Freenor
*/
class QQPlot {
/**
* The complete data set
*/
private final DataSet dataSet;
/**
* The variable that we are showing a q-q plot for.
*/
private ContinuousVariable selectedVariable;
/**
* The variable that we store the comparison variable in
*/
private double[] comparisonVariable;
/**
* The min value in the comparison distribution
*/
private double minComparison;
/**
* The max value in the comparison distribution
*/
private double maxComparison;
/**
* The min value in the sample
*/
private double minData;
/**
* The max value in the sample
*/
private double maxData;
/**
* Constructs the histogram given the dataset to wrap and the node that should be viewed.
*
* @param dataSet a {@link edu.cmu.tetrad.data.DataSet} object
* @param selectedNode a {@link edu.cmu.tetrad.graph.Node} object
*/
public QQPlot(DataSet dataSet, Node selectedNode) {
if (dataSet == null) {
throw new NullPointerException("the given dataset must not be null");
}
if (dataSet.getNumColumns() == 0) {
throw new IllegalArgumentException("The given dataset should not be empty");
}
for (int i = 0; i < dataSet.getNumColumns(); i++) {
if (dataSet.getVariable(i) instanceof ContinuousVariable) {
break;
}
if (i == dataSet.getNumColumns() - 1) {
JOptionPane.showMessageDialog(new JFrame(), "You must have at least one continuous variable to construct a q-q plot!");
throw new IllegalArgumentException("You must have at least one continuous variable to construct a q-q plot!");
}
}
this.dataSet = dataSet.copy();
if (selectedNode == null && dataSet.getNumColumns() != 0) {
int[] selected = dataSet.getSelectedIndices();
assert selected != null;
}
try {
this.selectedVariable = (ContinuousVariable) selectedNode;
} catch (Exception e) {
JOptionPane.showMessageDialog(new JFrame(), "You cannot construct a q-q plot for a discrete variable!");
throw new IllegalArgumentException("Only attempt to construct a q-q plot on a continuous variable!");
}
buildQQPlotData(this.selectedVariable);
}
//==================================== Public Methods ====================================//
/**
* @param quantile Desired quantile you wish to find
* @param low The minimum of your dataset
* @param high The maximum of your dataset
* @param n Your normal distribution you wish to search among
* @param precision The desired precision of your search (in quantiles)
* @param count Feed this zero -- ensures the stack doesn't fill up
* @param searchCap Desired maximum number of searches -- too high and the stack might overflow!
* @return an estimation of the point in a Normal distribution at a specific quantile.
*/
private static double findQuantile(double quantile, double low, double high, cern.jet.random.Normal n, double precision, int count, int searchCap) {
//System.out.println("Low: " + low + "High: " + high);
double mid = low + ((high - low) / 2.);
//System.out.println("Mid: " + mid);
double cdfResult = n.cdf(mid);
//System.out.println("CDF: " + cdfResult + " Abs value of difference: " + FastMath.abs(cdfResult - quantile) + " Count: " + count);
if (
FastMath.abs(cdfResult - quantile) < precision || count > searchCap) {
//System.out.println("Found result: " + mid);
return mid;
} else {
if (cdfResult > quantile) {
//System.out.println("Searching lesser");
return QQPlot.findQuantile(quantile, low, mid - precision, n, precision, count + 1, searchCap);
} else {
//System.out.println("Searching greater");
return QQPlot.findQuantile(quantile, mid + precision, high, n, precision, count + 1, searchCap);
}
}
}
/**
* getMaxSample.
*
* @return the max sample value.
*/
public double getMaxSample() {
return this.maxData;
}
/**
* getMinSample.
*
* @return the min sample value.
*/
public double getMinSample() {
return this.minData;
}
/**
* getMinIdeal.
*
* @return the min comparison value.
*/
public double getMinIdeal() {
return this.minComparison;
}
/**
* Getter for the field selectedVariable.
*
* @return the node that has been selected.
*/
public Node getSelectedVariable() {
return this.selectedVariable;
}
/**
* Setter for the field selectedVariable.
*
* @param c a {@link edu.cmu.tetrad.data.ContinuousVariable} object
*/
public void setSelectedVariable(ContinuousVariable c) {
this.selectedVariable = c;
}
/**
* Getter for the field comparisonVariable.
*
* @return an array of objects
*/
public double[] getComparisonVariable() {
return this.comparisonVariable;
}
//============================ Private Methods =======================//
/**
* Getter for the field dataSet.
*
* @return a {@link edu.cmu.tetrad.data.DataSet} object
*/
public DataSet getDataSet() {
return this.dataSet;
}
/**
* Calculates the ideal quantiles values for the provided dataset.
*
* @param n Normal distribution generated from the dataset.
* @param data Dataset that n is generated from, and whose normality is in question.
*/
private void calculateComparisonSet(cern.jet.random.Normal n, DataSet data) {
this.comparisonVariable = new double[data.getNumRows()];
for (int i = 0; i < data.getNumRows(); i++) {
double valueAtQuantile = QQPlot.findQuantile((i + 1) / (data.getNumRows() + 1.0), this.minData, this.maxData, n, .0001, 0, 50);
this.comparisonVariable[i] = valueAtQuantile;
if (valueAtQuantile < this.minComparison) {
this.minComparison = valueAtQuantile;
}
if (valueAtQuantile > this.maxComparison) {
this.maxComparison = valueAtQuantile;
}
}
}
/**
* Builds the q-q data if required, otherwise does nothing
*/
private void buildQQPlotData(Node selectedNode) {
int columnIndex = this.dataSet.getColumn(selectedNode);
double mean = 0.0;
double sd = 0.0;
this.minData = 10000000000000.0;
this.maxData = 0.0;
this.minComparison = 1000000000000.0;
this.maxComparison = 0.0;
//the only case in which this should be -1 is if there's a continuous variable, but it's incomplete
if (columnIndex == -1) {
for (int i = 0; i < this.dataSet.getNumColumns(); i++) {
//set selected variable if there is none
if (this.dataSet.getVariable(i) instanceof ContinuousVariable) {
this.selectedVariable = (ContinuousVariable) this.dataSet.getVariable(i);
columnIndex = i;
break;
}
}
if (columnIndex == -1) {
JOptionPane.showMessageDialog(new JFrame(), "You need at least one complete continuous variable for a q-q plot!");
throw new IllegalArgumentException("You need at least one complete continuous variable for a q-q plot!");
}
}
for (int i = 0; i < this.dataSet.getNumRows(); i++) {
double value = this.dataSet.getDouble(i, columnIndex);
if (Double.isNaN(value) || value == Double.NEGATIVE_INFINITY
|| value == Double.POSITIVE_INFINITY) {
continue;
}
mean += value;
if (value < this.minData) this.minData = value;
if (value > this.maxData) this.maxData = value;
}
//sort the dataset
for (int i = 0; i < this.dataSet.getNumRows(); i++) {
for (int k = i; k < this.dataSet.getNumRows(); k++) {
double value1 = this.dataSet.getDouble(i, columnIndex);
double value2 = this.dataSet.getDouble(k, columnIndex);
if (Double.isNaN(value1) || value1 == Double.NEGATIVE_INFINITY
|| value1 == Double.POSITIVE_INFINITY) {
continue;
}
if (Double.isNaN(value2) || value2 == Double.NEGATIVE_INFINITY
|| value2 == Double.POSITIVE_INFINITY) {
continue;
}
if (value1 > value2) {
double temp = this.dataSet.getDouble(i, columnIndex);
this.dataSet.setDouble(i, columnIndex, value2);
this.dataSet.setDouble(k, columnIndex, temp);
}
}
}
if (mean == 0.0) mean = 1.0;
else mean /= this.dataSet.getNumRows();
for (int i = 0; i < this.dataSet.getNumRows(); i++) {
double value1 = this.dataSet.getDouble(i, columnIndex);
double value2 = this.dataSet.getDouble(i, columnIndex);
if (Double.isNaN(value1) || value1 == Double.NEGATIVE_INFINITY
|| value1 == Double.POSITIVE_INFINITY) {
continue;
}
if (Double.isNaN(value2) || value2 == Double.NEGATIVE_INFINITY
|| value2 == Double.POSITIVE_INFINITY) {
continue;
}
sd += (value1 - mean) * (value2 - mean);
}
if (sd == 0.0) {
sd = 1.0;
} else {
sd /= this.dataSet.getNumRows() - 1.0;
sd = FastMath.sqrt(sd);
}
//System.out.println("Mean: " + mean + " SD: " + sd + " Min: " + this.minData + " Max: " + this.maxData);
cern.jet.random.Normal comparison = new cern.jet.random.Normal(mean, sd, new MersenneTwister());
calculateComparisonSet(comparison, this.dataSet);
}
}
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