jidt/java/source/infodynamics/measures/continuous/kraskov/TransferEntropyCalculatorKr...

190 lines
8.4 KiB
Java
Executable File

/*
* Java Information Dynamics Toolkit (JIDT)
* Copyright (C) 2012, Joseph T. Lizier
*
* 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 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package infodynamics.measures.continuous.kraskov;
import java.util.Hashtable;
import infodynamics.measures.continuous.ConditionalMutualInfoCalculatorMultiVariate;
import infodynamics.measures.continuous.TransferEntropyCalculator;
import infodynamics.measures.continuous.TransferEntropyCalculatorViaCondMutualInfo;
/**
*
* <p>
* Implements a transfer entropy calculator using a conditional MI calculator
* implementing the Kraskov-Grassberger estimator.
* This is achieved by plugging in a {@link ConditionalMutualInfoCalculatorMultiVariateKraskov}
* as the calculator into {@link TransferEntropyCalculatorViaCondMutualInfo}.
* </p>
*
* <p>
* Usage:
* <ol>
* <li>Construct: {@link #TransferEntropyCalculatorKraskov()}</li>
* <li>Set properties: {@link #setProperty(String, String)} for each relevant property, including those
* of either {@link TransferEntropyCalculatorViaCondMutualInfo#setProperty(String, String)}
* or {@link ConditionalMutualInfoCalculatorMultiVariateKraskov#setProperty(String, String)}.</li>
* <li>Initialise: by calling one of {@link #initialise()} etc.</li>
* <li>Add observations to construct the PDFs: {@link #setObservations(double[])}, or [{@link #startAddObservations()},
* {@link #addObservations(double[])}*, {@link #finaliseAddObservations()}]
* Note: If not using setObservations(), the results from computeLocal
* will be concatenated directly, and getSignificance will mix up observations
* from separate trials (added in separate {@link #addObservations(double[])} calls.</li>
* <li>Compute measures: e.g. {@link #computeAverageLocalOfObservations()} or
* {@link #computeLocalOfPreviousObservations()} etc </li>
* </ol>
* </p>
*
* @author Joseph Lizier, <a href="joseph.lizier at gmail.com">email</a>,
* <a href="http://lizier.me/joseph/">www</a>
* @see "Kraskov, A., Stoegbauer, H., Grassberger, P., Physical Review E 69, (2004) 066138;
* <a href='http://dx.doi.org/10.1103/PhysRevE.69.066138'>download</a>
* (for introduction of Kraskov-Grassberger method for MI)"
* @see "G. Gomez-Herrero, W. Wu, K. Rutanen, M. C. Soriano, G. Pipa, and R. Vicente,
* arXiv:1008.0539, 2010;
* <a href='http://arxiv.org/abs/1008.0539'>download</a>
* (for introduction of Kraskov-Grassberger technique to transfer entropy)"
* @see TransferEntropyCalculator
*
*/
public class TransferEntropyCalculatorKraskov
extends TransferEntropyCalculatorViaCondMutualInfo {
public static final String COND_MI_CALCULATOR_KRASKOV1 = ConditionalMutualInfoCalculatorMultiVariateKraskov1.class.getName();
public static final String COND_MI_CALCULATOR_KRASKOV2 = ConditionalMutualInfoCalculatorMultiVariateKraskov2.class.getName();
/**
* Property for setting which underlying Kraskov-Grassberger algorithm to use.
* Will only be applied at the next initialisation.
*/
public final static String PROP_KRASKOV_ALG_NUM = "ALG_NUM";
protected int kraskovAlgorithmNumber = 1;
protected boolean algChanged = false;
/**
* Storage for the properties ready to pass onto the underlying conditional MI calculators should they change
*/
protected Hashtable<String,String> props;
/**
* Creates a new instance of the Kraskov-estimate style transfer entropy calculator
*
* Uses algorithm 1 by default, as per Gomez-Herro et al.
*
* @throws ClassNotFoundException
* @throws IllegalAccessException
* @throws InstantiationException
*
*/
public TransferEntropyCalculatorKraskov() throws InstantiationException, IllegalAccessException, ClassNotFoundException {
super(COND_MI_CALCULATOR_KRASKOV1);
kraskovAlgorithmNumber = 1;
props = new Hashtable<String,String>();
}
/**
* Creates a new instance of the Kraskov-Grassberger style transfer entropy calculator,
* with the supplied conditional MI calculator name
*
* @param calculatorName fully qualified name of the underlying MI class.
* Must be {@link #COND_MI_CALCULATOR_KRASKOV1} or {@link #COND_MI_CALCULATOR_KRASKOV2}
* @throws ClassNotFoundException
* @throws IllegalAccessException
* @throws InstantiationException
*
*/
public TransferEntropyCalculatorKraskov(String calculatorName) throws InstantiationException, IllegalAccessException, ClassNotFoundException {
super(calculatorName);
// Now check that it was one of our Kraskov-Grassberger calculators:
if (calculatorName.equalsIgnoreCase(COND_MI_CALCULATOR_KRASKOV1)) {
kraskovAlgorithmNumber = 1;
} else if (calculatorName.equalsIgnoreCase(COND_MI_CALCULATOR_KRASKOV2)) {
kraskovAlgorithmNumber = 2;
} else {
throw new ClassNotFoundException("Must be an underlying Kraskov-Grassberger conditional MI calculator");
}
props = new Hashtable<String,String>();
}
/* (non-Javadoc)
* @see infodynamics.measures.continuous.TransferEntropyCalculatorViaCondMutualInfo#initialise(int, int, int, int, int)
*/
@Override
public void initialise(int k, int k_tau, int l, int l_tau, int delay)
throws Exception {
if (algChanged) {
// The algorithm number was changed in a setProperties call:
String newCalcName = COND_MI_CALCULATOR_KRASKOV1;
if (kraskovAlgorithmNumber == 2) {
newCalcName = COND_MI_CALCULATOR_KRASKOV2;
}
@SuppressWarnings("unchecked")
Class<ConditionalMutualInfoCalculatorMultiVariate> condMiClass =
(Class<ConditionalMutualInfoCalculatorMultiVariate>) Class.forName(newCalcName);
ConditionalMutualInfoCalculatorMultiVariate newCondMiCalc = condMiClass.newInstance();
construct(newCondMiCalc);
// Set the properties for the Kraskov MI calculators (may pass in properties for our super class
// as well, but they should be ignored)
for (String key : props.keySet()) {
newCondMiCalc.setProperty(key, props.get(key));
}
algChanged = false;
}
super.initialise(k, k_tau, l, l_tau, delay);
}
/**
* Sets properties for the calculator.
* Valid properties include:
* <ul>
* <li>{@link #PROP_KRASKOV_ALG_NUM} - which Kraskov algorithm number to use (1 or 2). Will only be applied at the next initialisation.</li>
* <li>Any valid properties for {@link TransferEntropyCalculatorViaCondMutualInfo#setProperty(String, String)}</li>
* <li>Any valid properties for {@link ConditionalMutualInfoCalculatorMultiVariateKraskov#setProperty(String, String)}</li>
* </ul>
* One should set {@link ConditionalMutualInfoCalculatorMultiVariateKraskov#PROP_K} here, the number
* of neighbouring points one should count up to in determining the joint kernel size.
*
* @param propertyName name of the property
* @param propertyValue value of the property (as a string)
*/
public void setProperty(String propertyName, String propertyValue)
throws Exception {
if (propertyName.equalsIgnoreCase(PROP_KRASKOV_ALG_NUM)) {
int previousAlgNumber = kraskovAlgorithmNumber;
kraskovAlgorithmNumber = Integer.parseInt(propertyValue);
if ((kraskovAlgorithmNumber != 1) && (kraskovAlgorithmNumber != 2)) {
throw new Exception("Kraskov algorithm number (" + kraskovAlgorithmNumber
+ ") must be either 1 or 2");
}
if (kraskovAlgorithmNumber != previousAlgNumber) {
algChanged = true;
}
if (debug) {
System.out.println(this.getClass().getSimpleName() + ": Set property " + propertyName +
" to " + propertyValue);
}
} else {
// Assume it was a property for the parent class or underlying conditional MI calculator
super.setProperty(propertyName, propertyValue);
props.put(propertyName, propertyValue); // This will keep properties for the super class as well as the cond MI calculator, but this is ok
}
}
}