jidt/java/source/infodynamics/measures/continuous/TransferEntropyCalculatorMu...

484 lines
21 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;
import java.util.Vector;
import infodynamics.utils.MatrixUtils;
/**
* A Multivariate Transfer Entropy (TE) calculator (implementing
* {@link TransferEntropyCalculatorMultiVariate})
* which is affected using a
* given Conditional Mutual Information (MI) calculator (implementing
* {@link ConditionalMutualInfoCalculatorMultiVariate}) to make the calculations.
*
* <p>Usage is as per the paradigm outlined for {@link TransferEntropyCalculatorMultiVariate},
* except that in the constructor(s) for this class the implementation for
* a {@link ConditionalMutualInfoCalculatorMultiVariate} must be supplied.
* </p>
*
* <p>This class <i>may</i> be used directly, however users are advised that
* several child classes are available which already plug-in the various
* conditional MI estimators
* to provide TE calculators (taking specific caution associated with
* each type of estimator):</p>
* <ul>
* <li>{@link infodynamics.measures.continuous.gaussian.TransferEntropyCalculatorMultiVariateGaussian}</li>
* <li>{@link infodynamics.measures.continuous.kraskov.TransferEntropyCalculatorMultiVariateKraskov}</li>
* </ul>
*
* <p>This implementation inherits from the {@link TransferEntropyCalculatorViaCondMutualInfo},
* so the univariate methods for adding observations etc are still available, however
* they will throw Exceptions if this calculator was not initialised for single
* dimensional data sets.
* </p>
*
* <p><b>References:</b><br/>
* <ul>
* <li>T. Schreiber, <a href="http://dx.doi.org/10.1103/PhysRevLett.85.461">
* "Measuring information transfer"</a>,
* Physical Review Letters 85 (2) pp.461-464, 2000.</li>
* <li>J. T. Lizier, M. Prokopenko and A. Zomaya,
* <a href="http://dx.doi.org/10.1103/PhysRevE.77.026110">
* "Local information transfer as a spatiotemporal filter for complex systems"</a>
* Physical Review E 77, 026110, 2008.</li>
* <li>J.T. Lizier, J. Heinzle, A. Horstmann, J.-D. Haynes, M. Prokopenko,
* <a href="http://dx.doi.org/10.1007/s10827-010-0271-2">
* "Multivariate information-theoretic measures reveal directed information
* structure and task relevant changes in fMRI connectivity"</a>,
* Journal of Computational Neuroscience, vol. 30, pp. 85-107, 2011.</li>
* </ul>
*
* @author Joseph Lizier, <a href="joseph.lizier at gmail.com">email</a>,
* <a href="http://lizier.me/joseph/">www</a>
* @see TransferEntropyCalculatorViaCondMutualInfo
* @see TransferEntropyCalculatorMultiVariate
* @see TransferEntropyCalculator
*/
public class TransferEntropyCalculatorMultiVariateViaCondMutualInfo
extends TransferEntropyCalculatorViaCondMutualInfo
// which means we implement TransferEntropyCalculator
implements TransferEntropyCalculatorMultiVariate {
/**
* Number of dimensions of the destination
*/
protected int destDimensions = 1;
/**
* Number of dimensions of the source
*/
protected int sourceDimensions = 1;
/**
* Construct a transfer entropy calculator using an instance of
* condMiCalculatorClassName as the underlying conditional mutual information calculator.
*
* @param condMiCalculatorClassName fully qualified name of the class which must implement
* {@link ConditionalMutualInfoCalculatorMultiVariate}
* @throws InstantiationException if the given class cannot be instantiated
* @throws IllegalAccessException if illegal access occurs while trying to create an instance
* of the class
* @throws ClassNotFoundException if the given class is not found
*/
public TransferEntropyCalculatorMultiVariateViaCondMutualInfo(String condMiCalculatorClassName)
throws InstantiationException, IllegalAccessException, ClassNotFoundException {
super(condMiCalculatorClassName);
}
/**
* Construct a transfer entropy calculator using an instance of
* condMiCalcClass as the underlying conditional mutual information calculator.
*
* @param condMiCalcClass the class which must implement
* {@link ConditionalMutualInfoCalculatorMultiVariate}
* @throws InstantiationException if the given class cannot be instantiated
* @throws IllegalAccessException if illegal access occurs while trying to create an instance
* of the class
* @throws ClassNotFoundException if the given class is not found
*/
public TransferEntropyCalculatorMultiVariateViaCondMutualInfo(Class<ConditionalMutualInfoCalculatorMultiVariate> condMiCalcClass)
throws InstantiationException, IllegalAccessException, ClassNotFoundException {
super(condMiCalcClass);
}
/**
* Construct this calculator by passing in a constructed but not initialised
* underlying Conditional Mutual information calculator.
*
* @param condMiCalc An instantiated conditional mutual information calculator.
* @throws Exception if the supplied calculator has not yet been instantiated.
*/
public TransferEntropyCalculatorMultiVariateViaCondMutualInfo(ConditionalMutualInfoCalculatorMultiVariate condMiCalc) throws Exception {
super(condMiCalc);
}
/* (non-Javadoc)
* @see infodynamics.measures.continuous.ChannelCalculatorMultiVariate#initialise(int, int)
*/
@Override
public void initialise(int sourceDimensions, int destDimensions)
throws Exception {
initialise(sourceDimensions, destDimensions, k, k_tau, l, l_tau, delay);
}
/* (non-Javadoc)
* @see infodynamics.measures.continuous.TransferEntropyCalculatorMultiVariate#initialise(int, int, int)
*/
@Override
public void initialise(int k, int sourceDimensions, int destDimensions)
throws Exception {
initialise(sourceDimensions, destDimensions, k, k_tau, l, l_tau, delay);
}
/* (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 {
initialise(sourceDimensions, destDimensions, k, k_tau, l, l_tau, delay);
}
/**
* Initialise the calculator for re-use with new observations.
* New embedding parameters, source and dest dimensions
* and source-destination delay
* may be supplied here; all other parameters
* remain unchanged.
*
* @param sourceDimensions dimensionality of the source variable
* @param destDimensions dimensionality of the destination variable
* @param k Length of destination past history to consider
* @param k_tau embedding delay for the destination variable
* @param l length of source past history to consider
* @param l_tau embedding delay for the source variable
* @param delay time lag between last element of source and destination next value
*/
public void initialise(int sourceDimensions, int destDimensions, int k, int k_tau, int l, int l_tau, int delay) throws Exception {
if (delay < 0) {
throw new Exception("Cannot compute TE with source-destination delay < 0");
}
this.sourceDimensions = sourceDimensions;
this.destDimensions = destDimensions;
this.k = k;
this.k_tau = k_tau;
this.l = l;
this.l_tau = l_tau;
this.delay = delay;
// Now check which point we can start taking observations from in any
// addObservations call. These two integers represent the last
// point of the destination embedding, in the cases where the destination
// embedding itself determines where we can start taking observations, or
// the case where the source embedding plus delay is longer and so determines
// where we can start taking observations.
int startTimeBasedOnDestPast = (k-1)*k_tau;
int startTimeBasedOnSourcePast = (l-1)*l_tau + delay - 1;
startTimeForFirstDestEmbedding = Math.max(startTimeBasedOnDestPast, startTimeBasedOnSourcePast);
condMiCalc.initialise(l*sourceDimensions, destDimensions, k*destDimensions);
}
/* (non-Javadoc)
* @see infodynamics.measures.continuous.ChannelCalculatorMultiVariate#setObservations(double[][], double[][])
*/
@Override
public void setObservations(double[][] source, double[][] destination)
throws Exception {
if (source.length != destination.length) {
throw new Exception(String.format("Source and destination lengths (%d and %d) must match!",
source.length, destination.length));
}
if ((sourceDimensions == 1) && (destDimensions == 1)) {
// We'll be using the superclass for the computation
super.setObservations(MatrixUtils.selectColumn(source, 0),
MatrixUtils.selectColumn(destination, 0));
return;
}
if (source.length < startTimeForFirstDestEmbedding + 2) {
// There are no observations to add here, the time series is too short
throw new Exception("Not enough observations to set here given k, k_tau, l, l_tau and delay parameters");
}
double[][] currentDestPastVectors =
MatrixUtils.makeDelayEmbeddingVector(destination, k, k_tau,
startTimeForFirstDestEmbedding,
destination.length - startTimeForFirstDestEmbedding - 1);
double[][] currentDestNextVectors =
MatrixUtils.makeDelayEmbeddingVector(destination, 1,
startTimeForFirstDestEmbedding + 1,
destination.length - startTimeForFirstDestEmbedding - 1);
double[][] currentSourcePastVectors =
MatrixUtils.makeDelayEmbeddingVector(source, l, l_tau,
startTimeForFirstDestEmbedding + 1 - delay,
source.length - startTimeForFirstDestEmbedding - 1);
condMiCalc.setObservations(currentSourcePastVectors, currentDestNextVectors, currentDestPastVectors);
}
@Override
public void startAddObservations() {
if ((sourceDimensions == 1) && (destDimensions == 1)) {
// We'll be using the superclass for the computation
super.startAddObservations();
return;
}
// Otherwise initialise ourselves:
condMiCalc.startAddObservations();
}
/**
* <p>Adds a new set of <b>univariate</b> observations to compute the PDFs from.
* Can only be called on this multivariate calculator if the dimensions
* of both source and destination are 1, otherwise throws an exception</p>
*
* {@inheritDoc}
*
* @param source univariate observations for the source variable
* @param destination univariate observations for the destination variable
* @throws Exception if initialised dimensions were not 1
* @see {@link ChannelCalculator#addObservations(double[], double[])}
*/
@Override
public void addObservations(double[] source, double[] destination) throws Exception {
if ((sourceDimensions != 1) || (destDimensions != 1)) {
throw new Exception("Cannot call the univariate addObservations if you " +
"have initialised with dimension > 1 for either source or destination");
}
super.addObservations(source, destination);
}
/* (non-Javadoc)
* @see infodynamics.measures.continuous.ChannelCalculatorMultiVariate#addObservations(double[][], double[][])
*/
@Override
public void addObservations(double[][] source, double[][] destination)
throws Exception {
if (source.length != destination.length) {
throw new Exception(String.format("Source and destination lengths (%d and %d) must match!",
source.length, destination.length));
}
if ((sourceDimensions == 1) && (destDimensions == 1)) {
// We'll be using the superclass for the computation
super.addObservations(MatrixUtils.selectColumn(source, 0),
MatrixUtils.selectColumn(destination, 0));
return;
}
if (source.length < startTimeForFirstDestEmbedding + 2) {
// There are no observations to add here, the time series is too short
// Don't throw an exception, do nothing since more observations
// can be added later.
return;
}
double[][] currentDestPastVectors =
MatrixUtils.makeDelayEmbeddingVector(destination, k, k_tau,
startTimeForFirstDestEmbedding,
destination.length - startTimeForFirstDestEmbedding - 1);
double[][] currentDestNextVectors =
MatrixUtils.makeDelayEmbeddingVector(destination, 1,
startTimeForFirstDestEmbedding + 1,
destination.length - startTimeForFirstDestEmbedding - 1);
double[][] currentSourcePastVectors =
MatrixUtils.makeDelayEmbeddingVector(source, l, l_tau,
startTimeForFirstDestEmbedding + 1 - delay,
source.length - startTimeForFirstDestEmbedding - 1);
condMiCalc.addObservations(currentSourcePastVectors, currentDestNextVectors, currentDestPastVectors);
}
/**
* <p>Adds a new sub-series of <b>univariate</b> observations to compute the PDFs from.
* Can only be called on this multivariate calculator if the dimensions
* of both source and destination are 1, otherwise throws an exception</p>
*
* {@inheritDoc}
*
* @param source univariate observations for the source variable
* @param destination univariate observations for the destination variable
* @throws Exception if initialised dimensions were not 1
* @see {@link ChannelCalculator#addObservations(double[], double[], int, int)}
*/
@Override
public void addObservations(double[] source, double[] destination,
int startTime, int numTimeSteps) throws Exception {
if ((sourceDimensions != 1) || (destDimensions != 1)) {
throw new Exception("Cannot call the univariate addObservations if you " +
"have initialised with dimension > 1 for either source or destination");
}
super.addObservations(source, destination, startTime, numTimeSteps);
}
/* (non-Javadoc)
* @see infodynamics.measures.continuous.ChannelCalculatorMultiVariate#addObservations(double[][], double[][], int, int)
*/
@Override
public void addObservations(double[][] source, double[][] destination,
int startTime, int numTimeSteps) throws Exception {
if (source.length != destination.length) {
throw new Exception(String.format("Source and destination lengths (%d and %d) must match!",
source.length, destination.length));
}
if ((sourceDimensions == 1) && (destDimensions == 1)) {
// We'll be using the superclass for the computation
super.addObservations(MatrixUtils.selectColumn(source, 0),
MatrixUtils.selectColumn(destination, 0),
startTime, numTimeSteps);
return;
}
if (source.length < startTime + numTimeSteps) {
// There are not enough observations given the arguments here
throw new Exception("Not enough observations to set here given startTime and numTimeSteps parameters");
}
addObservations(MatrixUtils.selectRows(source, startTime, numTimeSteps),
MatrixUtils.selectRows(destination, startTime, numTimeSteps));
}
/**
* <p>Adds a new sub-series of <b>univariate</b> observations to compute the PDFs from.
* Can only be called on this multivariate calculator if the dimensions
* of both source and destination are 1, otherwise throws an exception</p>
*
* {@inheritDoc}
*
* @param source univariate observations for the source variable
* @param destination univariate observations for the destination variable
* @throws Exception if initialised dimensions were not 1
* @see {@link ChannelCalculator#setObservations(double[], double[], boolean[], boolean[])}
*/
public void setObservations(double[] source, double[] destination,
boolean[] sourceValid, boolean[] destValid) throws Exception {
if ((sourceDimensions != 1) || (destDimensions != 1)) {
throw new Exception("Cannot call the univariate setObservations if you " +
"have initialised with dimension > 1 for either source or destination");
}
super.setObservations(source, destination, sourceValid, destValid);
}
/* (non-Javadoc)
* @see infodynamics.measures.continuous.ChannelCalculatorMultiVariate#setObservations(double[][], double[][], boolean[], boolean[])
*/
@Override
public void setObservations(double[][] source, double[][] destination,
boolean[] sourceValid, boolean[] destValid) throws Exception {
if ((sourceDimensions == 1) && (destDimensions == 1)) {
// We'll be using the superclass for the computation
super.setObservations(MatrixUtils.selectColumn(source, 0),
MatrixUtils.selectColumn(destination, 0),
sourceValid, destValid);
return;
}
Vector<int[]> startAndEndTimePairs = computeStartAndEndTimePairs(sourceValid, destValid);
// We've found the set of start and end times for this pair
startAddObservations();
for (int[] timePair : startAndEndTimePairs) {
int startTime = timePair[0];
int endTime = timePair[1];
addObservations(source, destination, startTime, endTime - startTime + 1);
}
finaliseAddObservations();
}
/* (non-Javadoc)
* @see infodynamics.measures.continuous.ChannelCalculatorMultiVariate#setObservations(double[][], double[][], boolean[][], boolean[][])
*/
@Override
public void setObservations(double[][] source, double[][] destination,
boolean[][] sourceValid, boolean[][] destValid) throws Exception {
if ((sourceDimensions == 1) && (destDimensions == 1)) {
// We'll be using the superclass for the computation
super.setObservations(MatrixUtils.selectColumn(source, 0),
MatrixUtils.selectColumn(destination, 0),
MatrixUtils.selectColumn(sourceValid, 0),
MatrixUtils.selectColumn(destValid, 0));
return;
}
boolean[] jointSourceValid = MatrixUtils.andRows(sourceValid);
boolean[] jointDestValid = MatrixUtils.andRows(destValid);
setObservations(source, destination, jointSourceValid, jointDestValid);
}
@Override
public void finaliseAddObservations() throws Exception {
if ((sourceDimensions == 1) && (destDimensions == 1)) {
// We'll be using the superclass for the computation
super.finaliseAddObservations();
return;
}
// Otherwise finalise ourselves:
condMiCalc.finaliseAddObservations();
}
/**
* <p>Computes the local values of the transfer entropy
* for each valid observation in the supplied univariate observations
* Can only be called on this multivariate calculator if the dimensions
* of both source and destination are 1, otherwise throws an exception</p>
*
* {@inheritDoc}
*
* @param newSourceObservations univariate observations for the source variable
* @param newDestObservations univariate observations for the destination variable
* @throws Exception if initialised dimensions were not 1
*/
public double[] computeLocalUsingPreviousObservations(double[] newSourceObservations,
double[] newDestObservations) throws Exception {
if ((sourceDimensions != 1) || (destDimensions != 1)) {
throw new Exception("Cannot call the univariate computeLocalUsingPreviousObservations if you " +
"have initialised with dimension > 1 for either source or destination");
}
return super.computeLocalUsingPreviousObservations(newSourceObservations, newDestObservations);
}
@Override
public double[] computeLocalUsingPreviousObservations(double[][] newSourceObservations,
double[][] newDestObservations) throws Exception {
if (newSourceObservations.length != newDestObservations.length) {
throw new Exception(String.format("Source and destination lengths (%d and %d) must match!",
newSourceObservations.length, newDestObservations.length));
}
if (newDestObservations.length < startTimeForFirstDestEmbedding + 2) {
// There are no observations to compute for here
return new double[newDestObservations.length];
}
double[][] newDestPastVectors =
MatrixUtils.makeDelayEmbeddingVector(newDestObservations, k, k_tau,
startTimeForFirstDestEmbedding,
newDestObservations.length - startTimeForFirstDestEmbedding - 1);
double[][] newDestNextVectors =
MatrixUtils.makeDelayEmbeddingVector(newDestObservations, 1,
startTimeForFirstDestEmbedding + 1,
newDestObservations.length - startTimeForFirstDestEmbedding - 1);
double[][] newSourcePastVectors =
MatrixUtils.makeDelayEmbeddingVector(newSourceObservations, l, l_tau,
startTimeForFirstDestEmbedding + 1 - delay,
newSourceObservations.length - startTimeForFirstDestEmbedding - 1);
double[] local = condMiCalc.computeLocalUsingPreviousObservations(
newSourcePastVectors, newDestNextVectors, newDestPastVectors);
// Pad the front of the array with zeros where local TE isn't defined:
double[] localsToReturn = new double[local.length + startTimeForFirstDestEmbedding + 1];
System.arraycopy(local, 0, localsToReturn, startTimeForFirstDestEmbedding + 1, local.length);
return localsToReturn;
}
}