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/*
* 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 infodynamics.utils.ArrayFileReader;
import infodynamics.utils.MathsUtils;
import infodynamics.utils.MatrixUtils;
import infodynamics.utils.RandomGenerator;
public class MutualInfoMultiVariateTester
extends infodynamics.measures.continuous.MutualInfoMultiVariateAbstractTester {
protected String NUM_THREADS_TO_USE_DEFAULT = MutualInfoCalculatorMultiVariateKraskov.USE_ALL_THREADS;
protected String NUM_THREADS_TO_USE = NUM_THREADS_TO_USE_DEFAULT;
/**
* Utility function to create a calculator for the given algorithm number
*
* @param algNumber
* @return
*/
public MutualInfoCalculatorMultiVariateKraskov getNewCalc(int algNumber) {
MutualInfoCalculatorMultiVariateKraskov miCalc = null;
if (algNumber == 1) {
miCalc = new MutualInfoCalculatorMultiVariateKraskov1();
} else if (algNumber == 2) {
miCalc = new MutualInfoCalculatorMultiVariateKraskov2();
}
return miCalc;
}
/**
* Confirm that the local values average correctly back to the average value
*
*
*/
public void checkLocalsAverageCorrectly(int algNumber, String numThreads) throws Exception {
MutualInfoCalculatorMultiVariateKraskov miCalc = getNewCalc(algNumber);
String kraskov_K = "4";
miCalc.setProperty(
MutualInfoCalculatorMultiVariateKraskov.PROP_K,
kraskov_K);
miCalc.setProperty(
MutualInfoCalculatorMultiVariateKraskov.PROP_NUM_THREADS,
numThreads);
super.testLocalsAverageCorrectly(miCalc, 2, 10000);
}
public void testLocalsAverageCorrectly() throws Exception {
checkLocalsAverageCorrectly(1, NUM_THREADS_TO_USE);
checkLocalsAverageCorrectly(2, NUM_THREADS_TO_USE);
}
/**
* Confirm that significance testing doesn't alter the average that
* would be returned.
*
* @throws Exception
*/
public void checkComputeSignificanceDoesntAlterAverage(int algNumber) throws Exception {
MutualInfoCalculatorMultiVariateKraskov miCalc = getNewCalc(algNumber);
String kraskov_K = "4";
miCalc.setProperty(
MutualInfoCalculatorMultiVariateKraskov.PROP_K,
kraskov_K);
miCalc.setProperty(
MutualInfoCalculatorMultiVariateKraskov.PROP_NUM_THREADS,
NUM_THREADS_TO_USE);
super.testComputeSignificanceDoesntAlterAverage(miCalc, 2, 100);
}
public void testComputeSignificanceDoesntAlterAverage() throws Exception {
checkComputeSignificanceDoesntAlterAverage(1);
checkComputeSignificanceDoesntAlterAverage(2);
}
/**
* Utility function to run Kraskov MI for data with known results
*
* @param var1
* @param var2
* @param kNNs array of Kraskov k nearest neighbours parameter to check
* @param expectedResults array of expected results for each k
*/
protected void checkMIForGivenData(double[][] var1, double[][] var2,
int[] kNNs, double[] expectedResults) throws Exception {
// The Kraskov MILCA toolkit MIhigherdim executable
// uses algorithm 2 by default (this is what it means by rectangular):
MutualInfoCalculatorMultiVariateKraskov miCalc = getNewCalc(2);
for (int kIndex = 0; kIndex < kNNs.length; kIndex++) {
int k = kNNs[kIndex];
miCalc.setProperty(
MutualInfoCalculatorMultiVariateKraskov.PROP_K,
Integer.toString(k));
miCalc.setProperty(
MutualInfoCalculatorMultiVariateKraskov.PROP_NUM_THREADS,
NUM_THREADS_TO_USE);
// No longer need to set this property as it's set by default:
//miCalc.setProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_NORM_TYPE,
// EuclideanUtils.NORM_MAX_NORM_STRING);
miCalc.setProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_ADD_NOISE, "0"); // Need consistency for unit tests
miCalc.initialise(var1[0].length, var2[0].length);
miCalc.setObservations(var1, var2);
miCalc.setDebug(true);
double mi = miCalc.computeAverageLocalOfObservations();
miCalc.setDebug(false);
System.out.printf("k=%d: Average MI %.8f (expected %.8f)\n",
k, mi, expectedResults[kIndex]);
// Dropping required accuracy by one order of magnitude, due
// to faster but slightly less accurate digamma estimator change
assertEquals(expectedResults[kIndex], mi, 0.0000001);
}
}
/**
* Test the computed univariate MI against that calculated by Kraskov's own MILCA
* tool on the same data.
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 1 1 3000 <kNearestNeighbours> 0
*
* @throws Exception if file not found
*
*/
public void testUnivariateMIforRandomVariablesFromFile() throws Exception {
// Test set 1:
ArrayFileReader afr = new ArrayFileReader("demos/data/2randomCols-1.txt");
double[][] data = afr.getDouble2DMatrix();
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {1, 2, 3, 4, 5, 6, 10, 15};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA = {-0.05294175, -0.03944338, -0.02190217,
0.00120807, -0.00924771, -0.00316402, -0.00778205, -0.00565778};
System.out.println("Kraskov comparison 1 - univariate random data 1");
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0}),
MatrixUtils.selectColumns(data, new int[] {1}),
kNNs, expectedFromMILCA);
//------------------
// Test set 2:
// We'll just take the first two columns from this data set
afr = new ArrayFileReader("demos/data/4randomCols-1.txt");
data = afr.getDouble2DMatrix();
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA_2 = {-0.04614525, -0.00861460, -0.00164540,
-0.01130354, -0.01339670, -0.00964035, -0.00237072, -0.00096891};
System.out.println("Kraskov comparison 2 - univariate random data 2");
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0}),
MatrixUtils.selectColumns(data, new int[] {1}),
kNNs, expectedFromMILCA_2);
}
/**
* Test the computed multivariate MI against that calculated by Kraskov's own MILCA
* tool on the same data.
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 2 2 3000 <kNearestNeighbours> 0
*
* @throws Exception if file not found
*
*/
public void testMultivariateMIforRandomVariablesFromFile() throws Exception {
// Test set 3:
// We'll just take the first two columns from this data set
ArrayFileReader afr = new ArrayFileReader("demos/data/4randomCols-1.txt");
double[][] data = afr.getDouble2DMatrix();
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {1, 2, 3, 4, 5, 6, 10, 15};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA_2 = {0.02886644, 0.01071634, 0.00186857,
-0.00377259, -0.00634851, -0.00863725, -0.01058087, -0.01106348};
System.out.println("Kraskov comparison 3 - multivariate random data 1");
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0, 1}),
MatrixUtils.selectColumns(data, new int[] {2, 3}),
kNNs, expectedFromMILCA_2);
}
/**
* Test the computed multivariate MI against that calculated by Kraskov's own MILCA
* tool on the same data, using various numbers of threads
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 2 2 3000 <kNearestNeighbours> 0
*
* @throws Exception if file not found
*
*/
public void testMultivariateMIVariousNumThreads() throws Exception {
// Test set 3a and 3b:
// We'll just take the first two columns from this data set
ArrayFileReader afr = new ArrayFileReader("demos/data/4randomCols-1.txt");
double[][] data = afr.getDouble2DMatrix();
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {3, 4};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA_2 = {0.00186857,
-0.00377259};
System.out.println("Kraskov comparison 3a - single threaded");
NUM_THREADS_TO_USE = "1";
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0, 1}),
MatrixUtils.selectColumns(data, new int[] {2, 3}),
kNNs, expectedFromMILCA_2);
System.out.println("Kraskov comparison 3b - dual threaded");
NUM_THREADS_TO_USE = "2";
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0, 1}),
MatrixUtils.selectColumns(data, new int[] {2, 3}),
kNNs, expectedFromMILCA_2);
NUM_THREADS_TO_USE = NUM_THREADS_TO_USE_DEFAULT;
}
/**
* Test the computed multivariate MI against that calculated by Kraskov's own MILCA
* tool on the same data.
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 1 3 3000 <kNearestNeighbours> 0
*
* @throws Exception if file not found
*
*/
public void testImbalancedMultivariateMIforRandomVariablesFromFile() throws Exception {
// Test set 4:
// We'll take MI from first column to the next 3:
ArrayFileReader afr = new ArrayFileReader("demos/data/4randomCols-1.txt");
double[][] data = afr.getDouble2DMatrix();
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {1, 2, 3, 4, 5, 6, 10, 15};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA = {0.02473475, 0.00404451, -0.00454679,
-0.00737512, -0.00464896, -0.00610772, -0.00881741, -0.01306668};
System.out.println("Kraskov comparison 4 - multivariate random data 2 (1 var to 3 vars)");
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0}),
MatrixUtils.selectColumns(data, new int[] {1, 2, 3}),
kNNs, expectedFromMILCA);
}
/**
* Test the computed multivariate MI against that calculated by Kraskov's own MILCA
* tool on the same data.
* This also tests for multithreading with residuals, assuming
* we're running on a 4 processor machine
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 2 2 3030 <kNearestNeighbours> 0
* where the file has the first 30 rows repeated.
*
* Kraskov et al recommend that a small amount of noise should be
* added to the data to avoid issues with repeated scores; this
* can be done in our toolkit by setting the relevant property
*
* @throws Exception if file not found
*
*/
public void testMultivariateMIforRandomVariablesRepeatedDataFromFile() throws Exception {
// Test set 5:
// We'll just take the first two columns from this data set
ArrayFileReader afr = new ArrayFileReader("demos/data/4randomCols-1.txt");
double[][] data = afr.getDouble2DMatrix();
double[][] data2 = new double[data.length + 30][data[0].length];
for (int r = 0; r < data.length; r++) {
for (int c = 0; c < data[r].length; c++) {
data2[r][c] = data[r][c];
}
}
// Repeat the first 30 rows:
for (int r = 0; r < 30; r++) {
for (int c = 0; c < data[r].length; c++) {
data2[r+data.length][c] = data[r][c];
}
}
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {1, 2, 3, 4, 5, 6, 10, 15};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA_2 = {0.16846374, 0.04091779, 0.02069109,
0.00700680, 0.00121768, -0.00134164, -0.00870685, -0.00966508};
System.out.println("Kraskov comparison 5 - multivariate random data 1 with 30 repeated rows");
checkMIForGivenData(MatrixUtils.selectColumns(data2, new int[] {0, 1}),
MatrixUtils.selectColumns(data2, new int[] {2, 3}),
kNNs, expectedFromMILCA_2);
}
/**
* Test the computed multivariate MI against that calculated by Kraskov's own MILCA
* tool on the same data.
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 2 2 3000 <kNearestNeighbours> 0
*
* @throws Exception if file not found
*
*/
public void testMultivariateMIforDependentVariablesFromFile() throws Exception {
// Test set 6:
// We'll just take the first two columns from this data set
ArrayFileReader afr = new ArrayFileReader("demos/data/4ColsPairedDirectDependence-1.txt");
double[][] data = afr.getDouble2DMatrix();
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {1, 2, 3, 4, 5, 6, 10, 15};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA_2 = {5.00322122, 4.29011291, 3.91312749,
3.69192886, 3.52807488, 3.39865354, 3.05327646, 2.79951639};
System.out.println("Kraskov comparison 6 - multivariate dependent data 1");
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0, 1}),
MatrixUtils.selectColumns(data, new int[] {2, 3}),
kNNs, expectedFromMILCA_2);
}
/**
* Test the computed multivariate MI against that calculated by Kraskov's own MILCA
* tool on the same data.
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 2 2 3000 <kNearestNeighbours> 0
*
* @throws Exception if file not found
*
*/
public void testMultivariateMIforNoisyDependentVariablesFromFile() throws Exception {
// Test set 7:
// We'll just take the first two columns from this data set
ArrayFileReader afr = new ArrayFileReader("demos/data/4ColsPairedNoisyDependence-1.txt");
double[][] data = afr.getDouble2DMatrix();
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {1, 2, 3, 4, 5, 6, 10, 15};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA_2 = {0.33738970, 0.36251531, 0.34708687,
0.36200563, 0.35766125, 0.35007623, 0.35023664, 0.33728287};
System.out.println("Kraskov comparison 7 - multivariate dependent data 1");
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0, 1}),
MatrixUtils.selectColumns(data, new int[] {2, 3}),
kNNs, expectedFromMILCA_2);
}
/**
* Test the computed multivariate MI against that calculated by Kraskov's own MILCA
* tool on the same data.
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 5 5 10000 <kNearestNeighbours> 0
*
* @throws Exception if file not found
*
*/
public void testMultivariateMIforRandomGaussianVariablesFromFile() throws Exception {
// Test set 8:
// We'll take the columns from this data set
ArrayFileReader afr = new ArrayFileReader("demos/data/10ColsRandomGaussian-1.txt");
double[][] data = afr.getDouble2DMatrix();
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {1, 2, 4, 10, 15};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA_2 = {0.00815609, 0.00250864, 0.00035825,
0.00172174, 0.00033354};
System.out.println("Kraskov comparison 8 - multivariate uncorrelated Gaussian data 1");
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0, 1, 2, 3, 4}),
MatrixUtils.selectColumns(data, new int[] {5, 6, 7, 8, 9}),
kNNs, expectedFromMILCA_2);
}
/**
* Test the computed multivariate MI against that calculated by Kraskov's own MILCA
* tool on the same data.
*
* To run Kraskov's tool (http://www.klab.caltech.edu/~kraskov/MILCA/) for this
* data, run:
* ./MIxnyn <dataFile> 1 1 10000 <kNearestNeighbours> 0
*
* @throws Exception if file not found
*
*/
public void testMIforRandomGaussianVariablesFromLargeFile() throws Exception {
// Test set 9:
// We'll take the columns from this data set
ArrayFileReader afr = new ArrayFileReader("demos/data/10ColsRandomGaussian-1.txt");
double[][] data = afr.getDouble2DMatrix();
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {1, 2, 4, 10, 15};
// Expected values from Kraskov's MILCA toolkit:
double[] expectedFromMILCA_2 = {0.01542004, 0.01137151, 0.00210945,
0.00159921, 0.00031277};
System.out.println("Kraskov comparison 9 - uncorrelated Gaussian data 1 - large file");
checkMIForGivenData(MatrixUtils.selectColumns(data, new int[] {0}),
MatrixUtils.selectColumns(data, new int[] {1}),
kNNs, expectedFromMILCA_2);
}
/**
* Unit test for MI on new observations.
* We can test this against the calculator itself. If we send in the original data set as new observations,
* we can recreate the neighbour counts (plus one) by setting K to 1 larger (to account for the data point itself), and
* account for the change in bias.
*
* @throws Exception
*/
public void testMultivariateCondMIForNewObservations() throws Exception {
ArrayFileReader afr = new ArrayFileReader("demos/data/4ColsPairedOneStepNoisyDependence-1.txt");
double[][] data = afr.getDouble2DMatrix();
// RandomGenerator rg = new RandomGenerator();
//double[][] data = rg.generateNormalData(50, 4, 0, 1);
// Use various Kraskov k nearest neighbours parameter
int[] kNNs = {4, 10, 15};
System.out.println("Kraskov MI testing new Observations:");
for (int alg = 1; alg < 3; alg++) {
for (int ki = 0; ki < kNNs.length; ki++) {
MutualInfoCalculatorMultiVariateKraskov miCalc = getNewCalc(alg);
MutualInfoCalculatorMultiVariateKraskov miCalcForNew = getNewCalc(alg);
// Let it normalise by default
// And no noise addition to protect the integrity of our neighbour counts under both techniques here:
miCalc.setProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_ADD_NOISE, "0");
miCalcForNew.setProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_ADD_NOISE, "0");
double[][] var1 = MatrixUtils.selectColumns(data, new int[] {0});
double[][] var2 = MatrixUtils.selectColumns(data, new int[] {1});
// Compute MI(0;1|2,3) :
miCalc.setProperty(
MutualInfoCalculatorMultiVariateKraskov.PROP_K,
Integer.toString(kNNs[ki]));
System.out.println("Main calc normalisation is " + miCalc.getProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_NORMALISE));
miCalc.initialise(var1[0].length, var2[0].length);
miCalc.setObservations(var1, var2);
@SuppressWarnings("unused")
double miAverage = miCalc.computeAverageLocalOfObservations();
// Now compute as new observations:
miCalcForNew.setProperty(
MutualInfoCalculatorMultiVariateKraskov.PROP_K,
Integer.toString(kNNs[ki] + 1)); // Using K = K + 1
// condMiCalcForNew.setProperty(
// MutualInfoCalculatorMultiVariateKraskov.PROP_NUM_THREADS,
// "1");
System.out.println("New obs calc normalisation is " + miCalcForNew.getProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_NORMALISE));
miCalcForNew.initialise(var1[0].length, var2[0].length);
miCalcForNew.setObservations(var1, var2);
// condMiCalc.setDebug(true);
//condMiCalcForNew.setDebug(true);
double[] newLocals = miCalcForNew.computeLocalUsingPreviousObservations(var1, var2);
//condMiCalcForNew.setDebug(false);
@SuppressWarnings("unused")
double averageFromNewObservations = MatrixUtils.mean(newLocals);
// We can't check this directly, so test each point individually:
for (int t = 0; t < data.length; t++) {
double[] originalNeighbourCounts = miCalc.partialComputeFromObservations(t, 1, false);
// Need to normalise the data before passing it in here -- this is
// what is happening inside computeLocalUsingPreviousObservations above
double[] newObsNeighbourCounts = miCalcForNew.partialComputeFromNewObservations(
t, 1,
MatrixUtils.normaliseIntoNewArray(var1),
MatrixUtils.normaliseIntoNewArray(var2), false);
// Now check each return count in the array:
if (originalNeighbourCounts[1] != newObsNeighbourCounts[1] - 1) {
System.out.println("Assertion failure for t=" + t + ": expected " + originalNeighbourCounts[1] +
" from original, plus 1, but got " + newObsNeighbourCounts[1]);
System.out.print("Actual raw data was: ");
MatrixUtils.printArray(System.out, data[0]);
}
assertEquals(originalNeighbourCounts[1], newObsNeighbourCounts[1] - 1); // Nx should be 1 higher
assertEquals(originalNeighbourCounts[2], newObsNeighbourCounts[2] - 1); // Ny should be 1 higher
// Now check the local value at each point using these verified counts:
double newLocalValue;
if (alg == 1) {
newLocalValue = miCalcForNew.digammaK -
MathsUtils.digamma((int) newObsNeighbourCounts[1] + 1) -
MathsUtils.digamma((int) newObsNeighbourCounts[2] + 1) +
MathsUtils.digamma(miCalcForNew.getNumObservations() + 1); // correct digammaN for new samples
} else {
newLocalValue = miCalcForNew.digammaK -
(double) 1 / (double) miCalcForNew.k -
MathsUtils.digamma((int) newObsNeighbourCounts[1]) -
MathsUtils.digamma((int) newObsNeighbourCounts[2]) +
MathsUtils.digamma(miCalcForNew.getNumObservations() + 1); // correct digammaN for new samples
}
if (Math.abs(newLocalValue - newLocals[t]) > 0.00000001) {
System.out.printf("t=%d: Assertion failed: computed local was %.5f, local from nn counts was %.5f\n",
t, newLocals[t], newLocalValue);
}
assertEquals(newLocalValue, newLocals[t], 0.00000001);
}
}
}
}
/**
* Test the experimental conditional entropy method
* on random Gaussians
*
* @throws Exception if file not found
*
*/
public void testConditionalEntropyforNoisyIndependentVariablesFromFile() throws Exception {
// We'll just take the first two columns from this data set
// Works well on 10ColsRandomGaussian-1.txt because it is Gaussian
ArrayFileReader afr = new ArrayFileReader("demos/data/10ColsRandomGaussian-1.txt");
double[][] data = afr.getDouble2DMatrix();
// When normalising the marginals to std dev 1, we know that entropy of the marginal
// is expected to be:
double expected_Hx = 0.5 * Math.log(2.0 * Math.PI * Math.E);
System.out.println("Kraskov comparison - conditional entropy");
MutualInfoCalculatorMultiVariateKraskov miCalc = getNewCalc(1);
miCalc.setProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_ADD_NOISE, "0"); // Need consistency for unit tests
int[] numSamplesToCheck = new int[] {1000, 3000, 5000, data.length};
double conditionalEnt = 0, expected_H_X_given_Y = 0;
for (int ni = 0; ni < numSamplesToCheck.length; ni++) {
miCalc.initialise(1, 1);
miCalc.setObservations(
MatrixUtils.selectRowsAndColumns(data, 0, numSamplesToCheck[ni], 0, 1),
MatrixUtils.selectRowsAndColumns(data, 0, numSamplesToCheck[ni], 1, 1));
miCalc.setDebug(true);
double mi = miCalc.computeAverageLocalOfObservations();
miCalc.setDebug(false);
conditionalEnt = miCalc.computeAverageConditionalEntropy();
expected_H_X_given_Y = -mi + expected_Hx;
System.out.printf("k=%s: Average MI %.8f; Average H(X|Y) = %.8f (expected %.8f) from %d samples\n",
miCalc.getProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_K), mi,
conditionalEnt, expected_H_X_given_Y, miCalc.getNumObservations());
}
// Only check the assertion on the full data set:
assertEquals(expected_H_X_given_Y, conditionalEnt, 0.01);
}
/**
* Test the experimental conditional entropy method
* on random coupled uniform variables
*
* @throws Exception if file not found
*
*/
public void testConditionalEntropyforNoisyDependentVariablesFromFile() throws Exception {
// We'll just take the first two columns from this data set
// We'll use 4ColsPairedNoisyDependence where first column is randomly distributed
// on 0..1 and third adds some noise to that.
ArrayFileReader afr = new ArrayFileReader("demos/data/4ColsPairedNoisyDependence-1.txt");
double[][] data = afr.getDouble2DMatrix();
// When the marginal x is uniformly distributed on 0..1, we know that entropy of the marginal
// is expected to be 0 -- when we don't normalise the variables!
double expected_Hx = 0;
System.out.println("Kraskov comparison - conditional entropy");
MutualInfoCalculatorMultiVariateKraskov miCalc = getNewCalc(1);
miCalc.setProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_ADD_NOISE, "0"); // Need consistency for unit tests
miCalc.setProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_NORMALISE, "false"); // Need to avoid normalising for the expected value to hold
int[] numSamplesToCheck = new int[] {1000, 2000, data.length};
double conditionalEnt = 0, expected_H_X_given_Y = 0;
for (int ni = 0; ni < numSamplesToCheck.length; ni++) {
miCalc.initialise(1, 1);
miCalc.setObservations(
MatrixUtils.selectRowsAndColumns(data, 0, numSamplesToCheck[ni], 0, 1),
MatrixUtils.selectRowsAndColumns(data, 0, numSamplesToCheck[ni], 2, 1));
double mi = miCalc.computeAverageLocalOfObservations();
conditionalEnt = miCalc.computeAverageConditionalEntropy();
expected_H_X_given_Y = -mi + expected_Hx;
System.out.printf("k=%s: Average MI %.8f; Average H(X|Y) = %.8f (expected %.8f) from %d samples\n",
miCalc.getProperty(MutualInfoCalculatorMultiVariateKraskov.PROP_K), mi,
conditionalEnt, expected_H_X_given_Y, miCalc.getNumObservations());
}
// Only check the assertion on the full data set:
assertEquals(expected_H_X_given_Y, conditionalEnt, 0.02);
}
/**
* Test that observationSetIndices and observationStartTimePoints are written properly
*
* @throws Exception
*/
public void testObservationSetIndices() throws Exception {
int dimensions = 1;
int timeSteps = 100;
MutualInfoCalculatorMultiVariateKraskov miCalc = getNewCalc(1);
miCalc.initialise(dimensions, dimensions);
// generate some random data
RandomGenerator rg = new RandomGenerator();
double[][] sourceData = rg.generateNormalData(timeSteps, dimensions,
0, 1);
double[][] destData = rg.generateNormalData(timeSteps, dimensions,
0, 1);
// First check that for a simple single observation set everything works:
miCalc.setObservations(sourceData, destData);
int[] observationSetIds = miCalc.getObservationSetIndices();
int[] timeSeriesIndices = miCalc.getObservationTimePoints();
assert(observationSetIds.length == timeSteps);
for (int t = 0; t < timeSteps; t++) {
assertEquals(observationSetIds[t], 0);
assertEquals(timeSeriesIndices[t], t);
}
// Now add the same one twice:
miCalc.initialise(dimensions, dimensions);
miCalc.startAddObservations();
miCalc.addObservations(sourceData, destData);
miCalc.addObservations(sourceData, destData);
miCalc.finaliseAddObservations();
observationSetIds = miCalc.getObservationSetIndices();
timeSeriesIndices = miCalc.getObservationTimePoints();
assert(observationSetIds.length == 2*timeSteps);
for (int t = 0; t < timeSteps; t++) {
assertEquals(observationSetIds[t], 0);
assertEquals(timeSeriesIndices[t], t);
}
for (int t = 0; t < timeSteps; t++) {
assertEquals(observationSetIds[timeSteps + t], 1);
assertEquals(timeSeriesIndices[timeSteps + t], t);
}
// Now add NUM_SEGMENTS randomly chosen segments:
int NUM_SEGMENTS = 10;
int maxLength = 10;
int[] startPoints = rg.generateRandomInts(NUM_SEGMENTS, timeSteps - maxLength);
int[] lengthsMinus1 = rg.generateRandomInts(NUM_SEGMENTS, maxLength - 1); // ensures we don't add segments of length 0
miCalc.initialise(dimensions, dimensions);
miCalc.startAddObservations();
for (int r = 0; r < NUM_SEGMENTS; r++) {
miCalc.addObservations(sourceData, destData, startPoints[r], lengthsMinus1[r]+1);
}
miCalc.finaliseAddObservations();
observationSetIds = miCalc.getObservationSetIndices();
timeSeriesIndices = miCalc.getObservationTimePoints();
assert(observationSetIds.length == MatrixUtils.sum(lengthsMinus1) + NUM_SEGMENTS);
int t = 0;
for (int r = 0; r < NUM_SEGMENTS; r++) {
for (int i = 0; i < lengthsMinus1[r]+1; i++) {
assertEquals(observationSetIds[t], r);
assertEquals(timeSeriesIndices[t], startPoints[r] + i);
t++;
}
}
}
}
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