Adding python examples 5 and 6. Minor tweaks to octave examples 5 and 6 to clarify comments or minor conflicts. Error corrected in comment of python example 2

This commit is contained in:
joseph.lizier 2013-06-07 05:58:47 +00:00
parent 88b33308c6
commit f006c53e46
5 changed files with 127 additions and 6 deletions

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@ -8,11 +8,12 @@ javaaddpath('../../infodynamics.jar');
% Generate some random binary data.
% Note that we need the *1 to make this a number not a Boolean,
% otherwise this will not work (as it cannot match the method signature)
sourceArray=(rand(1000,2)>0.5)*1;
sourceArray2=(rand(1000,2)>0.5)*1;
numObservations = 100;
sourceArray=(rand(numObservations,2)>0.5)*1;
sourceArray2=(rand(numObservations,2)>0.5)*1;
% Destination variable takes a copy of the first bit of the source in bit 1,
% and an XOR of the two bits of the source in bit 2:
destArray = [0, 0; sourceArray(1:99, 1), xor(sourceArray(1:99, 1), sourceArray(1:99, 2))];
destArray = [0, 0; sourceArray(1:numObservations-1, 1), xor(sourceArray(1:numObservations-1, 1), sourceArray(1:numObservations-1, 2))];
% Create a TE calculator and run it:
teCalc=javaObject('infodynamics.measures.discrete.ApparentTransferEntropyCalculator', 4, 1);
teCalc.initialise();
@ -28,5 +29,5 @@ teCalc.addObservations(mUtils.computeCombinedValues(octaveToJavaDoubleMatrix(des
mUtils.computeCombinedValues(octaveToJavaDoubleMatrix(sourceArray2), 2));
fprintf('For random source, result should be close to 0 bits in theory: ');
result2 = teCalc.computeAverageLocalOfObservations()
fprintf('\nThe result for random source is inflated towards 0.3 due to finite observation length. One can verify that the answer is consistent with that from a random source by checking: teCalc.computeSignificance(1000); ans.pValue\n');
fprintf('\nThe result for random source is inflated towards 0.3 due to finite observation length (%d). One can verify that the answer is consistent with that from a random source by checking: teCalc.computeSignificance(1000); ans.pValue\n', teCalc.getNumObservations());

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@ -25,7 +25,7 @@ variable2Columns = [3,4];
% infodynamics.measures.continuous.MutualInfoCalculatorMultiVariate
% which we wish to use for the calculation.
% Note that one could use any of the following calculators (try them all!):
% implementingClass = "infodynamics.measures.continuous.kraskov.MutualInfoCalculatorMultiVariateKraskov1";
% implementingClass = "infodynamics.measures.continuous.kraskov.MutualInfoCalculatorMultiVariateKraskov1"; % MI([1,2], [3,4]) = 0.35507
% implementingClass = "infodynamics.measures.continuous.kernel.MutualInfoCalculatorMultiVariateKernel";
% implementingClass = "infodynamics.measures.continuous.gaussian.MutualInfoCalculatorMultiVariateGaussian";
implementingClass = "infodynamics.measures.continuous.kraskov.MutualInfoCalculatorMultiVariateKraskov1";

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@ -13,7 +13,7 @@ jarLocation = "../../infodynamics.jar"
startJVM(getDefaultJVMPath(), "-ea", "-Djava.class.path=" + jarLocation)
# Create many columns in a multidimensional array, e.g. for fully random values:
# twoDTimeSeriesOctave = [[random.randint(0,1)]*2 for x in xrange(10)] # for 10 rows (time-steps) for 2 variables
# twoDTimeSeriesOctave = [[random.randint(0,1) for y in xrange(2)] for x in xrange(10)] # for 10 rows (time-steps) for 2 variables
# However here we want 2 rows by 100 columns where the next time step (row 2) is to copy the
# value of the column on the left from the previous time step (row 1):

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@ -0,0 +1,41 @@
# = Example 5 - Multivariate transfer entropy on binary data =
# Multivariate transfer entropy (TE) calculation on binary data using the discrete TE calculator:
from jpype import *
import random
from operator import xor
# Change location of jar to match yours:
jarLocation = "../../infodynamics.jar"
# Start the JVM (add the "-Xmx" option with say 1024M if you get crashes due to not enough memory space)
startJVM(getDefaultJVMPath(), "-ea", "-Djava.class.path=" + jarLocation)
# Generate some random binary data.
numObservations = 100
sourceArray = [[random.randint(0,1) for y in xrange(2)] for x in xrange(numObservations)] # for 10 rows (time-steps) for 2 variables
sourceArray2= [[random.randint(0,1) for y in xrange(2)] for x in xrange(numObservations)] # for 10 rows (time-steps) for 2 variables
# Destination variable takes a copy of the first bit of the source in bit 1,
# and an XOR of the two bits of the source in bit 2:
destArray = [[0, 0]]
for j in range(1,numObservations):
destArray.append([sourceArray[j-1][0], xor(sourceArray[j-1][0], sourceArray[j-1][1])])
# Create a TE calculator and run it:
teCalcClass = JPackage("infodynamics.measures.discrete").ApparentTransferEntropyCalculator
teCalc = teCalcClass(4,1)
teCalc.initialise()
# We need to construct the joint values of the dest and source before we pass them in,
# and need to use the matrix conversion routine when calling from Matlab/Octave:
mUtils= JPackage('infodynamics.utils').MatrixUtils
teCalc.addObservations(mUtils.computeCombinedValues(destArray, 2), \
mUtils.computeCombinedValues(sourceArray, 2))
result = teCalc.computeAverageLocalOfObservations()
print('For source which the 2 bits are determined from, result should be close to 2 bits : %.3f' % result)
teCalc.initialise()
teCalc.addObservations(mUtils.computeCombinedValues(destArray, 2), \
mUtils.computeCombinedValues(sourceArray2, 2))
result2 = teCalc.computeAverageLocalOfObservations()
print('For random source, result should be close to 0 bits in theory: %.3f' % result2)
print('The result for random source is inflated towards 0.3 due to finite observation length (%d). One can verify that the answer is consistent with that from a random source by checking: teCalc.computeSignificance(1000); ans.pValue\n' % teCalc.getNumObservations())

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@ -0,0 +1,79 @@
# = Example 6 - Mutual information calculation with dynamic specification of calculator =
# This example shows how to write Python code to take advantage of the
# common interfaces defined for various information-theoretic calculators.
# Here, we use the common form of the infodynamics.measures.continuous.MutualInfoCalculatorMultiVariate
# interface (which is never named here) to write common code into which we can plug
# one of three concrete implementations (kernel estimator, Kraskov estimator or
# linear-Gaussian estimator) by dynamically supplying the class name of
# the concrete implementation.
#
# This is the Python equivalent to the demos/java/lateBindingDemo
from jpype import *
import random
import string
import numpy
# Change location of jar to match yours:
jarLocation = "../../infodynamics.jar"
# Start the JVM (add the "-Xmx" option with say 1024M if you get crashes due to not enough memory space)
startJVM(getDefaultJVMPath(), "-ea", "-Djava.class.path=" + jarLocation)
#---------------------
# 1. Properties for the calculation (these are dynamically changeable):
# The name of the data file (relative to this directory)
datafile = '../data/4ColsPairedNoisyDependence-1.txt'
# List of column numbers for variables 1 and 2:
# (you can select any columns you wish to be contained in each variable)
variable1Columns = [0,1] # array indices start from 0 in python
variable2Columns = [2,3]
# The name of the concrete implementation of the interface
# infodynamics.measures.continuous.MutualInfoCalculatorMultiVariate
# which we wish to use for the calculation.
# Note that one could use any of the following calculators (try them all!):
# implementingClass = "infodynamics.measures.continuous.kraskov.MutualInfoCalculatorMultiVariateKraskov1" # MI([0,1], [2,3]) = 0.35507
# implementingClass = "infodynamics.measures.continuous.kernel.MutualInfoCalculatorMultiVariateKernel"
# implementingClass = "infodynamics.measures.continuous.gaussian.MutualInfoCalculatorMultiVariateGaussian"
implementingClass = "infodynamics.measures.continuous.kraskov.MutualInfoCalculatorMultiVariateKraskov1"
#---------------------
# 2. Load in the data (space separate numbers, one time step per line, each column is a variable)
f = open(datafile)
data = []
for line in f:
data.append([float(x) for x in line.split()])
# As numpy array:
A = numpy.array(data)
# Pull out the columns from the data set which correspond to each of variable 1 and 2:
variable1 = A[:,variable1Columns]
variable2 = A[:,variable2Columns]
#--------------------
# 3. Dynamically instantiate an object of the given class:
# (in fact, all java object creation in python is dynamic - it has to be,
# since the languages are interpreted. This makes our life slightly easier at this
# point than it is in demos/java/lateBindingDemo where we have to handle this manually)
indexOfLastDot = string.rfind(implementingClass, ".")
implementingPackage = implementingClass[:indexOfLastDot]
implementingBaseName = implementingClass[indexOfLastDot+1:]
miCalcClass = eval('JPackage(\'%s\').%s' % (implementingPackage, implementingBaseName))
miCalc = miCalcClass()
#--------------------
# 4. Start using the MI calculator, paying attention to only
# call common methods defined in the interface type
# infodynamics.measures.continuous.MutualInfoCalculatorMultiVariate
# not methods only defined in a given implementation class.
# a. Initialise the calculator to use the required number of
# dimensions for each variable:
miCalc.initialise(len(variable1Columns), len(variable2Columns))
# b. Supply the observations to compute the PDFs from:
miCalc.setObservations(variable1, variable2)
# c. Make the MI calculation:
miValue = miCalc.computeAverageLocalOfObservations()
print("MI calculator %s computed the joint MI as %.5f\n" % (implementingClass, miValue))