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authorCalvin <calvin@EESI>2013-03-26 13:21:36 -0400
committerCalvin <calvin@EESI>2013-03-26 13:21:36 -0400
commit94da049a53423a9aca04d8376b75347ca7eadcbe (patch)
tree75714a7e2b02b4a9cbd51f0d43b16b6e92dbd4f6 /FEAST/MIToolbox/CalculateProbability.c
parent15094127277f73541a1c2f887caf1c7edda7fdb5 (diff)
moved FEAST Libraries
Diffstat (limited to 'FEAST/MIToolbox/CalculateProbability.c')
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+/*******************************************************************************
+** CalculateProbability.cpp
+** Part of the mutual information toolbox
+**
+** Contains functions to calculate the probability of each state in the array
+** and to calculate the probability of the joint state of two arrays
+**
+** Author: Adam Pocock
+** Created 17/2/2010
+**
+** Copyright 2010 Adam Pocock, The University Of Manchester
+** www.cs.manchester.ac.uk
+**
+** This file is part of MIToolbox.
+**
+** MIToolbox is free software: you can redistribute it and/or modify
+** it under the terms of the GNU Lesser General Public License as published by
+** the Free Software Foundation, either version 3 of the License, or
+** (at your option) any later version.
+**
+** MIToolbox 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 Lesser General Public License for more details.
+**
+** You should have received a copy of the GNU Lesser General Public License
+** along with MIToolbox. If not, see <http://www.gnu.org/licenses/>.
+**
+*******************************************************************************/
+
+#include "MIToolbox.h"
+#include "ArrayOperations.h"
+#include "CalculateProbability.h"
+
+JointProbabilityState calculateJointProbability(double *firstVector, double *secondVector, int vectorLength)
+{
+ int *firstNormalisedVector;
+ int *secondNormalisedVector;
+ int *firstStateCounts;
+ int *secondStateCounts;
+ int *jointStateCounts;
+ double *firstStateProbs;
+ double *secondStateProbs;
+ double *jointStateProbs;
+ int firstNumStates;
+ int secondNumStates;
+ int jointNumStates;
+ int i;
+ double length = vectorLength;
+ JointProbabilityState state;
+
+ firstNormalisedVector = (int *) CALLOC_FUNC(vectorLength,sizeof(int));
+ secondNormalisedVector = (int *) CALLOC_FUNC(vectorLength,sizeof(int));
+
+ firstNumStates = normaliseArray(firstVector,firstNormalisedVector,vectorLength);
+ secondNumStates = normaliseArray(secondVector,secondNormalisedVector,vectorLength);
+ jointNumStates = firstNumStates * secondNumStates;
+
+ firstStateCounts = (int *) CALLOC_FUNC(firstNumStates,sizeof(int));
+ secondStateCounts = (int *) CALLOC_FUNC(secondNumStates,sizeof(int));
+ jointStateCounts = (int *) CALLOC_FUNC(jointNumStates,sizeof(int));
+
+ firstStateProbs = (double *) CALLOC_FUNC(firstNumStates,sizeof(double));
+ secondStateProbs = (double *) CALLOC_FUNC(secondNumStates,sizeof(double));
+ jointStateProbs = (double *) CALLOC_FUNC(jointNumStates,sizeof(double));
+
+ /* optimised version, less numerically stable
+ double fractionalState = 1.0 / vectorLength;
+
+ for (i = 0; i < vectorLength; i++)
+ {
+ firstStateProbs[firstNormalisedVector[i]] += fractionalState;
+ secondStateProbs[secondNormalisedVector[i]] += fractionalState;
+ jointStateProbs[secondNormalisedVector[i] * firstNumStates + firstNormalisedVector[i]] += fractionalState;
+ }
+ */
+
+ /* Optimised for number of FP operations now O(states) instead of O(vectorLength) */
+ for (i = 0; i < vectorLength; i++)
+ {
+ firstStateCounts[firstNormalisedVector[i]] += 1;
+ secondStateCounts[secondNormalisedVector[i]] += 1;
+ jointStateCounts[secondNormalisedVector[i] * firstNumStates + firstNormalisedVector[i]] += 1;
+ }
+
+ for (i = 0; i < firstNumStates; i++)
+ {
+ firstStateProbs[i] = firstStateCounts[i] / length;
+ }
+
+ for (i = 0; i < secondNumStates; i++)
+ {
+ secondStateProbs[i] = secondStateCounts[i] / length;
+ }
+
+ for (i = 0; i < jointNumStates; i++)
+ {
+ jointStateProbs[i] = jointStateCounts[i] / length;
+ }
+
+ FREE_FUNC(firstNormalisedVector);
+ FREE_FUNC(secondNormalisedVector);
+ FREE_FUNC(firstStateCounts);
+ FREE_FUNC(secondStateCounts);
+ FREE_FUNC(jointStateCounts);
+
+ firstNormalisedVector = NULL;
+ secondNormalisedVector = NULL;
+ firstStateCounts = NULL;
+ secondStateCounts = NULL;
+ jointStateCounts = NULL;
+
+ /*
+ **typedef struct
+ **{
+ ** double *jointProbabilityVector;
+ ** int numJointStates;
+ ** double *firstProbabilityVector;
+ ** int numFirstStates;
+ ** double *secondProbabilityVector;
+ ** int numSecondStates;
+ **} JointProbabilityState;
+ */
+
+ state.jointProbabilityVector = jointStateProbs;
+ state.numJointStates = jointNumStates;
+ state.firstProbabilityVector = firstStateProbs;
+ state.numFirstStates = firstNumStates;
+ state.secondProbabilityVector = secondStateProbs;
+ state.numSecondStates = secondNumStates;
+
+ return state;
+}/*calculateJointProbability(double *,double *, int)*/
+
+ProbabilityState calculateProbability(double *dataVector, int vectorLength)
+{
+ int *normalisedVector;
+ int *stateCounts;
+ double *stateProbs;
+ int numStates;
+ /*double fractionalState;*/
+ ProbabilityState state;
+ int i;
+ double length = vectorLength;
+
+ normalisedVector = (int *) CALLOC_FUNC(vectorLength,sizeof(int));
+
+ numStates = normaliseArray(dataVector,normalisedVector,vectorLength);
+
+ stateCounts = (int *) CALLOC_FUNC(numStates,sizeof(int));
+ stateProbs = (double *) CALLOC_FUNC(numStates,sizeof(double));
+
+ /* optimised version, may have floating point problems
+ fractionalState = 1.0 / vectorLength;
+
+ for (i = 0; i < vectorLength; i++)
+ {
+ stateProbs[normalisedVector[i]] += fractionalState;
+ }
+ */
+
+ /* Optimised for number of FP operations now O(states) instead of O(vectorLength) */
+ for (i = 0; i < vectorLength; i++)
+ {
+ stateCounts[normalisedVector[i]] += 1;
+ }
+
+ for (i = 0; i < numStates; i++)
+ {
+ stateProbs[i] = stateCounts[i] / length;
+ }
+
+ FREE_FUNC(stateCounts);
+ FREE_FUNC(normalisedVector);
+
+ stateCounts = NULL;
+ normalisedVector = NULL;
+
+ state.probabilityVector = stateProbs;
+ state.numStates = numStates;
+
+ return state;
+}/*calculateProbability(double *,int)*/
+