/*******************************************************************************
* Copyright 2013 Analog Devices, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
********************************************************************************/
package com.analog.lyric.dimple.solvers.gibbs.customFactors;
import static java.util.Objects.*;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.eclipse.jdt.annotation.Nullable;
import com.analog.lyric.dimple.exceptions.DimpleException;
import com.analog.lyric.dimple.factorfunctions.DiscreteTransitionEnergyParameters;
import com.analog.lyric.dimple.factorfunctions.DiscreteTransitionUnnormalizedParameters;
import com.analog.lyric.dimple.factorfunctions.core.FactorFunction;
import com.analog.lyric.dimple.model.core.EdgeState;
import com.analog.lyric.dimple.model.factors.Factor;
import com.analog.lyric.dimple.model.variables.Discrete;
import com.analog.lyric.dimple.model.variables.Variable;
import com.analog.lyric.dimple.solvers.core.parameterizedMessages.GammaParameters;
import com.analog.lyric.dimple.solvers.gibbs.GibbsDiscrete;
import com.analog.lyric.dimple.solvers.gibbs.GibbsGammaEdge;
import com.analog.lyric.dimple.solvers.gibbs.GibbsRealFactor;
import com.analog.lyric.dimple.solvers.gibbs.GibbsSolverEdge;
import com.analog.lyric.dimple.solvers.gibbs.GibbsSolverGraph;
import com.analog.lyric.dimple.solvers.gibbs.samplers.conjugate.GammaSampler;
import com.analog.lyric.dimple.solvers.gibbs.samplers.conjugate.IRealConjugateSamplerFactory;
import com.analog.lyric.dimple.solvers.gibbs.samplers.conjugate.NegativeExpGammaSampler;
public class CustomDiscreteTransitionUnnormalizedOrEnergyParameters extends GibbsRealFactor implements IRealConjugateFactor
{
private @Nullable GibbsDiscrete _yVariable;
private @Nullable GibbsDiscrete _xVariable;
private boolean _hasConstantY;
private boolean _hasConstantX;
private boolean _useEnergyParameters;
private int _xDimension;
private int _yDimension;
private int _numParameters;
private int _numParameterEdges;
private int _startingParameterEdge;
private int _yPort = -1;
private int _xPort = -1;
private int _constantYValue;
private int _constantXValue;
private @Nullable int[] _parameterXIndices;
private @Nullable int[] _parameterYIndices;
private static final int NUM_DISCRETE_VARIABLES = 2;
private static final int Y_INDEX = 0;
private static final int X_INDEX = 1;
private static final int NO_PORT = -1;
public CustomDiscreteTransitionUnnormalizedOrEnergyParameters(Factor factor, GibbsSolverGraph parent)
{
super(factor, parent);
}
@Override
public @Nullable GibbsSolverEdge<?> createEdge(EdgeState edge)
{
if (edge.getFactorToVariableEdgeNumber() >= _startingParameterEdge)
{
return new GibbsGammaEdge();
}
return null;
}
@SuppressWarnings("null")
@Override
public void updateEdgeMessage(EdgeState modelEdge, GibbsSolverEdge<?> solverEdge)
{
final int portNum = modelEdge.getFactorToVariableEdgeNumber();
if (portNum >= _startingParameterEdge)
{
// Port is a parameter input
// Determine sample alpha and beta parameters
// NOTE: This class works for either DiscreteTransitionIndepenentParameters or DiscreteTransitionEnergyParameters factor functions
// since the actual parameter value doesn't come into play in determining the message in this direction
GammaParameters outputMsg = (GammaParameters)solverEdge.factorToVarMsg;
// Get the parameter coordinates
int parameterEdgeOffset = portNum - _startingParameterEdge;
int parameterXIndex = _parameterXIndices[parameterEdgeOffset];
int parameterYIndex = _parameterYIndices[parameterEdgeOffset];
// Get the sample values (indices of the discrete value, which corresponds to the value as well)
int xIndex = _hasConstantX ? _constantXValue : _xVariable.getCurrentSampleIndex();
int yIndex = _hasConstantY ? _constantYValue : _yVariable.getCurrentSampleIndex();
if (xIndex == parameterXIndex && yIndex == parameterYIndex)
{
// This edge corresponds to the current state, so count is 1
outputMsg.setAlphaMinusOne(1); // Sample alpha
outputMsg.setBeta(0); // Sample beta
}
else
{
// This edge does not correspond to the current state
outputMsg.setAlphaMinusOne(0); // Sample alpha
outputMsg.setBeta(0); // Sample beta
}
}
else
super.updateEdgeMessage(modelEdge, solverEdge);
}
@Override
public Set<IRealConjugateSamplerFactory> getAvailableRealConjugateSamplers(int portNumber)
{
Set<IRealConjugateSamplerFactory> availableSamplers = new HashSet<IRealConjugateSamplerFactory>();
if (isPortParameter(portNumber)) // Conjugate sampler if edge is a parameter input
if (_useEnergyParameters)
availableSamplers.add(NegativeExpGammaSampler.factory); // Parameter inputs have conjugate negative exp-Gamma distribution
else
availableSamplers.add(GammaSampler.factory); // Parameter inputs have conjugate Gamma distribution
return availableSamplers;
}
public boolean isPortParameter(int portNumber)
{
determineConstantsAndEdges(); // Call this here since initialize may not have been called yet
return (portNumber >= _startingParameterEdge);
}
@Override
public void initialize()
{
super.initialize();
// Determine what parameters are constants or edges, and save the state
determineConstantsAndEdges();
}
private void determineConstantsAndEdges()
{
final int prevStartingParameterEdge = _startingParameterEdge;
// Get the factor function and related state
final Factor factor = _model;
FactorFunction factorFunction = factor.getFactorFunction();
FactorFunction containedFactorFunction = factorFunction;
if (containedFactorFunction instanceof DiscreteTransitionUnnormalizedParameters)
{
DiscreteTransitionUnnormalizedParameters specificFactorFunction = (DiscreteTransitionUnnormalizedParameters)containedFactorFunction;
_xDimension = specificFactorFunction.getXDimension();
_yDimension = specificFactorFunction.getYDimension();
_numParameters = specificFactorFunction.getNumParameters();
_useEnergyParameters = false;
}
else if (containedFactorFunction instanceof DiscreteTransitionEnergyParameters)
{
DiscreteTransitionEnergyParameters specificFactorFunction = (DiscreteTransitionEnergyParameters)containedFactorFunction;
_xDimension = specificFactorFunction.getXDimension();
_yDimension = specificFactorFunction.getYDimension();
_numParameters = specificFactorFunction.getNumParameters();
_useEnergyParameters = true;
}
else
throw new DimpleException("Invalid factor function");
// Pre-determine whether or not the parameters are constant; if so save the value; if not save reference to the variable
_yPort = NO_PORT;
_xPort = NO_PORT;
_yVariable = null;
_xVariable = null;
_constantYValue = -1;
_constantXValue = -1;
_startingParameterEdge = 0;
List<? extends Variable> siblings = factor.getSiblings();
_hasConstantY = factor.hasConstantAtIndex(Y_INDEX);
if (_hasConstantY)
_constantYValue = requireNonNull(factor.getConstantValueByIndex(Y_INDEX)).getInt();
else // Variable Y
{
_yPort = factor.argIndexToSiblingNumber(Y_INDEX);
Discrete yVar = ((Discrete)siblings.get(_yPort));
_yVariable = (GibbsDiscrete)yVar.getSolver();
_yDimension = yVar.getDomain().size();
_startingParameterEdge++;
}
_hasConstantX = factor.hasConstantAtIndex(X_INDEX);
if (_hasConstantX)
_constantXValue = requireNonNull(factor.getConstantValueByIndex(X_INDEX)).getInt();
else // Variable X
{
_xPort = factor.argIndexToSiblingNumber(X_INDEX);
Discrete xVar = ((Discrete)siblings.get(_xPort));
_xVariable = (GibbsDiscrete)xVar.getSolver();
_startingParameterEdge++;
}
// Create a mapping between the edge connecting parameters and the XY coordinates in the parameter array
int numParameterConstants = factor.numConstantsAtOrAboveIndex(NUM_DISCRETE_VARIABLES);
_numParameterEdges = _numParameters - numParameterConstants;
final int[] parameterXIndices = _parameterXIndices = new int[_numParameterEdges];
final int[] parameterYIndices = _parameterYIndices = new int[_numParameterEdges];
if (numParameterConstants > 0)
{
int[] constantIndices = factor.getConstantIndices();
int constantIndex = 0;
int parameterEdgeOffset = 0;
for (int x = 0; x < _xDimension; x++) // Column scan order
{
for (int y = 0; y < _yDimension; y++)
{
int parameterOffset = x*_yDimension + y;
if (constantIndices[constantIndex] - NUM_DISCRETE_VARIABLES == parameterOffset)
{
// Parameter is constant
constantIndex++;
}
else
{
// Parameter is variable
parameterXIndices[parameterEdgeOffset] = x;
parameterYIndices[parameterEdgeOffset] = y;
parameterEdgeOffset++;
}
}
}
}
else // No constant parameters
{
for (int x = 0, parameterEdgeOffset = 0; x < _xDimension; x++) // Column scan order
{
for (int y = 0; y < _yDimension; y++, parameterEdgeOffset++)
{
parameterXIndices[parameterEdgeOffset] = x;
parameterYIndices[parameterEdgeOffset] = y;
}
}
}
if (_startingParameterEdge != prevStartingParameterEdge)
{
removeSiblingEdgeState();
}
}
}