/*******************************************************************************
* 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.factorfunctions;
import static java.util.Objects.*;
import com.analog.lyric.dimple.factorfunctions.core.FactorFunction;
import com.analog.lyric.dimple.model.values.Value;
import com.analog.lyric.util.misc.Matlab;
/**
* Deterministic matrix-vector product. This is a deterministic directed factor
* (if smoothing is not enabled).
*
* The constructor has two arguments that specify the length of the input and output
* vectors, respectively.
*
* Optional smoothing may be applied, by providing a smoothing value in the
* constructor. If smoothing is enabled, the distribution is smoothed by
* exp(-difference^2/smoothing), where difference is the distance between the
* output value and the deterministic output value for the corresponding inputs.
*
* The variables are ordered as follows in the argument list:
*
* 1) Output vector (RealJoint)
* 2) Input matrix (outLength x inLength, scanned by columns [because MATLAB assumes this])
* 3) Input vector (RealJoint)
*
* @since 0.05
*/
public class MatrixRealJointVectorProduct extends FactorFunction
{
private int _inLength;
private int _outLength;
private double _beta = 0;
private boolean _smoothingSpecified = false;
@Matlab
public MatrixRealJointVectorProduct(int inLength, int outLength) {this(inLength, outLength, 0);}
public MatrixRealJointVectorProduct(int inLength, int outLength, double smoothing)
{
super();
_inLength = inLength;
_outLength = outLength;
if (smoothing > 0)
{
_beta = 1 / smoothing;
_smoothingSpecified = true;
}
}
@Override
public final double evalEnergy(Value[] arguments)
{
// Compute the expected output
final Value[] expectedResult = evalDeterministicToCopy(arguments);
// Compare the output to the expected output
final double[] outValue = arguments[0].getDoubleArray();
final double[] expectedOutValue = expectedResult[0].getDoubleArray();
final int outLength = _outLength;
double error = 0;
for (int i = 0; i < outLength; i++)
{
final double diff = outValue[i] - expectedOutValue[i];
error += diff*diff;
}
if (_smoothingSpecified)
return error*_beta;
else
return (error == 0) ? 0 : Double.POSITIVE_INFINITY;
}
@Override
public final boolean isDirected() {return true;}
@Override
public final int[] getDirectedToIndices() {return new int[]{0};}
@Override
public final boolean isDeterministicDirected() {return !_smoothingSpecified;}
@Override
public void evalDeterministic(Value[] arguments)
{
int argIndex = 0;
double[] outVector = arguments[argIndex++].getDoubleArray();
final int inLength = _inLength;
final int outLength = _outLength;
// How is the matrix passed?
if (arguments[argIndex].getObject() instanceof double[][])
{
// Constant matrix is passed as a single argument; get the matrix values
final double[][] matrix = (double[][])requireNonNull(arguments[argIndex++].getObject());
// Get the input vector values
final double[] inVector = arguments[argIndex++].getDoubleArray();
// Compute the output and replace the output values
for (int row = 0; row < outLength; row++)
{
double sum = 0;
final double[] rowValues = matrix[row];
for (int col = 0; col < inLength; col++)
sum += rowValues[col] * inVector[col];
outVector[row] = sum;
}
}
else
{
// Variable matrix is passed as individual elements
final int numMatrixElements = inLength * outLength;
// Get the input vector values
final double[] inVector = arguments[argIndex + numMatrixElements].getDoubleArray();
// Compute the output and replace the output values
for (int row = 0, rowOffset = argIndex; row < outLength; row++, rowOffset++)
{
double sum = 0;
for (int col = 0, offset = rowOffset; col < inLength; col++, offset += outLength)
sum += arguments[offset].getDouble() * inVector[col];
outVector[row] = sum;
}
}
}
}