/*******************************************************************************
* Copyright 2015 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.test.solvers.sumproduct;
import static com.analog.lyric.dimple.model.sugar.ModelSyntacticSugar.*;
import static org.junit.Assert.*;
import org.junit.Test;
import com.analog.lyric.dimple.factorfunctions.XorDelta;
import com.analog.lyric.dimple.model.core.FactorGraph;
import com.analog.lyric.dimple.model.sugar.ModelSyntacticSugar.CurrentModel;
import com.analog.lyric.dimple.model.variables.Bit;
import com.analog.lyric.dimple.options.BPOptions;
import com.analog.lyric.dimple.solvers.sumproduct.SumProductSolver;
import com.analog.lyric.dimple.test.DimpleTestBase;
/**
*
* @since 0.08
* @author Christopher Barber
*/
public class TestSumProduct extends DimpleTestBase
{
@Test
public void testDamping()
{
// Adapted from MATLAB testDamping.m
for (boolean before : new boolean[] { true, false })
{
FactorGraph fg = new FactorGraph();
try (CurrentModel model = using(fg))
{
double dampingVal = 0.0;
if (before)
{
dampingVal = .4;
fg.setOption(BPOptions.damping, dampingVal);
}
Bit a = bit("a"), b = bit("b");
fg.addFactor(new XorDelta(), a, b);
a.setInput(.8);
if (!before)
{
dampingVal = .7;
fg.setOption(BPOptions.damping, dampingVal);
}
fg.setSolverFactory(new SumProductSolver());
fg.solve();
double msg2xor = dampingVal * .5 + (1-dampingVal) * .8;
double msgFromXor = dampingVal * .5 + (1-dampingVal)*msg2xor;
assertEquals(msgFromXor, b.getBelief()[1], 1e-12);
}
}
}
}