/*******************************************************************************
*   Copyright 2014 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.core.parameterizedMessages;

import static org.junit.Assert.*;

import org.junit.Test;

import com.analog.lyric.dimple.factorfunctions.Gamma;
import com.analog.lyric.dimple.model.values.Value;
import com.analog.lyric.dimple.solvers.core.parameterizedMessages.GammaParameters;
import com.analog.lyric.util.test.SerializationTester;

/**
 * 
 * @since 0.06
 * @author Christopher Barber
 */
public class TestGammaParameters extends TestParameterizedMessage
{
	@Test
	public void test()
	{
		GammaParameters msg = new GammaParameters();
		assertInvariants(msg);
		assertEquals(0.0, msg.getAlphaMinusOne(), 0.0);
		assertEquals(0.0, msg.getBeta(), 0.0);
		
		msg.setAlpha(3.5);
		assertEquals(3.5, msg.getAlpha(), 0.0);
		msg.setBeta(2.75);
		assertEquals(2.75, msg.getBeta(), 0.0);
		assertInvariants(msg);
		
		msg.setAlphaMinusOne(2.0);
		assertEquals(3.0, msg.getAlpha(), 0.0);
		assertInvariants(msg);
		
		msg.setNull();
		assertEquals(0.0, msg.getAlphaMinusOne(), 0.0);
		assertEquals(0.0, msg.getBeta(), 0.0);
		Value value = Value.createReal(0.0);
		for (int i = 0; i < 10; ++i)
		{
			value.setDouble(testRand.nextDouble());
			assertEquals(0.0, msg.evalEnergy(value), 0.0);
		}
		
		msg.setUniform();
		assertEquals(0.0, msg.getAlphaMinusOne(), 0.0);
		assertEquals(0.0, msg.getBeta(), 0.0);
		
		msg = new GammaParameters(3.0, 3.0);
		assertEquals(3.0, msg.getAlphaMinusOne(), 0.0);
		assertEquals(3.0, msg.getBeta(), 0.0);
		assertInvariants(msg);
		
		GammaParameters msg2 = new GammaParameters(4.0, 4.0);
		assertFalse(msg.objectEquals(msg2));
		
		// Values computed by hand in MATLAB
		assertEquals(.02509966, msg.computeKLDivergence(msg2), 1e-7);
		assertEquals(.02055160, msg2.computeKLDivergence(msg), 1e-7);
	}
	
	private void assertInvariants(GammaParameters msg)
	{
		assertGenericInvariants(msg);
		
		assertEquals(msg.getAlpha() - 1, msg.getAlphaMinusOne(), 0.0);

		GammaParameters msg2 = msg.clone();
		assertNotSame(msg, msg2);
		assertEquals(msg.getAlpha(), msg2.getAlpha(), 0.0);
		assertEquals(msg.getBeta(), msg2.getBeta(), 0.0);

		GammaParameters msg3 = SerializationTester.clone(msg);
		assertEquals(msg.getAlpha(), msg3.getAlpha(), 0.0);
		assertEquals(msg.getBeta(), msg3.getBeta(), 0.0);
		
		if (msg.getBeta() > 0 )
		{
			Gamma function = new Gamma(msg.getAlpha(), msg.getBeta());
			Value value = Value.createReal(-1);
			
			assertEquals(Double.POSITIVE_INFINITY, msg.evalEnergy(value), 0.0);
			
			for (int i = 0; i < 10; ++i)
			{
				value.setDouble(testRand.nextDouble());
				assertEquals(function.evalEnergy(value), msg.evalEnergy(value) - msg.getNormalizationEnergy(), 1e-15);
			}
		}
	}

}