/*
* Encog(tm) Core v3.3 - Java Version
* http://www.heatonresearch.com/encog/
* https://github.com/encog/encog-java-core
* Copyright 2008-2014 Heaton Research, 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.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package org.encog.ml.prg.train.rewrite;
import junit.framework.Assert;
import junit.framework.TestCase;
import org.encog.ml.CalculateScore;
import org.encog.ml.ea.score.adjust.ComplexityAdjustedScore;
import org.encog.ml.ea.train.basic.TrainEA;
import org.encog.ml.prg.EncogProgram;
import org.encog.ml.prg.EncogProgramContext;
import org.encog.ml.prg.PrgCODEC;
import org.encog.ml.prg.expvalue.DivisionByZeroError;
import org.encog.ml.prg.extension.StandardExtensions;
import org.encog.ml.prg.opp.SubtreeCrossover;
import org.encog.ml.prg.opp.SubtreeMutation;
import org.encog.ml.prg.train.PrgPopulation;
import org.encog.ml.prg.train.ZeroEvalScoreFunction;
import org.encog.parse.expression.common.RenderCommonExpression;
public class TestRewriteAlgebraic extends TestCase {
public void eval(String start, String expect) {
EncogProgramContext context = new EncogProgramContext();
StandardExtensions.createNumericOperators(context);
PrgPopulation pop = new PrgPopulation(context,1);
CalculateScore score = new ZeroEvalScoreFunction();
TrainEA genetic = new TrainEA(pop, score);
genetic.setValidationMode(true);
genetic.setCODEC(new PrgCODEC());
genetic.addOperation(0.95, new SubtreeCrossover());
genetic.addOperation(0.05, new SubtreeMutation(context,4));
genetic.addScoreAdjuster(new ComplexityAdjustedScore());
genetic.getRules().addRewriteRule(new RewriteConstants());
genetic.getRules().addRewriteRule(new RewriteAlgebraic());
EncogProgram expression = new EncogProgram(context);
expression.compileExpression(start);
RenderCommonExpression render = new RenderCommonExpression();
genetic.getRules().rewrite(expression);
Assert.assertEquals(expect, render.render(expression));
}
public void testMinusZero() {
eval("x-0","x");
eval("0-0","0");
eval("10-0","10");
}
public void testZeroMul() {
eval("0*0","0");
eval("1*0","0");
eval("0*1","0");
}
public void testZeroDiv() {
try {
eval("0/0","(0/0)");
Assert.assertFalse(true);
} catch(DivisionByZeroError ex) {
// expected
}
eval("0/5","0");
eval("0/x","0");
}
public void testZeroPlus() {
eval("0+0","0");
eval("1+0","1");
eval("0+1","1");
eval("x+0","x");
}
public void testPowerZero() {
eval("0^x","0");
eval("0^0","1");
eval("x^0","1");
eval("1^0","1");
eval("-1^0","1");
eval("(x+y)^0","1");
eval("x+(x+y)^0","(x+1)");
}
public void testOnePower() {
eval("1^500","1");
eval("1^x","1");
eval("1^1","1");
}
public void testDoubleNegative() {
eval("--x","x");
//eval("-x","-(x)");
}
public void testMinusMinus() {
eval("x--3","(x+3)");
}
public void testPlusNeg() {
eval("x+-y","(x-y)");
eval("x+-1","(x-1)");
}
public void testVarOpVar() {
eval("x-x","0");
eval("x+x","(2*x)");
eval("x*x","(x^2)");
eval("x/x","1");
}
public void testMultiple() {
eval("((x+-((0-(x+x))))*x)","((x-(0-(2*x)))*x)");
}
}