/*
* Created on 31-May-2007
*/
package ca.nengo.math.impl;
import ca.nengo.TestUtil;
import ca.nengo.math.Function;
//import ca.nengo.math.RootFinder;
import ca.nengo.math.impl.ConstantFunction;
import ca.nengo.math.impl.FourierFunction;
import ca.nengo.math.impl.IdentityFunction;
import ca.nengo.math.impl.NewtonRootFinder;
import ca.nengo.math.impl.PiecewiseConstantFunction;
import ca.nengo.math.impl.Polynomial;
import ca.nengo.math.impl.SigmoidFunction;
import ca.nengo.math.impl.SineFunction;
import junit.framework.TestCase;
public class NewtonRootFinderTest extends TestCase {
/**
* Test method for 'ca.nengo.math.impl.NewtonRootFinder.findRoot()'
*/
public void testFindRoot() {
float root = -1f;
NewtonRootFinder nrf = new NewtonRootFinder(20, false);
Function func = new ConstantFunction(1, 1f);
try {
root = nrf.findRoot(func, -5, 15, 0.0001f);
} catch (RuntimeException e) { // failure after too many attempts
}
func = new FourierFunction(new float[]{1, 0.5f, 1}, new float[]{1, 1, 0.5f}, new float[]{0, -0.5f, 0.2f});
root = nrf.findRoot(func, -5, 5, 0.0001f);
TestUtil.assertClose(func.map(new float[]{root}), 0, 0.001f);
func = new IdentityFunction(1, 0);
root = nrf.findRoot(func, -5, 5, 0.0001f);
TestUtil.assertClose(func.map(new float[]{root}), 0, 0.001f);
func = new PiecewiseConstantFunction(new float[]{-1,1}, new float[]{2,0,-2});
try {
root = nrf.findRoot(func, -5, 15, 0.0001f);
} catch (RuntimeException e) { // failure after too many attempts
}
func = new Polynomial(new float[]{4f, 2f, -3f, 1f});
root = nrf.findRoot(func, -5, 15, 0.0001f);
TestUtil.assertClose(func.map(new float[]{root}), 0, 0.001f);
func = new SigmoidFunction(-1f, 0.3f, -0.5f, 1f);
root = nrf.findRoot(func, -5, 5, 0.0001f);
TestUtil.assertClose(func.map(new float[]{root}), 0, 0.001f);
func = new SineFunction(0.5f);
root = nrf.findRoot(func, -5, 5, 0.0001f);
TestUtil.assertClose(func.map(new float[]{root}), 0, 0.001f);
}
}