AlgoCurvature.java

package org.geogebra.common.kernel.advanced;

import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.Kernel;
import org.geogebra.common.kernel.algos.AlgoElement;
import org.geogebra.common.kernel.commands.Commands;
import org.geogebra.common.kernel.geos.GeoElement;
import org.geogebra.common.kernel.geos.GeoFunction;
import org.geogebra.common.kernel.geos.GeoNumeric;
import org.geogebra.common.kernel.kernelND.GeoPointND;

/**
 * @author Victor Franco Espino, Markus Hohenwarter
 * @version 11-02-2007
 * 
 *          Calculate Curvature for function:
 */

public class AlgoCurvature extends AlgoElement {

	private GeoPointND A; // input
	private GeoFunction f;
	private GeoNumeric K; // output

	public AlgoCurvature(Construction cons, String label, GeoPointND A,
			GeoFunction f) {
		this(cons, A, f);

		if (label != null) {
			K.setLabel(label);
		} else {
			// if we don't have a label we could try k
			K.setLabel("k");
		}
	}

	public AlgoCurvature(Construction cons, GeoPointND A, GeoFunction f) {
		super(cons);
		this.f = f;
		this.A = A;
		K = new GeoNumeric(cons);

		setInputOutput();
		compute();
	}

	@Override
	public Commands getClassName() {
		return Commands.Curvature;
	}

	// for AlgoElement
	@Override
	protected void setInputOutput() {
		input = new GeoElement[2];
		input[0] = A.toGeoElement();
		input[1] = f;

		super.setOutputLength(1);
		super.setOutput(0, K);
		setDependencies(); // done by AlgoElement
	}

	public GeoNumeric getResult() {
		return K;
	}

	@Override
	public final void compute() {
		if (f.isDefined() && Kernel.isZero(A.getInhomZ())) {
			K.setValue(f.evaluateCurvature(A.getInhomX()));
		} else {
			K.setUndefined();
		}
	}

	@Override
	public void remove() {
		if (removed) {
			return;
		}
		super.remove();
	}

}