AbstractBodyAttraction.java
/* Copyright 2022-2024 Romain Serra
* Licensed to CS GROUP (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You 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 org.orekit.forces.gravity;
import org.hipparchus.util.FastMath;
import org.orekit.bodies.CelestialBody;
import org.orekit.forces.ForceModel;
import org.orekit.utils.ParameterDriver;
import java.util.Collections;
import java.util.List;
/** Abstract class for body attraction force model.
*
* @author Romain Serra
*/
public abstract class AbstractBodyAttraction implements ForceModel {
/** Suffix for parameter name for attraction coefficient enabling Jacobian processing. */
public static final String ATTRACTION_COEFFICIENT_SUFFIX = " attraction coefficient";
/** Central attraction scaling factor.
* <p>
* We use a power of 2 to avoid numeric noise introduction
* in the multiplications/divisions sequences.
* </p>
*/
private static final double MU_SCALE = FastMath.scalb(1.0, 32);
/** The body to consider. */
private final CelestialBody body;
/** Drivers for body attraction coefficient. */
private final ParameterDriver gmParameterDriver;
/** Simple constructor.
* @param body the third body to consider
*/
protected AbstractBodyAttraction(final CelestialBody body) {
this.body = body;
this.gmParameterDriver = new ParameterDriver(body.getName() + ATTRACTION_COEFFICIENT_SUFFIX,
body.getGM(), MU_SCALE, 0.0, Double.POSITIVE_INFINITY);
}
/** Getter for the body's name.
* @return the body's name
*/
public String getBodyName() {
return body.getName();
}
/** Protected getter for the body.
* @return the third body considered
*/
protected CelestialBody getBody() {
return body;
}
/** {@inheritDoc} */
@Override
public boolean dependsOnPositionOnly() {
return true;
}
/** {@inheritDoc} */
@Override
public List<ParameterDriver> getParametersDrivers() {
return Collections.singletonList(gmParameterDriver);
}
}