1 /* Copyright 2002-2021 CS GROUP
2 * Licensed to CS GROUP (CS) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * CS licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.orekit.propagation.numerical;
18
19 import org.orekit.errors.OrekitException;
20 import org.orekit.errors.OrekitMessages;
21 import org.orekit.forces.ForceModel;
22 import org.orekit.propagation.SpacecraftState;
23 import org.orekit.propagation.integration.AdditionalEquations;
24 import org.orekit.utils.ParameterDriver;
25
26 /** Set of {@link AdditionalEquations additional equations} computing the partial derivatives
27 * of the state (orbit) with respect to initial state and force models parameters.
28 * <p>
29 * This set of equations are automatically added to a {@link NumericalPropagator numerical propagator}
30 * in order to compute partial derivatives of the orbit along with the orbit itself. This is
31 * useful for example in orbit determination applications.
32 * </p>
33 * <p>
34 * The partial derivatives with respect to initial state can be either dimension 6
35 * (orbit only) or 7 (orbit and mass).
36 * </p>
37 * <p>
38 * The partial derivatives with respect to force models parameters has a dimension
39 * equal to the number of selected parameters. Parameters selection is implemented at
40 * {@link ForceModel force models} level. Users must retrieve a {@link ParameterDriver
41 * parameter driver} using {@link ForceModel#getParameterDriver(String)} and then
42 * select it by calling {@link ParameterDriver#setSelected(boolean) setSelected(true)}.
43 * </p>
44 * <p>
45 * If several force models provide different {@link ParameterDriver drivers} for the
46 * same parameter name, selecting any of these drivers has the side effect of
47 * selecting all the drivers for this shared parameter. In this case, the partial
48 * derivatives will be the sum of the partial derivatives contributed by the
49 * corresponding force models. This case typically arises for central attraction
50 * coefficient, which has an influence on {@link org.orekit.forces.gravity.NewtonianAttraction
51 * Newtonian attraction}, {@link org.orekit.forces.gravity.HolmesFeatherstoneAttractionModel
52 * gravity field}, and {@link org.orekit.forces.gravity.Relativity relativity}.
53 * </p>
54 * @author Vincent Mouraux
55 * @author Bryan Cazabonne
56 * @since 10.2
57 */
58 public class AbsolutePartialDerivativesEquations extends PartialDerivativesEquations {
59
60 /** Name. */
61 private final String name;
62
63 /** Simple constructor.
64 * <p>
65 * Upon construction, this set of equations is <em>automatically</em> added to
66 * the propagator by calling its {@link
67 * NumericalPropagator#addAdditionalEquations(AdditionalEquations)} method. So
68 * there is no need to call this method explicitly for these equations.
69 * </p>
70 * @param name name of the partial derivatives equations
71 * @param propagator the propagator that will handle the orbit propagation
72 */
73 public AbsolutePartialDerivativesEquations(final String name, final NumericalPropagator propagator) {
74 super(name, propagator);
75 this.name = name;
76 }
77
78 /** Get a mapper between two-dimensional Jacobians and one-dimensional additional state.
79 * @return a mapper between two-dimensional Jacobians and one-dimensional additional state,
80 * with the same name as the instance
81 * @see #setInitialJacobians(SpacecraftState)
82 * @see #setInitialJacobians(SpacecraftState, double[][], double[][])
83 */
84 @Override
85 public AbsoluteJacobiansMapper getMapper() {
86 if (!isInitialize()) {
87 throw new OrekitException(OrekitMessages.STATE_JACOBIAN_NOT_INITIALIZED);
88 }
89 return new AbsoluteJacobiansMapper(name, getSelectedParameters());
90 }
91
92 }
93