1   /* Copyright 2002-2022 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.propagation.SpacecraftState;
20  import org.orekit.utils.ParameterDriversList;
21  
22  /** Mapper between two-dimensional Jacobian matrices and one-dimensional {@link
23   * SpacecraftState#getAdditionalState(String) additional state arrays}.
24   * <p>
25   * This class does not hold the states by itself. Instances of this class are guaranteed
26   * to be immutable.
27   * </p>
28   * @author Vincent Mouraux
29   * @see org.orekit.propagation.numerical.NumericalPropagator
30   * @see SpacecraftState#getAdditionalState(String)
31   * @see org.orekit.propagation.AbstractPropagator
32   * @since 10.2
33   */
34  public class AbsoluteJacobiansMapper extends JacobiansMapper {
35  
36      /** State dimension, fixed to 6. */
37      public static final int STATE_DIMENSION = 6;
38  
39      /** Simple constructor.
40       * @param name name of the State Transition Matrix additional state
41       * @param parameters selected parameters for Jacobian computation
42       */
43      public AbsoluteJacobiansMapper(final String name, final ParameterDriversList parameters) {
44          // orbit type and angle type are not used here
45          super(name, parameters, null, null);
46      }
47  
48      /** {@inheritDoc} */
49      @Override
50      protected double[][] getConversionJacobian(final SpacecraftState state) {
51  
52          final double[][] identity = new double[STATE_DIMENSION][STATE_DIMENSION];
53  
54          for (int i = 0; i < STATE_DIMENSION; ++i) {
55              identity[i][i] = 1.0;
56          }
57  
58          return identity;
59  
60      }
61  
62  }