1   /* Copyright 2022-2025 Luc Maisonobe
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.attitudes;
18  
19  import org.hipparchus.CalculusFieldElement;
20  import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
21  
22  
23  /** Container for inertial axis.
24   * <p>
25   * Instances of this class are immutable
26   * </p>
27   * @param <T> type fof the field elements
28   * @author Luc Maisonobe
29   * @since 12.0
30   */
31  public class FieldInertiaAxis<T extends CalculusFieldElement<T>> {
32  
33      /** Moment of inertia. */
34      private final T i;
35  
36      /** Inertia axis. */
37      private final FieldVector3D<T> a;
38  
39      /** Simple constructor to pair a moment of inertia with its associated axis.
40       * @param i moment of inertia
41       * @param a inertia axis
42       */
43      public FieldInertiaAxis(final T i, final FieldVector3D<T> a) {
44          this.i = i;
45          this.a = a;
46      }
47  
48      /** Reverse the inertia axis.
49       * @return new container with reversed axis
50       */
51      public FieldInertiaAxis<T> negate() {
52          return new FieldInertiaAxis<>(i, a.negate());
53      }
54  
55      /** Get the moment of inertia.
56       * @return moment of inertia
57       */
58      public T getI() {
59          return i;
60      }
61  
62      /** Get the inertia axis.
63       * @return inertia axis
64       */
65      public FieldVector3D<T> getA() {
66          return a;
67      }
68  
69  }