1   /* Copyright 2002-2024 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  
18  package org.orekit.files.ccsds.ndm.odm.ocm;
19  
20  import java.util.List;
21  
22  import org.hipparchus.linear.MatrixUtils;
23  import org.hipparchus.linear.RealMatrix;
24  import org.orekit.time.AbsoluteDate;
25  import org.orekit.time.TimeStamped;
26  import org.orekit.utils.units.Unit;
27  
28  /** Covariance entry.
29   * @author Luc Maisonobe
30   * @since 11.0
31   */
32  public class OrbitCovariance implements TimeStamped {
33  
34      /** Type of the elements. */
35      private final OrbitElementsType type;
36  
37      /** Entry date. */
38      private final AbsoluteDate date;
39  
40      /** Covariance matrix. */
41      private final RealMatrix matrix;
42  
43      /** Simple constructor.
44       * @param type type of the elements
45       * @param ordering ordering to use
46       * @param date entry date
47       * @param fields matrix elements
48       * @param first index of first field to consider
49       */
50      public OrbitCovariance(final OrbitElementsType type, final Ordering ordering, final AbsoluteDate date,
51                             final String[] fields, final int first) {
52          final List<Unit> units = type.getUnits();
53          this.type   = type;
54          this.date   = date;
55          this.matrix = MatrixUtils.createRealMatrix(units.size(), units.size());
56          final CovarianceIndexer indexer = new CovarianceIndexer(units.size());
57          for (int k = 0; first + k < fields.length; ++k) {
58              if (!indexer.isCrossCorrelation()) {
59                  final int    i         = indexer.getRow();
60                  final int    j         = indexer.getColumn();
61                  final double raw       = Double.parseDouble(fields[first + k]);
62                  final double converted = units.get(i).toSI(units.get(j).toSI(raw));
63                  matrix.setEntry(i, j, converted);
64                  if (i != j) {
65                      matrix.setEntry(j, i, converted);
66                  }
67              }
68              ordering.update(indexer);
69          }
70      }
71  
72      /** {@inheritDoc} */
73      @Override
74      public AbsoluteDate getDate() {
75          return date;
76      }
77  
78      /** Get the covariance matrix.
79       * @return covariance matrix
80       */
81      public RealMatrix getMatrix() {
82          return matrix;
83      }
84  
85      /** Get the type of the elements.
86       * @return type of the elements
87       */
88      public OrbitElementsType getType() {
89          return type;
90      }
91  
92  }