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  package org.orekit.propagation.sampling;
18  
19  import org.hipparchus.CalculusFieldElement;
20  import org.orekit.frames.Frame;
21  import org.orekit.propagation.FieldSpacecraftState;
22  import org.orekit.time.FieldAbsoluteDate;
23  import org.orekit.utils.FieldPVCoordinatesProvider;
24  import org.orekit.utils.TimeStampedFieldPVCoordinates;
25  
26  /** This interface is a space-dynamics aware step interpolator.
27   *
28   * <p>It mirrors the <code>StepInterpolator</code> interface from <a
29   * href="http://commons.apache.org/math/"> commons-math</a> but
30   * provides a space-dynamics interface to the methods.</p>
31   * @author Luc Maisonobe
32   * @param <T> type of the field elements
33   */
34  public interface FieldOrekitStepInterpolator<T extends CalculusFieldElement<T>> extends FieldPVCoordinatesProvider<T> {
35  
36      /**
37       * Get the state at previous grid point date.
38       * @return state at previous grid point date
39       */
40      FieldSpacecraftState<T> getPreviousState();
41  
42      /**
43       * Get the state at previous grid point date.
44       * @return state at previous grid point date
45       */
46      FieldSpacecraftState<T> getCurrentState();
47  
48      /** Get the state at interpolated date.
49       * @param date date of the interpolated state
50       * @return state at interpolated date
51            * the date
52       */
53      FieldSpacecraftState<T> getInterpolatedState(FieldAbsoluteDate<T> date);
54  
55      /** Check is integration direction is forward in date.
56       * @return true if integration is forward in date
57       */
58      boolean isForward();
59  
60      /** Create a new restricted version of the instance.
61       * <p>
62       * The instance is not changed at all.
63       * </p>
64       * @param newPreviousState start of the restricted step
65       * @param newCurrentState end of the restricted step
66       * @return restricted version of the instance
67       * @see #getPreviousState()
68       * @see #getCurrentState()
69       * @since 11.0
70       */
71      FieldOrekitStepInterpolator<T> restrictStep(FieldSpacecraftState<T> newPreviousState, FieldSpacecraftState<T> newCurrentState);
72  
73      /** {@inheritDoc}
74       * @since 12.0
75       */
76      @Override
77      default TimeStampedFieldPVCoordinates<T> getPVCoordinates(final FieldAbsoluteDate<T> date, final Frame frame) {
78          return getInterpolatedState(date).getPVCoordinates(frame);
79      }
80  
81  }