1   /* Copyright 2002-2020 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.semianalytical.dsst.utilities;
18  
19  /**  Interface for interpolation grids.
20   * <p>
21   * An interpolation grid provides a grid of time points
22   * that can be used for interpolation processes.
23   * </p><p>
24   * In the context of DSST propagation, an interpolation grid is used for the
25   * computation through interpolation of short periodics coefficients
26   * <p>
27   * @author Nicolas Bernard
28   */
29  public interface InterpolationGrid {
30  
31      /** Get grid points that are within the current step.
32       * <p>The step is defined by its start and its end time.
33       * </p>
34       * @param stepStart start of the step
35       * @param stepEnd end of the step
36       * @return time points between start and end
37       */
38      double[] getGridPoints(double stepStart, double stepEnd);
39  }