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 /** Interpolation grid where a fixed number of points are
20 * evenly spaced between the start and the end of the integration step.
21 * <p>
22 * The grid is adapted to the step considered,
23 * meaning that for short steps, the grid will be dense,
24 * while for long steps the points will be far away one from each other
25 * </p>
26 *
27 * @author Nicolas Bernard
28 */
29 public class FixedNumberInterpolationGrid implements InterpolationGrid {
30
31 /** Number of points in the grid per step. */
32 private final int pointsPerStep;
33
34 /** Constructor.
35 * @param pointsPerStep number of points in the grid per step
36 */
37 public FixedNumberInterpolationGrid(final int pointsPerStep) {
38 this.pointsPerStep = pointsPerStep;
39 }
40
41 /** {@inheritDoc} */
42 @Override
43 public double[] getGridPoints(final double stepStart, final double stepEnd) {
44 final double[] grid = new double[pointsPerStep];
45
46 final double stepSize = (stepEnd - stepStart) / (pointsPerStep - 1);
47 for (int i = 0; i < pointsPerStep; i++) {
48 grid[i] = stepSize * i + stepStart;
49 }
50
51 return grid;
52 }
53 }