FixedNumberInterpolationGrid.java

  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. /** Interpolation grid where a fixed number of points are
  19.  * evenly spaced between the start and the end of the integration step.
  20.  * <p>
  21.  * The grid is adapted to the step considered,
  22.  * meaning that for short steps, the grid will be dense,
  23.  * while for long steps the points will be far away one from each other
  24.  * </p>
  25.  *
  26.  * @author Nicolas Bernard
  27.  */
  28. public class FixedNumberInterpolationGrid implements InterpolationGrid {

  29.     /** Number of points in the grid per step. */
  30.     private final int pointsPerStep;

  31.     /** Constructor.
  32.      * @param pointsPerStep number of points in the grid per step
  33.      */
  34.     public FixedNumberInterpolationGrid(final int pointsPerStep) {
  35.         this.pointsPerStep = pointsPerStep;
  36.     }

  37.     /** {@inheritDoc} */
  38.     @Override
  39.     public double[] getGridPoints(final double stepStart, final double stepEnd) {
  40.         final double[] grid = new double[pointsPerStep];

  41.         final double stepSize = (stepEnd - stepStart) / (pointsPerStep - 1);
  42.         for (int i = 0; i < pointsPerStep; i++) {
  43.             grid[i] = stepSize * i + stepStart;
  44.         }

  45.         return grid;
  46.     }
  47. }