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.conversion;
18  
19  import org.hipparchus.CalculusFieldElement;
20  import org.hipparchus.Field;
21  import org.hipparchus.exception.LocalizedCoreFormats;
22  import org.hipparchus.exception.MathIllegalArgumentException;
23  
24  /**
25   * Abstract class for integrator builder using fixed step size.
26   *
27   * @param <T> Type of the field elements
28   *
29   * @author Vincent Cucchietti
30   */
31  public abstract class AbstractFixedStepFieldIntegratorBuilder<T extends CalculusFieldElement<T>>
32          extends AbstractFieldIntegratorBuilder<T> {
33  
34      /** Step size (s). */
35      private double step;
36  
37      /** Step size (s). */
38      private T fieldStep;
39  
40      /**
41       * Constructor.
42       *
43       * @param step step size (s)
44       */
45      AbstractFixedStepFieldIntegratorBuilder(final double step) {
46          // Check that given step size is strictly positive
47          checkStep(step);
48  
49          this.step = step;
50      }
51  
52      /**
53       * Constructor using a "fielded" step.
54       * <p>
55       * <b>WARNING : Given "fielded" step must be using the same field as the one that will be used when calling
56       * {@link #buildIntegrator}</b>
57       *
58       * @param step step size (s)
59       */
60      AbstractFixedStepFieldIntegratorBuilder(final T step) {
61          // Check that given step size is strictly positive
62          checkStep(step.getReal());
63  
64          this.fieldStep = step;
65      }
66  
67      /**
68       * Check that given step size is not equal to 0.
69       *
70       * @param stepToCheck step size (s) to check
71       */
72      protected void checkStep(final double stepToCheck) {
73          if (stepToCheck == 0) {
74              throw new MathIllegalArgumentException(LocalizedCoreFormats.ZERO_NOT_ALLOWED, stepToCheck);
75          }
76      }
77  
78      /**
79       * Get "fielded" step size (s).
80       *
81       * @param field field to which the element belong
82       *
83       * @return "fielded" step size (s)
84       */
85      protected T getFieldStep(final Field<T> field) {
86          return fieldStep != null ? fieldStep : field.getZero().newInstance(step);
87      }
88  }