1   /* Copyright 2002-2025 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.utils;
18  
19  import org.orekit.time.AbsoluteDate;
20  
21  /** Interface representing a scalar function depending on a {@link ParameterDriver}.
22   * @see Differentiation#differentiate(ParameterFunction, int, double)
23   * @author Luc Maisonobe
24   * @since 8.0
25   */
26  @FunctionalInterface
27  public interface ParameterFunction {
28  
29  
30      /** Evaluate the function.
31       * @param parameterDriver driver for the parameter.
32       * @param date date at which the function wants to be known
33       * @return scalar value of the function
34       */
35      double value(ParameterDriver parameterDriver, AbsoluteDate date);
36  
37  }