1 /*
2 * Copyright (C) 2015 Alberto Irurueta Carro (alberto@irurueta.com)
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package com.irurueta.numerical.fitting;
17
18 import com.irurueta.numerical.EvaluationException;
19
20 /**
21 * Interface to evaluate non-linear single dimensional functions.
22 * Evaluation of functions requires both function value at provided point x and
23 * function gradient respect to its parameters (i.e. derivatives respect to its
24 * parameters)
25 */
26 public interface LevenbergMarquardtSingleDimensionFunctionEvaluator {
27
28 /**
29 * Creates array where estimated parameters will be stored.
30 * This array MUST contain the initial guessed solution for the Levenberg-
31 * Marquardt algorithm
32 *
33 * @return array where estimated parameters will be stored
34 */
35 double[] createInitialParametersArray();
36
37 /**
38 * Evaluates a non-linear single dimension function at provided point using
39 * provided parameters and returns its evaluation and derivatives of the
40 * function respect the function parameters
41 *
42 * @param i number of sample being evaluated
43 * @param point point where function is evaluated
44 * @param params initial parameters estimation to be tried. These will
45 * change as the Levenberg-Marquard algorithm iterates to the best solution.
46 * These are used as input parameters along with point to evaluate function
47 * @param derivatives partial derivatives of the function respect to each
48 * provided parameter
49 * @return function evaluation at provided point and using provided
50 * parameters
51 * @throws EvaluationException raised if something failed during the evaluation
52 */
53 double evaluate(final int i, final double point, final double[] params, final double[] derivatives)
54 throws EvaluationException;
55 }