1 /*
2 * Licensed to the Hipparchus project under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The Hipparchus project 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 * https://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.hipparchus.analysis.integration.gauss;
18
19 import org.hipparchus.CalculusFieldElement;
20 import org.hipparchus.FieldElement;
21 import org.hipparchus.exception.MathIllegalArgumentException;
22 import org.hipparchus.util.Pair;
23
24 /**
25 * Factory converting {@link CalculusFieldElement field-based} {@link FieldRuleFactory} into {@link RuleFactory}.
26 * @param <T> Type of the number used to represent the points and weights of
27 * the quadrature rules.
28 * @since 2.0
29 */
30 public class ConvertingRuleFactory<T extends FieldElement<T>> extends AbstractRuleFactory {
31
32 /** Underlying field-based factory. */
33 private final FieldRuleFactory<T> fieldFactory;
34
35 /** Simple constructor.
36 * @param fieldFactory field-based factory to convert
37 */
38 public ConvertingRuleFactory(final FieldRuleFactory<T> fieldFactory) {
39 this.fieldFactory = fieldFactory;
40 }
41
42 /** {@inheritDoc} */
43 @Override
44 protected Pair<double[], double[]> computeRule(final int numberOfPoints)
45 throws MathIllegalArgumentException {
46
47 // get the field-based rule
48 Pair<T[], T[]> rule = fieldFactory.getRule(numberOfPoints);
49
50 // convert the nodes and weights
51 final T[] pT = rule.getFirst();
52 final T[] wT = rule.getSecond();
53
54 final int len = pT.length;
55 final double[] pD = new double[len];
56 final double[] wD = new double[len];
57
58 for (int i = 0; i < len; i++) {
59 pD[i] = pT[i].getReal();
60 wD[i] = wT[i].getReal();
61 }
62
63 return new Pair<>(pD, wD);
64
65 }
66
67 }