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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.geometry.partitioning;
18  
19  import org.hipparchus.geometry.Point;
20  import org.hipparchus.geometry.Space;
21  
22  /**
23   * Finder for interior points.
24   * @param <S> Type of the space.
25   * @param <P> Type of the points in space.
26   * @param <H> Type of the hyperplane.
27   * @param <I> Type of the sub-hyperplane.
28   * @since 4.0
29   */
30  public class InteriorPointFinder<S extends Space,
31                                   P extends Point<S, P>,
32                                   H extends Hyperplane<S, P, H, I>,
33                                   I extends SubHyperplane<S, P, H, I>>
34      implements BSPTreeVisitor<S, P, H, I> {
35  
36      /** Default point to use for whole space. */
37      private final P defaultPoint;
38  
39      /** Selected point. */
40      private BSPTree.InteriorPoint<S, P> selected;
41  
42      /**
43       * Simple constructor.
44       * @param defaultPoint default point to use for whole space
45       */
46      public InteriorPointFinder(final P defaultPoint) {
47          this.defaultPoint = defaultPoint;
48          this.selected     = null;
49      }
50  
51      /** {@inheritDoc} */
52      @Override
53      public Order visitOrder(final BSPTree<S, P, H, I> node) {
54          return Order.MINUS_PLUS_SUB;
55      }
56  
57      /** {@inheritDoc} */
58      @Override
59      public void visitInternalNode(final BSPTree<S, P, H, I> node) {
60          // nothing to do
61      }
62  
63      /** {@inheritDoc} */
64      @Override
65      public void visitLeafNode(final BSPTree<S, P, H, I> node) {
66          if ((Boolean) node.getAttribute()) {
67              // this is an inside cell, look for the barycenter of edges/facets interior points
68              final BSPTree.InteriorPoint<S, P> interior = node.getInteriorPoint(defaultPoint);
69              if (selected == null || interior.getDistance() > selected.getDistance()) {
70                  // this new point is farther away to edges/facets than the selected one, change selection
71                  selected = interior;
72              }
73          }
74      }
75  
76      /**
77       * Get the point found.
78       * @return found point (null if tree was empty)
79       */
80      public BSPTree.InteriorPoint<S, P> getPoint() {
81          return selected;
82      }
83  
84  }