1 /*
2 * Licensed to the Apache Software Foundation (ASF) 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 ASF 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
18 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22 package org.hipparchus.geometry.partitioning;
23
24 import org.hipparchus.geometry.Point;
25 import org.hipparchus.geometry.Space;
26
27 /** This interface represents an hyperplane of a space.
28
29 * <p>The most prominent place where hyperplane appears in space
30 * partitioning is as cutters. Each partitioning node in a {@link
31 * BSPTree BSP tree} has a cut {@link SubHyperplane sub-hyperplane}
32 * which is either an hyperplane or a part of an hyperplane. In an
33 * n-dimensions euclidean space, an hyperplane is an (n-1)-dimensions
34 * hyperplane (for example a traditional plane in the 3D euclidean
35 * space). They can be more exotic objects in specific fields, for
36 * example a circle on the surface of the unit sphere.</p>
37
38 * <p>
39 * Note that this interface is <em>not</em> intended to be implemented
40 * by Hipparchus users, it is only intended to be implemented
41 * within the library itself. New methods may be added even for minor
42 * versions, which breaks compatibility for external implementations.
43 * </p>
44
45 * @param <S> Type of the space.
46 * @param <P> Type of the points in space.
47 * @param <H> Type of the hyperplane.
48 * @param <I> Type of the sub-hyperplane.
49
50 */
51 public interface Hyperplane<S extends Space,
52 P extends Point<S, P>,
53 H extends Hyperplane<S, P, H, I>,
54 I extends SubHyperplane<S, P, H, I>> {
55
56 /** Copy the instance.
57 * <p>The instance created is completely independent of the original
58 * one. A deep copy is used, none of the underlying objects are
59 * shared (except for immutable objects).</p>
60 * @return a new hyperplane, copy of the instance
61 */
62 H copySelf();
63
64 /** Get the offset (oriented distance) of a point.
65 * <p>The offset is 0 if the point is on the underlying hyperplane,
66 * it is positive if the point is on one particular side of the
67 * hyperplane, and it is negative if the point is on the other side,
68 * according to the hyperplane natural orientation.</p>
69 * @param point point to check
70 * @return offset of the point
71 */
72 double getOffset(P point);
73
74 /** Move point up to specified offset.
75 * <p>
76 * Motion is <em>orthogonal</em> to the hyperplane
77 * </p>
78 * @param point point to move
79 * @param offset desired offset
80 * @return moved point at desired offset
81 * @since 4.0
82 */
83 P moveToOffset(P point, double offset);
84
85 /** Get an arbitrary point in the hyperplane.
86 * @return arbirary point in the hyperplane
87 * @since 4.0
88 */
89 P arbitraryPoint();
90
91 /** Project a point to the hyperplane.
92 * @param point point to project
93 * @return projected point
94 */
95 P project(P point);
96
97 /** Get the tolerance below which points are considered to belong to the hyperplane.
98 * @return tolerance below which points are considered to belong to the hyperplane
99 */
100 double getTolerance();
101
102 /** Check if the instance has the same orientation as another hyperplane.
103 * <p>This method is expected to be called on parallel hyperplanes. The
104 * method should <em>not</em> re-check for parallelism, only for
105 * orientation, typically by testing something like the sign of the
106 * dot-products of normals.</p>
107 * @param other other hyperplane to check against the instance
108 * @return true if the instance and the other hyperplane have
109 * the same orientation
110 */
111 boolean sameOrientationAs(H other);
112
113 /** Build a sub-hyperplane covering the whole hyperplane.
114 * @return a sub-hyperplane covering the whole hyperplane
115 */
116 I wholeHyperplane();
117
118 /** Build a sub-hyperplane covering nothing.
119 * @return a sub-hyperplane covering nothing
120 * @since 1.4
121 */
122 I emptyHyperplane();
123
124 /** Build a region covering the whole space.
125 * @return a region containing the instance
126 */
127 Region<S, P, H, I> wholeSpace();
128
129 }