| 1 | /* |
| 2 | * Copyright 2010 Savarese Software Research Corporation |
| 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 | * https://www.savarese.com/software/ApacheLicense-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 | |
| 17 | package com.savarese.spatial; |
| 18 | |
| 19 | /** |
| 20 | * The EuclideanDistance class determines the distance between two |
| 21 | * points in a Euclidean space. |
| 22 | */ |
| 23 | public class EuclideanDistance<Coord extends Number & Comparable<? super Coord>, |
| 24 | P extends Point<Coord>> |
| 25 | implements Distance<Coord, P> |
| 26 | { |
| 27 | /** |
| 28 | * Returns the euclidean distance between two points. |
| 29 | * |
| 30 | * @param from The first end point. |
| 31 | * @param to The second end point. |
| 32 | * @return The distance between from and to. |
| 33 | */ |
| 34 | public double distance(P from, P to) { |
| 35 | return StrictMath.sqrt(distance2(from, to)); |
| 36 | } |
| 37 | |
| 38 | /** |
| 39 | * Returns the square of the euclidean distance between two points. |
| 40 | * |
| 41 | * @param from The first end point. |
| 42 | * @param to The second end point. |
| 43 | * @return The square of the euclidean distance between from and to. |
| 44 | */ |
| 45 | public double distance2(P from, P to) { |
| 46 | double d = 0; |
| 47 | final int imax = from.getDimensions(); |
| 48 | |
| 49 | for(int i = 0; i < imax; ++i) { |
| 50 | double diff = (to.getCoord(i).doubleValue() - |
| 51 | from.getCoord(i).doubleValue()); |
| 52 | d+=(diff*diff); |
| 53 | } |
| 54 | |
| 55 | return d; |
| 56 | } |
| 57 | } |
