|
| 1 | +{ |
| 2 | + "cells": [ |
| 3 | + { |
| 4 | + "cell_type": "markdown", |
| 5 | + "metadata": { |
| 6 | + "nteract": { |
| 7 | + "transient": { |
| 8 | + "deleting": false |
| 9 | + } |
| 10 | + } |
| 11 | + }, |
| 12 | + "source": [ |
| 13 | + "### DistanceMetric\n", |
| 14 | + "\n", |
| 15 | + "This class provides a uniform interface to fast distance metric functions. The various metrics can be accessed via the get_metric class method and the metric string identifier" |
| 16 | + ] |
| 17 | + }, |
| 18 | + { |
| 19 | + "cell_type": "markdown", |
| 20 | + "metadata": { |
| 21 | + "nteract": { |
| 22 | + "transient": { |
| 23 | + "deleting": false |
| 24 | + } |
| 25 | + } |
| 26 | + }, |
| 27 | + "source": [ |
| 28 | + "**Available Metrics**\n", |
| 29 | + "\n", |
| 30 | + "The following lists the string metric identifiers and the associated distance metric classes:\n", |
| 31 | + "\n", |
| 32 | + "* Metrics intended for real-valued vector spaces:\n", |
| 33 | + "\n", |
| 34 | + "|**Identifier**|**Class name in scikit-learn**|**Args**|**Distance function**|\n", |
| 35 | + "|--------------|------------|------------|------------|\n", |
| 36 | + "|`Euclidean`|EuclideanDistance|.|$sqrt(sum((x - y)^2))$|\n", |
| 37 | + "|`Manhattan`|ManhattanDistance|.|$sum(x - y)$|\n", |
| 38 | + "|`chebyshev`|ChebyshevDistance|.|$max(x - y)$|\n", |
| 39 | + "|`minkowski`|MinkowskiDistance|p|$sum(x - y^p)^(1/p)$|\n", |
| 40 | + "|`wminkowski`|WMinkowskiDistance|p, w|$sum(w * (x - y)^p)^(1/p)$|\n", |
| 41 | + "|`seuclidean`|SEuclideanDistance|V|$sqrt(sum((x - y)^2 / V))$|\n", |
| 42 | + "|`mahalanobis`|MahalanobisDistance|V or VI|$sqrt((x - y)' V^-1 (x - y))$|\n", |
| 43 | + "\n", |
| 44 | + "\n", |
| 45 | + "\n", |
| 46 | + "**Metrics intended for two-dimensional vector spaces:**\n", |
| 47 | + "\n", |
| 48 | + "* Note that the haversine distance metric requires data in the form of [latitude, longitude] and both inputs and outputs are in units of radians.\n", |
| 49 | + "\n", |
| 50 | + "|**Identifier**|**Class name in scikit-learn**|**Distance function**|\n", |
| 51 | + "|--------------|------------|------------|------------|\n", |
| 52 | + "|`haversine`|HaversineDistance|$2 arcsin(sqrt(sin^2(0.5*dx) + cos(x1)cos(x2)sin^2(0.5*dy)))$|" |
| 53 | + ] |
| 54 | + }, |
| 55 | + { |
| 56 | + "cell_type": "code", |
| 57 | + "execution_count": 2, |
| 58 | + "metadata": { |
| 59 | + "nteract": { |
| 60 | + "transient": { |
| 61 | + "deleting": false |
| 62 | + } |
| 63 | + } |
| 64 | + }, |
| 65 | + "outputs": [ |
| 66 | + { |
| 67 | + "data": { |
| 68 | + "text/plain": [ |
| 69 | + "array([[0, 1, 2],\n", |
| 70 | + " [3, 4, 5]])" |
| 71 | + ] |
| 72 | + }, |
| 73 | + "execution_count": 2, |
| 74 | + "metadata": {}, |
| 75 | + "output_type": "execute_result" |
| 76 | + } |
| 77 | + ], |
| 78 | + "source": [ |
| 79 | + "from sklearn.neighbors import DistanceMetric\n", |
| 80 | + "import numpy as np\n", |
| 81 | + "\n", |
| 82 | + "euclidean_dist = DistanceMetric.get_metric('euclidean')\n", |
| 83 | + "X = np.array([[0, 1, 2],[3, 4, 5]])\n", |
| 84 | + "X" |
| 85 | + ] |
| 86 | + }, |
| 87 | + { |
| 88 | + "cell_type": "code", |
| 89 | + "execution_count": 3, |
| 90 | + "metadata": { |
| 91 | + "nteract": { |
| 92 | + "transient": { |
| 93 | + "deleting": false |
| 94 | + } |
| 95 | + } |
| 96 | + }, |
| 97 | + "outputs": [ |
| 98 | + { |
| 99 | + "data": { |
| 100 | + "text/plain": [ |
| 101 | + "array([[0. , 5.19615242],\n", |
| 102 | + " [5.19615242, 0. ]])" |
| 103 | + ] |
| 104 | + }, |
| 105 | + "execution_count": 3, |
| 106 | + "metadata": {}, |
| 107 | + "output_type": "execute_result" |
| 108 | + } |
| 109 | + ], |
| 110 | + "source": [ |
| 111 | + "euclidean_dist.pairwise(X)" |
| 112 | + ] |
| 113 | + }, |
| 114 | + { |
| 115 | + "cell_type": "code", |
| 116 | + "execution_count": 4, |
| 117 | + "metadata": { |
| 118 | + "nteract": { |
| 119 | + "transient": { |
| 120 | + "deleting": false |
| 121 | + } |
| 122 | + } |
| 123 | + }, |
| 124 | + "outputs": [], |
| 125 | + "source": [ |
| 126 | + "Manhattan_dist = DistanceMetric.get_metric('manhattan')" |
| 127 | + ] |
| 128 | + }, |
| 129 | + { |
| 130 | + "cell_type": "code", |
| 131 | + "execution_count": 5, |
| 132 | + "metadata": { |
| 133 | + "nteract": { |
| 134 | + "transient": { |
| 135 | + "deleting": false |
| 136 | + } |
| 137 | + } |
| 138 | + }, |
| 139 | + "outputs": [ |
| 140 | + { |
| 141 | + "data": { |
| 142 | + "text/plain": [ |
| 143 | + "array([[0., 9.],\n", |
| 144 | + " [9., 0.]])" |
| 145 | + ] |
| 146 | + }, |
| 147 | + "execution_count": 5, |
| 148 | + "metadata": {}, |
| 149 | + "output_type": "execute_result" |
| 150 | + } |
| 151 | + ], |
| 152 | + "source": [ |
| 153 | + "Manhattan_dist.pairwise(X)" |
| 154 | + ] |
| 155 | + }, |
| 156 | + { |
| 157 | + "cell_type": "code", |
| 158 | + "execution_count": 6, |
| 159 | + "metadata": { |
| 160 | + "nteract": { |
| 161 | + "transient": { |
| 162 | + "deleting": false |
| 163 | + } |
| 164 | + } |
| 165 | + }, |
| 166 | + "outputs": [], |
| 167 | + "source": [ |
| 168 | + "ChebyshevDistance = DistanceMetric.get_metric('chebyshev')" |
| 169 | + ] |
| 170 | + }, |
| 171 | + { |
| 172 | + "cell_type": "code", |
| 173 | + "execution_count": 7, |
| 174 | + "metadata": { |
| 175 | + "nteract": { |
| 176 | + "transient": { |
| 177 | + "deleting": false |
| 178 | + } |
| 179 | + } |
| 180 | + }, |
| 181 | + "outputs": [ |
| 182 | + { |
| 183 | + "data": { |
| 184 | + "text/plain": [ |
| 185 | + "array([[0., 3.],\n", |
| 186 | + " [3., 0.]])" |
| 187 | + ] |
| 188 | + }, |
| 189 | + "execution_count": 7, |
| 190 | + "metadata": {}, |
| 191 | + "output_type": "execute_result" |
| 192 | + } |
| 193 | + ], |
| 194 | + "source": [ |
| 195 | + "ChebyshevDistance.pairwise(X)" |
| 196 | + ] |
| 197 | + }, |
| 198 | + { |
| 199 | + "cell_type": "code", |
| 200 | + "execution_count": 8, |
| 201 | + "metadata": { |
| 202 | + "nteract": { |
| 203 | + "transient": { |
| 204 | + "deleting": false |
| 205 | + } |
| 206 | + } |
| 207 | + }, |
| 208 | + "outputs": [ |
| 209 | + { |
| 210 | + "data": { |
| 211 | + "text/plain": [ |
| 212 | + "array([[0. , 5.19615242],\n", |
| 213 | + " [5.19615242, 0. ]])" |
| 214 | + ] |
| 215 | + }, |
| 216 | + "execution_count": 8, |
| 217 | + "metadata": {}, |
| 218 | + "output_type": "execute_result" |
| 219 | + } |
| 220 | + ], |
| 221 | + "source": [ |
| 222 | + "MinkowskiDistance = DistanceMetric.get_metric('minkowski')\n", |
| 223 | + "MinkowskiDistance.pairwise(X)" |
| 224 | + ] |
| 225 | + }, |
| 226 | + { |
| 227 | + "cell_type": "code", |
| 228 | + "execution_count": 10, |
| 229 | + "metadata": { |
| 230 | + "nteract": { |
| 231 | + "transient": { |
| 232 | + "deleting": false |
| 233 | + } |
| 234 | + } |
| 235 | + }, |
| 236 | + "outputs": [ |
| 237 | + { |
| 238 | + "data": { |
| 239 | + "text/plain": [ |
| 240 | + "2.0" |
| 241 | + ] |
| 242 | + }, |
| 243 | + "execution_count": 10, |
| 244 | + "metadata": {}, |
| 245 | + "output_type": "execute_result" |
| 246 | + } |
| 247 | + ], |
| 248 | + "source": [ |
| 249 | + "from scipy.spatial import distance\n", |
| 250 | + "distance.wminkowski([1, 0, 0], [0, 1, 0], 1, np.ones(3))" |
| 251 | + ] |
| 252 | + } |
| 253 | + ], |
| 254 | + "metadata": { |
| 255 | + "kernel_info": { |
| 256 | + "name": "python3" |
| 257 | + }, |
| 258 | + "kernelspec": { |
| 259 | + "display_name": "Python 3", |
| 260 | + "language": "python", |
| 261 | + "name": "python3" |
| 262 | + }, |
| 263 | + "language_info": { |
| 264 | + "codemirror_mode": { |
| 265 | + "name": "ipython", |
| 266 | + "version": 3 |
| 267 | + }, |
| 268 | + "file_extension": ".py", |
| 269 | + "mimetype": "text/x-python", |
| 270 | + "name": "python", |
| 271 | + "nbconvert_exporter": "python", |
| 272 | + "pygments_lexer": "ipython3", |
| 273 | + "version": "3.6.8" |
| 274 | + }, |
| 275 | + "nteract": { |
| 276 | + "version": "0.24.0" |
| 277 | + } |
| 278 | + }, |
| 279 | + "nbformat": 4, |
| 280 | + "nbformat_minor": 4 |
| 281 | +} |
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