|
| 1 | +{ |
| 2 | + "cells": [ |
| 3 | + { |
| 4 | + "cell_type": "code", |
| 5 | + "execution_count": 23, |
| 6 | + "metadata": {}, |
| 7 | + "outputs": [], |
| 8 | + "source": [ |
| 9 | + "import numpy as np" |
| 10 | + ] |
| 11 | + }, |
| 12 | + { |
| 13 | + "cell_type": "code", |
| 14 | + "execution_count": 27, |
| 15 | + "metadata": {}, |
| 16 | + "outputs": [], |
| 17 | + "source": [ |
| 18 | + "def fit(X_train,Y_train):\n", |
| 19 | + " result = {}\n", |
| 20 | + " class_values = set(Y_train)\n", |
| 21 | + " for curr_value in class_values:\n", |
| 22 | + " result[curr_value] = {}\n", |
| 23 | + " result[\"total_data\"] = len(Y_train)\n", |
| 24 | + " curr_class_rows = (Y_train == curr_value)\n", |
| 25 | + " X_train_curr = X_train[curr_class_rows]\n", |
| 26 | + " Y_train_curr = Y_train[curr_class_rows]\n", |
| 27 | + " num_features = X_train.shape[1]\n", |
| 28 | + " result[curr_value][\"total_count\"] = len(Y_train_curr)\n", |
| 29 | + " for j in range(1,num_features+1):\n", |
| 30 | + " result[curr_value][j] = {}\n", |
| 31 | + " all_possible_values = set(X_train[:,j-1])\n", |
| 32 | + " for this_value in all_possible_values:\n", |
| 33 | + " result[curr_value][j][this_value] = (X_train_curr[:,j-1]==this_value).sum()\n", |
| 34 | + " return result" |
| 35 | + ] |
| 36 | + }, |
| 37 | + { |
| 38 | + "cell_type": "code", |
| 39 | + "execution_count": 28, |
| 40 | + "metadata": {}, |
| 41 | + "outputs": [], |
| 42 | + "source": [ |
| 43 | + "def probablity(dictionary,x,current_class):\n", |
| 44 | + " output= np.log(dictionary[current_class][\"total_count\"])-np.log(dictionary[\"total_data\"])\n", |
| 45 | + " num_features = len(dictionary[current_class].keys())-1;\n", |
| 46 | + " for j in range(1,num_features+1):\n", |
| 47 | + " xj = x[j-1]\n", |
| 48 | + " count_current_class_with_value_xj = dictionary[current_class][j][xj] + 1 \n", |
| 49 | + " count_current_class = dictionary[current_class][\"total_count\"] + len(dictionary[current_class][j].keys())\n", |
| 50 | + " current_xj_prob = np.log(count_current_class_with_value_xj) -np.log(count_current_class)\n", |
| 51 | + " output = output + current_xj_prob\n", |
| 52 | + " return output " |
| 53 | + ] |
| 54 | + }, |
| 55 | + { |
| 56 | + "cell_type": "code", |
| 57 | + "execution_count": 29, |
| 58 | + "metadata": {}, |
| 59 | + "outputs": [], |
| 60 | + "source": [ |
| 61 | + "def predictSinglePoint(dictionary,x):\n", |
| 62 | + " classes = dictionary.keys()\n", |
| 63 | + " best_p = -1000\n", |
| 64 | + " best_class = -1\n", |
| 65 | + " first_run = True\n", |
| 66 | + " for current_class in classes:\n", |
| 67 | + " if(current_class == \"total_data\"):\n", |
| 68 | + " continue\n", |
| 69 | + " p_curr_class = probablity(dictionary,x,current_class)\n", |
| 70 | + " if(first_run or p_curr_class > best_p):\n", |
| 71 | + " best_p = p_curr_class\n", |
| 72 | + " best_class = current_class\n", |
| 73 | + " first_run = False\n", |
| 74 | + " return best_class" |
| 75 | + ] |
| 76 | + }, |
| 77 | + { |
| 78 | + "cell_type": "code", |
| 79 | + "execution_count": 30, |
| 80 | + "metadata": {}, |
| 81 | + "outputs": [], |
| 82 | + "source": [ |
| 83 | + "def predict(dictionary,X_test):\n", |
| 84 | + " Y_pred = []\n", |
| 85 | + " for x in X_test:\n", |
| 86 | + " x_class = predictSinglePoint(dictionary,x)\n", |
| 87 | + " Y_pred.append(x_class)\n", |
| 88 | + " return Y_pred" |
| 89 | + ] |
| 90 | + }, |
| 91 | + { |
| 92 | + "cell_type": "code", |
| 93 | + "execution_count": 31, |
| 94 | + "metadata": {}, |
| 95 | + "outputs": [], |
| 96 | + "source": [ |
| 97 | + "def makelabelled(column):\n", |
| 98 | + " second_limit = column.mean()\n", |
| 99 | + " first_limit = 0.5 * second_limit\n", |
| 100 | + " third_limit = 1.5 * second_limit\n", |
| 101 | + " for i in range(0,len(column)):\n", |
| 102 | + " if(column[i]<first_limit):\n", |
| 103 | + " column[i] = 0\n", |
| 104 | + " elif(column[i] < second_limit):\n", |
| 105 | + " column[i] = 1\n", |
| 106 | + " elif(column[i]<third_limit):\n", |
| 107 | + " column[i] = 2\n", |
| 108 | + " else:\n", |
| 109 | + " column[i] = 3\n", |
| 110 | + " return column" |
| 111 | + ] |
| 112 | + }, |
| 113 | + { |
| 114 | + "cell_type": "code", |
| 115 | + "execution_count": 32, |
| 116 | + "metadata": {}, |
| 117 | + "outputs": [], |
| 118 | + "source": [ |
| 119 | + "from sklearn import datasets\n", |
| 120 | + "iris = datasets.load_iris()\n", |
| 121 | + "x = iris.data\n", |
| 122 | + "y = iris.target" |
| 123 | + ] |
| 124 | + }, |
| 125 | + { |
| 126 | + "cell_type": "code", |
| 127 | + "execution_count": 33, |
| 128 | + "metadata": {}, |
| 129 | + "outputs": [], |
| 130 | + "source": [ |
| 131 | + "for i in range(0,x.shape[-1]):\n", |
| 132 | + " x[:,i] = makelabelled(x[:,i])" |
| 133 | + ] |
| 134 | + }, |
| 135 | + { |
| 136 | + "cell_type": "code", |
| 137 | + "execution_count": 34, |
| 138 | + "metadata": {}, |
| 139 | + "outputs": [], |
| 140 | + "source": [ |
| 141 | + "from sklearn import model_selection\n", |
| 142 | + "X_train,X_test,Y_train,Y_test = model_selection.train_test_split(x,y,test_size=0.25,random_state=0)" |
| 143 | + ] |
| 144 | + }, |
| 145 | + { |
| 146 | + "cell_type": "code", |
| 147 | + "execution_count": 35, |
| 148 | + "metadata": {}, |
| 149 | + "outputs": [], |
| 150 | + "source": [ |
| 151 | + "dictionary = fit(X_train,Y_train)" |
| 152 | + ] |
| 153 | + }, |
| 154 | + { |
| 155 | + "cell_type": "code", |
| 156 | + "execution_count": 36, |
| 157 | + "metadata": {}, |
| 158 | + "outputs": [], |
| 159 | + "source": [ |
| 160 | + "Y_pred = predict(dictionary,X_test)" |
| 161 | + ] |
| 162 | + }, |
| 163 | + { |
| 164 | + "cell_type": "code", |
| 165 | + "execution_count": 37, |
| 166 | + "metadata": {}, |
| 167 | + "outputs": [ |
| 168 | + { |
| 169 | + "name": "stdout", |
| 170 | + "output_type": "stream", |
| 171 | + "text": [ |
| 172 | + " precision recall f1-score support\n", |
| 173 | + "\n", |
| 174 | + " 0 1.00 1.00 1.00 13\n", |
| 175 | + " 1 0.94 1.00 0.97 16\n", |
| 176 | + " 2 1.00 0.89 0.94 9\n", |
| 177 | + "\n", |
| 178 | + "avg / total 0.98 0.97 0.97 38\n", |
| 179 | + "\n", |
| 180 | + "[[13 0 0]\n", |
| 181 | + " [ 0 16 0]\n", |
| 182 | + " [ 0 1 8]]\n" |
| 183 | + ] |
| 184 | + } |
| 185 | + ], |
| 186 | + "source": [ |
| 187 | + "from sklearn.metrics import classification_report,confusion_matrix\n", |
| 188 | + "print(classification_report(Y_test,Y_pred))\n", |
| 189 | + "print(confusion_matrix(Y_test,Y_pred))" |
| 190 | + ] |
| 191 | + }, |
| 192 | + { |
| 193 | + "cell_type": "markdown", |
| 194 | + "metadata": {}, |
| 195 | + "source": [ |
| 196 | + "### Implememtation of Multinomial Naive Bayes from Scratch" |
| 197 | + ] |
| 198 | + }, |
| 199 | + { |
| 200 | + "cell_type": "code", |
| 201 | + "execution_count": null, |
| 202 | + "metadata": {}, |
| 203 | + "outputs": [], |
| 204 | + "source": [] |
| 205 | + } |
| 206 | + ], |
| 207 | + "metadata": { |
| 208 | + "kernelspec": { |
| 209 | + "display_name": "Python 3", |
| 210 | + "language": "python", |
| 211 | + "name": "python3" |
| 212 | + }, |
| 213 | + "language_info": { |
| 214 | + "codemirror_mode": { |
| 215 | + "name": "ipython", |
| 216 | + "version": 3 |
| 217 | + }, |
| 218 | + "file_extension": ".py", |
| 219 | + "mimetype": "text/x-python", |
| 220 | + "name": "python", |
| 221 | + "nbconvert_exporter": "python", |
| 222 | + "pygments_lexer": "ipython3", |
| 223 | + "version": "3.6.4" |
| 224 | + } |
| 225 | + }, |
| 226 | + "nbformat": 4, |
| 227 | + "nbformat_minor": 2 |
| 228 | +} |
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