261 lines
9.2 KiB
Plaintext
261 lines
9.2 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {
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"slideshow": {
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"slide_type": "-"
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}
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},
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"source": [
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"### Uczenie maszynowe — zastosowania\n",
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"# Sieci neuronowe (Keras)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"[Keras](https://keras.io) to napisany w języku Python interfejs do platformy [TensorFlow](https://www.tensorflow.org), służącej do uczenia maszynowego.\n",
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"\n",
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"Aby z niego korzystać, trzeba zainstalować bibliotekę TensorFlow.\n",
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"\n",
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"Instrukcja dla skryptów Pythona (pliki *.py*):\n",
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" * `pip`: https://www.tensorflow.org/install\n",
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" * `conda`: https://docs.anaconda.com/anaconda/user-guide/tasks/tensorflow"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Aby uruchomić TensorFlow w środowisku Jupyter, należy wykonać następujące czynności:\n",
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"\n",
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"#### Przed pierwszym uruchomieniem (wystarczy wykonać tylko raz)\n",
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"\n",
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"Instalacja biblioteki TensorFlow w środowisku Anaconda:\n",
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"\n",
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"1. Uruchom *Anaconda Navigator*\n",
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"1. Wybierz kafelek *CMD.exe Prompt*\n",
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"1. Kliknij przycisk *Launch*\n",
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"1. Pojawi się konsola. Wpisz następujące polecenia, każde zatwierdzając wciśnięciem klawisza Enter:\n",
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"```\n",
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"conda create -n tf tensorflow\n",
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"conda activate tf\n",
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"conda install pandas matplotlib\n",
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"jupyter notebook\n",
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"```\n",
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"\n",
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"#### Przed każdym uruchomieniem\n",
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"\n",
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"Jeżeli chcemy korzystać z biblioteki TensorFlow, to środowisko Jupyter Notebook należy uruchomić w następujący sposób:\n",
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"\n",
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"1. Uruchom *Anaconda Navigator*\n",
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"1. Wybierz kafelek *CMD.exe Prompt*\n",
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"1. Kliknij przycisk *Launch*\n",
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"1. Pojawi się konsola. Wpisz następujące polecenia, każde zatwierdzając wciśnięciem klawisza Enter:\n",
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"```\n",
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"conda activate tf\n",
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"jupyter notebook\n",
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"```"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Przykład implementacji sieci neuronowej do rozpoznawania cyfr ze zbioru [MNIST](https://en.wikipedia.org/wiki/MNIST_database), według https://keras.io/examples/vision/mnist_convnet"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 4,
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"metadata": {},
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"outputs": [],
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"source": [
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"# Konieczne importy\n",
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"\n",
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"import numpy as np\n",
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"from tensorflow import keras\n",
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"from tensorflow.keras import layers"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {},
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"outputs": [
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{
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"ename": "NameError",
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"evalue": "name 'keras' is not defined",
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"output_type": "error",
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"traceback": [
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"\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
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"\u001b[1;31mNameError\u001b[0m Traceback (most recent call last)",
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"\u001b[1;32m<ipython-input-1-d9ae37c68de4>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[0;32m 5\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 6\u001b[0m \u001b[1;31m# podział danych na zbiory uczący i testowy\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 7\u001b[1;33m \u001b[1;33m(\u001b[0m\u001b[0mx_train\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0my_train\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;33m(\u001b[0m\u001b[0mx_test\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0my_test\u001b[0m\u001b[1;33m)\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mkeras\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mdatasets\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mmnist\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mload_data\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m 8\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 9\u001b[0m \u001b[1;31m# skalowanie wartości pikseli do przedziału [0, 1]\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
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"\u001b[1;31mNameError\u001b[0m: name 'keras' is not defined"
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]
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}
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],
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"source": [
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"# Przygotowanie danych\n",
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"\n",
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"num_classes = 10\n",
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"input_shape = (28, 28, 1)\n",
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"\n",
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"# podział danych na zbiory uczący i testowy\n",
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"(x_train, y_train), (x_test, y_test) = keras.datasets.mnist.load_data()\n",
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"\n",
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"# skalowanie wartości pikseli do przedziału [0, 1]\n",
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"x_train = x_train.astype(\"float32\") / 255\n",
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"x_test = x_test.astype(\"float32\") / 255\n",
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"# upewnienie się, że obrazy mają wymiary (28, 28, 1)\n",
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"x_train = np.expand_dims(x_train, -1)\n",
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"x_test = np.expand_dims(x_test, -1)\n",
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"print(\"x_train shape:\", x_train.shape)\n",
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"print(x_train.shape[0], \"train samples\")\n",
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"print(x_test.shape[0], \"test samples\")\n",
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"\n",
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"# konwersja danych kategorycznych na binarne\n",
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"y_train = keras.utils.to_categorical(y_train, num_classes)\n",
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"y_test = keras.utils.to_categorical(y_test, num_classes)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 6,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Model: \"sequential\"\n",
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"_________________________________________________________________\n",
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"Layer (type) Output Shape Param # \n",
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"=================================================================\n",
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"conv2d (Conv2D) (None, 26, 26, 32) 320 \n",
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"_________________________________________________________________\n",
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"max_pooling2d (MaxPooling2D) (None, 13, 13, 32) 0 \n",
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"_________________________________________________________________\n",
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"conv2d_1 (Conv2D) (None, 11, 11, 64) 18496 \n",
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"_________________________________________________________________\n",
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"max_pooling2d_1 (MaxPooling2 (None, 5, 5, 64) 0 \n",
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"_________________________________________________________________\n",
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"flatten (Flatten) (None, 1600) 0 \n",
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"_________________________________________________________________\n",
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"dropout (Dropout) (None, 1600) 0 \n",
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"_________________________________________________________________\n",
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"dense (Dense) (None, 10) 16010 \n",
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"=================================================================\n",
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"Total params: 34,826\n",
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"Trainable params: 34,826\n",
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"Non-trainable params: 0\n",
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"_________________________________________________________________\n"
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]
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}
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],
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"source": [
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"# Stworzenie modelu\n",
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"\n",
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"model = keras.Sequential(\n",
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" [\n",
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" keras.Input(shape=input_shape),\n",
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" layers.Conv2D(32, kernel_size=(3, 3), activation=\"relu\"),\n",
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" layers.MaxPooling2D(pool_size=(2, 2)),\n",
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" layers.Conv2D(64, kernel_size=(3, 3), activation=\"relu\"),\n",
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" layers.MaxPooling2D(pool_size=(2, 2)),\n",
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" layers.Flatten(),\n",
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" layers.Dropout(0.5),\n",
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" layers.Dense(num_classes, activation=\"softmax\"),\n",
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" ]\n",
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")\n",
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"\n",
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"model.summary()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 9,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"422/422 [==============================] - 38s 91ms/step - loss: 0.0556 - accuracy: 0.9826 - val_loss: 0.0412 - val_accuracy: 0.9893\n"
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]
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},
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{
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"data": {
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"text/plain": [
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"<tensorflow.python.keras.callbacks.History at 0x1a50b35a070>"
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]
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},
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"execution_count": 9,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"# Uczenie modelu\n",
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"\n",
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"batch_size = 128\n",
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"epochs = 15\n",
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"\n",
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"model.compile(loss=\"categorical_crossentropy\", optimizer=\"adam\", metrics=[\"accuracy\"])\n",
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"\n",
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"model.fit(x_train, y_train, epochs=1, batch_size=batch_size, epochs=epochs, validation_split=0.1)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 10,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Test loss: 0.03675819933414459\n",
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"Test accuracy: 0.988099992275238\n"
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]
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}
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],
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"source": [
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"# Ewaluacja modelu\n",
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"\n",
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"score = model.evaluate(x_test, y_test, verbose=0)\n",
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"print(\"Test loss:\", score[0])\n",
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"print(\"Test accuracy:\", score[1])"
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]
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}
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],
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"metadata": {
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"celltoolbar": "Slideshow",
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.8.3"
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},
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"livereveal": {
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"start_slideshow_at": "selected",
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"theme": "amu"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 4
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}
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