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lab/7_Muticlass.ipynb
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327
lab/7_Muticlass.ipynb
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{
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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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"source": [
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"# 多分类问题 - 手写数字识别\n",
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"\n",
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"## 数据集\n",
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"- minst数据集(手写数字数据集)\n",
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"\n",
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"## 激活函数\n",
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"- softmax\n",
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"\n",
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"## 损失函数\n",
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"- 交叉熵\n",
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"\n",
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"## 优化器\n",
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"- 梯度下降\n",
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"\n",
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"## 模型\n",
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"- 全连接层\n"
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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": 7,
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"metadata": {},
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"outputs": [],
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"source": [
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"# 导库\n",
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"import tensorflow as tf\n",
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"from tensorflow.keras import Sequential\n",
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"from tensorflow.keras.layers import Dense\n",
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"from tensorflow.keras.losses import SparseCategoricalCrossentropy"
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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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"data": {
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"text/html": [
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"<pre style=\"white-space:pre;overflow-x:auto;line-height:normal;font-family:Menlo,'DejaVu Sans Mono',consolas,'Courier New',monospace\"><span style=\"font-weight: bold\">Model: \"sequential_2\"</span>\n",
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"</pre>\n"
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],
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"text/plain": [
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"\u001b[1mModel: \"sequential_2\"\u001b[0m\n"
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]
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},
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"metadata": {},
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"output_type": "display_data"
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},
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{
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"data": {
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"text/html": [
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"<pre style=\"white-space:pre;overflow-x:auto;line-height:normal;font-family:Menlo,'DejaVu Sans Mono',consolas,'Courier New',monospace\">┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┓\n",
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"┃<span style=\"font-weight: bold\"> Layer (type) </span>┃<span style=\"font-weight: bold\"> Output Shape </span>┃<span style=\"font-weight: bold\"> Param # </span>┃\n",
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"┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━┩\n",
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"│ dense_4 (<span style=\"color: #0087ff; text-decoration-color: #0087ff\">Dense</span>) │ ? │ <span style=\"color: #00af00; text-decoration-color: #00af00\">0</span> (unbuilt) │\n",
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"├─────────────────────────────────┼────────────────────────┼───────────────┤\n",
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"│ dense_5 (<span style=\"color: #0087ff; text-decoration-color: #0087ff\">Dense</span>) │ ? │ <span style=\"color: #00af00; text-decoration-color: #00af00\">0</span> (unbuilt) │\n",
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"├─────────────────────────────────┼────────────────────────┼───────────────┤\n",
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"│ dense_6 (<span style=\"color: #0087ff; text-decoration-color: #0087ff\">Dense</span>) │ ? │ <span style=\"color: #00af00; text-decoration-color: #00af00\">0</span> (unbuilt) │\n",
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"└─────────────────────────────────┴────────────────────────┴───────────────┘\n",
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"</pre>\n"
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],
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"text/plain": [
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"┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┓\n",
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"┃\u001b[1m \u001b[0m\u001b[1mLayer (type) \u001b[0m\u001b[1m \u001b[0m┃\u001b[1m \u001b[0m\u001b[1mOutput Shape \u001b[0m\u001b[1m \u001b[0m┃\u001b[1m \u001b[0m\u001b[1m Param #\u001b[0m\u001b[1m \u001b[0m┃\n",
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"┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━┩\n",
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"│ dense_4 (\u001b[38;5;33mDense\u001b[0m) │ ? │ \u001b[38;5;34m0\u001b[0m (unbuilt) │\n",
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"├─────────────────────────────────┼────────────────────────┼───────────────┤\n",
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"│ dense_5 (\u001b[38;5;33mDense\u001b[0m) │ ? │ \u001b[38;5;34m0\u001b[0m (unbuilt) │\n",
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"├─────────────────────────────────┼────────────────────────┼───────────────┤\n",
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"│ dense_6 (\u001b[38;5;33mDense\u001b[0m) │ ? │ \u001b[38;5;34m0\u001b[0m (unbuilt) │\n",
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"└─────────────────────────────────┴────────────────────────┴───────────────┘\n"
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]
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},
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"metadata": {},
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"output_type": "display_data"
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},
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{
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"data": {
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"text/html": [
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"<pre style=\"white-space:pre;overflow-x:auto;line-height:normal;font-family:Menlo,'DejaVu Sans Mono',consolas,'Courier New',monospace\"><span style=\"font-weight: bold\"> Total params: </span><span style=\"color: #00af00; text-decoration-color: #00af00\">0</span> (0.00 B)\n",
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"</pre>\n"
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],
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"text/plain": [
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"\u001b[1m Total params: \u001b[0m\u001b[38;5;34m0\u001b[0m (0.00 B)\n"
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]
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},
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"metadata": {},
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"output_type": "display_data"
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},
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{
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"data": {
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"text/html": [
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"<pre style=\"white-space:pre;overflow-x:auto;line-height:normal;font-family:Menlo,'DejaVu Sans Mono',consolas,'Courier New',monospace\"><span style=\"font-weight: bold\"> Trainable params: </span><span style=\"color: #00af00; text-decoration-color: #00af00\">0</span> (0.00 B)\n",
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"</pre>\n"
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],
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"text/plain": [
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"\u001b[1m Trainable params: \u001b[0m\u001b[38;5;34m0\u001b[0m (0.00 B)\n"
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]
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},
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"metadata": {},
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"output_type": "display_data"
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},
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{
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"data": {
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"text/html": [
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"<pre style=\"white-space:pre;overflow-x:auto;line-height:normal;font-family:Menlo,'DejaVu Sans Mono',consolas,'Courier New',monospace\"><span style=\"font-weight: bold\"> Non-trainable params: </span><span style=\"color: #00af00; text-decoration-color: #00af00\">0</span> (0.00 B)\n",
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"</pre>\n"
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],
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"text/plain": [
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"\u001b[1m Non-trainable params: \u001b[0m\u001b[38;5;34m0\u001b[0m (0.00 B)\n"
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]
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},
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"metadata": {},
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"output_type": "display_data"
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},
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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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"None\n"
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]
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}
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],
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"source": [
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"# TEST\n",
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"model = Sequential([Dense(units=25,activation='relu'),\n",
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" Dense(units=15,activation='relu'),\n",
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" Dense(units=10,activation='softmax')])\n",
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"model.compile(loss=SparseCategoricalCrossentropy())\n",
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"# 输出模型\n",
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"print(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": 8,
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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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"Epoch 1/5\n"
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]
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},
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{
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"name": "stderr",
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"output_type": "stream",
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"text": [
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"2025-01-21 11:03:07.974903: I tensorflow/core/grappler/optimizers/custom_graph_optimizer_registry.cc:117] Plugin optimizer for device_type GPU is enabled.\n"
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]
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},
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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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"\u001b[1m1875/1875\u001b[0m \u001b[32m━━━━━━━━━━━━━━━━━━━━\u001b[0m\u001b[37m\u001b[0m \u001b[1m16s\u001b[0m 8ms/step - accuracy: 0.8340 - loss: 0.5514\n",
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"Epoch 2/5\n",
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"\u001b[1m1875/1875\u001b[0m \u001b[32m━━━━━━━━━━━━━━━━━━━━\u001b[0m\u001b[37m\u001b[0m \u001b[1m16s\u001b[0m 8ms/step - accuracy: 0.8933 - loss: 0.3836\n",
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"Epoch 3/5\n",
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"\u001b[1m1875/1875\u001b[0m \u001b[32m━━━━━━━━━━━━━━━━━━━━\u001b[0m\u001b[37m\u001b[0m \u001b[1m15s\u001b[0m 8ms/step - accuracy: 0.8902 - loss: 0.4045\n",
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"Epoch 4/5\n",
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"\u001b[1m1875/1875\u001b[0m \u001b[32m━━━━━━━━━━━━━━━━━━━━\u001b[0m\u001b[37m\u001b[0m \u001b[1m15s\u001b[0m 8ms/step - accuracy: 0.8889 - loss: 0.4049\n",
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"Epoch 5/5\n",
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"\u001b[1m1875/1875\u001b[0m \u001b[32m━━━━━━━━━━━━━━━━━━━━\u001b[0m\u001b[37m\u001b[0m \u001b[1m15s\u001b[0m 8ms/step - accuracy: 0.8840 - loss: 0.4177\n",
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"\u001b[1m313/313\u001b[0m \u001b[32m━━━━━━━━━━━━━━━━━━━━\u001b[0m\u001b[37m\u001b[0m \u001b[1m1s\u001b[0m 4ms/step - accuracy: 0.9039 - loss: 0.3451\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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"[0.30404922366142273, 0.9150999784469604]"
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]
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},
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"execution_count": 8,
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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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"# 官方实例\n",
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"\n",
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"import tensorflow as tf\n",
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"mnist = tf.keras.datasets.mnist\n",
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"\n",
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"(x_train, y_train),(x_test, y_test) = mnist.load_data()\n",
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"x_train, x_test = x_train / 255.0, x_test / 255.0\n",
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"\n",
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"model = tf.keras.models.Sequential([\n",
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" tf.keras.layers.Flatten(input_shape=(28, 28)),\n",
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" tf.keras.layers.Dense(128, activation='relu'),\n",
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" tf.keras.layers.Dropout(0.2),\n",
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" tf.keras.layers.Dense(10, activation='softmax')\n",
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"])\n",
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"\n",
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"model.compile(optimizer=tf.keras.optimizers.Adam(learning_rate=0.001),\n",
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" loss=SparseCategoricalCrossentropy(),\n",
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" metrics=['accuracy'])\n",
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"\n",
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"model.fit(x_train, y_train, epochs=5)\n",
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"model.evaluate(x_test, y_test)"
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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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"Epoch 1/5 - Loss: 0.4415533185513543\n",
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"Epoch 2/5 - Loss: 0.24540251612599726\n",
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"Epoch 3/5 - Loss: 0.19663310029716696\n",
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"Epoch 4/5 - Loss: 0.17048093510557338\n",
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"Epoch 5/5 - Loss: 0.16070798563876196\n",
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"Accuracy: 95.38%\n"
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]
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}
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],
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"source": [
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"# 用torch实现\n",
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"\n",
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"import torch\n",
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"import torch.nn as nn\n",
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"import torch.optim as optim\n",
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"from torchvision import datasets, transforms\n",
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"\n",
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"# 数据预处理\n",
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"transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.5,), (0.5,))])\n",
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"\n",
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"# 加载数据集\n",
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"trainset = datasets.MNIST(root='./data', train=True, download=True, transform=transform)\n",
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"trainloader = torch.utils.data.DataLoader(trainset, batch_size=64, shuffle=True)\n",
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"\n",
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"testset = datasets.MNIST(root='./data', train=False, download=True, transform=transform)\n",
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"testloader = torch.utils.data.DataLoader(testset, batch_size=64, shuffle=False)\n",
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"\n",
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"# 定义模型\n",
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"class SimpleNet(nn.Module):\n",
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" def __init__(self):\n",
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" super(SimpleNet, self).__init__()\n",
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" self.flatten = nn.Flatten()\n",
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" self.fc1 = nn.Linear(28 * 28, 128)\n",
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" self.dropout = nn.Dropout(0.2)\n",
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" self.fc2 = nn.Linear(128, 10)\n",
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"\n",
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" def forward(self, x):\n",
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" x = self.flatten(x)\n",
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" x = torch.relu(self.fc1(x))\n",
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" x = self.dropout(x)\n",
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" x = self.fc2(x)\n",
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" return x\n",
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"\n",
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"model = SimpleNet()\n",
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"\n",
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"if torch.backends.mps.is_available():\n",
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" device = torch.device(\"mps\")\n",
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"else:\n",
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" device = torch.device(\"cpu\")\n",
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"\n",
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"model.to(device)\n",
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"\n",
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"# 定义损失函数和优化器\n",
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"criterion = nn.CrossEntropyLoss()\n",
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"optimizer = optim.Adam(model.parameters(), lr=0.001)\n",
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"\n",
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"# 训练模型\n",
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"epochs = 5\n",
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"for epoch in range(epochs):\n",
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" running_loss = 0\n",
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" for images, labels in trainloader:\n",
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" images, labels = images.to(device), labels.to(device) # 将数据移动到设备上\n",
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" optimizer.zero_grad()\n",
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" output = model(images)\n",
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" loss = criterion(output, labels)\n",
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" loss.backward()\n",
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" optimizer.step()\n",
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" running_loss += loss.item()\n",
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" print(f\"Epoch {epoch+1}/{epochs} - Loss: {running_loss/len(trainloader)}\")\n",
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"\n",
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"# 测试模型\n",
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"correct = 0\n",
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"total = 0\n",
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"with torch.no_grad():\n",
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" for images, labels in testloader:\n",
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" images, labels = images.to(device), labels.to(device) # 将数据移动到设备上\n",
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" output = model(images)\n",
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" _, predicted = torch.max(output, 1)\n",
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" total += labels.size(0)\n",
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" correct += (predicted == labels).sum().item()\n",
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"\n",
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"print(f\"Accuracy: {100 * correct / total}%\")"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "ail",
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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": "3.10.16"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 2
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}
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Reference in New Issue
Block a user