autograd part two

video/autograd_part_two.ipynb

@@ -0,0 +1,744 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import sys\n",
+    "import os\n",
+    "sys.path.append(os.path.abspath(os.path.join('../ch07_autograd')))\n",
+    "from utils import Scalar, draw_graph\n",
+    "from linear_model import Linear, mse"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "<torch._C.Generator at 0x7fd5a87a86d0>"
+      ]
+     },
+     "execution_count": 2,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "import torch\n",
+    "\n",
+    "torch.manual_seed(1024)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "x = torch.linspace(100, 300, 200)\n",
+    "x = (x - torch.mean(x)) / torch.std(x)\n",
+    "epsilon = torch.randn(x.shape)\n",
+    "y = 10 * x + 5 + epsilon"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "y = 3.12 * x + -1.99\n",
+      "y = 3.48 * x + -2.28\n",
+      "y = 3.22 * x + -1.97\n",
+      "y = 2.85 * x + -1.22\n",
+      "y = 2.68 * x + -0.23\n",
+      "y = 2.92 * x + 1.08\n",
+      "y = 3.74 * x + 2.61\n",
+      "y = 5.07 * x + 4.15\n",
+      "y = 6.73 * x + 5.52\n",
+      "y = 8.22 * x + 6.48\n",
+      "y = 9.36 * x + 5.75\n",
+      "y = 9.75 * x + 5.42\n",
+      "y = 9.88 * x + 5.28\n",
+      "y = 9.89 * x + 5.26\n",
+      "y = 9.89 * x + 5.20\n",
+      "y = 9.88 * x + 5.18\n",
+      "y = 9.88 * x + 5.17\n",
+      "y = 9.84 * x + 5.14\n",
+      "y = 9.86 * x + 5.15\n",
+      "y = 9.94 * x + 5.21\n"
+     ]
+    }
+   ],
+   "source": [
+    "model = Linear()\n",
+    "\n",
+    "batch_size = 20\n",
+    "learning_rate = 0.1\n",
+    "\n",
+    "for t in range(20):\n",
+    "    ix = (t * batch_size) % len(x)\n",
+    "    xx = x[ix: ix + batch_size]\n",
+    "    yy = y[ix: ix + batch_size]\n",
+    "    loss = mse([model.error(_x, _y) for _x, _y in zip(xx, yy)])\n",
+    "    loss.backward()\n",
+    "    model.a -= learning_rate * model.a.grad\n",
+    "    model.b -= learning_rate * model.b.grad\n",
+    "    model.a.grad = 0.0\n",
+    "    model.b.grad = 0.0\n",
+    "    print(model.string())"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [
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+     "execution_count": 5,
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+     "output_type": "execute_result"
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+   ],
+   "source": [
+    "# 计算图膨胀\n",
+    "model = Linear()\n",
+    "# 定义两组数据\n",
+    "x1 = Scalar(1.5, label='x1', requires_grad=False)\n",
+    "y1 = Scalar(1.0, label='y1', requires_grad=False)\n",
+    "x2 = Scalar(2.0, label='x2', requires_grad=False)\n",
+    "y2 = Scalar(4.0, label='y2', requires_grad=False)\n",
+    "loss = mse([model.error(x1, y1), model.error(x2, y2)])\n",
+    "loss.backward()\n",
+    "draw_graph(loss, 'backward')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [
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+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "# 第一次传播\n",
+    "model = Linear()\n",
+    "loss = 0.5 * mse([model.error(x1, y1)])\n",
+    "loss.backward()\n",
+    "draw_graph(loss, 'backward')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {},
+   "outputs": [
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+     },
+     "execution_count": 8,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "# 第二次传播（梯度积累）\n",
+    "loss = 0.5 * mse([model.error(x2, y2)])\n",
+    "loss.backward()\n",
+    "draw_graph(loss, 'backward')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "y = 3.12 * x + -1.99\n",
+      "y = 3.48 * x + -2.28\n",
+      "y = 3.22 * x + -1.97\n",
+      "y = 2.85 * x + -1.22\n",
+      "y = 2.68 * x + -0.23\n",
+      "y = 2.92 * x + 1.08\n",
+      "y = 3.74 * x + 2.61\n",
+      "y = 5.07 * x + 4.15\n",
+      "y = 6.73 * x + 5.52\n",
+      "y = 8.22 * x + 6.48\n",
+      "y = 9.36 * x + 5.75\n",
+      "y = 9.75 * x + 5.42\n",
+      "y = 9.88 * x + 5.28\n",
+      "y = 9.89 * x + 5.26\n",
+      "y = 9.89 * x + 5.20\n",
+      "y = 9.88 * x + 5.18\n",
+      "y = 9.88 * x + 5.17\n",
+      "y = 9.84 * x + 5.14\n",
+      "y = 9.86 * x + 5.15\n",
+      "y = 9.94 * x + 5.21\n"
+     ]
+    }
+   ],
+   "source": [
+    "model = Linear()\n",
+    "\n",
+    "batch_size = 20\n",
+    "learning_rate = 0.1\n",
+    "# 梯度积累次数\n",
+    "gradient_accu_iter = 4\n",
+    "# 小批量数据量\n",
+    "micro_size = int(batch_size / gradient_accu_iter)\n",
+    "\n",
+    "\n",
+    "for t in range(20 * gradient_accu_iter):\n",
+    "    ix = (t * micro_size) % len(x)\n",
+    "    xx = x[ix: ix + micro_size]\n",
+    "    yy = y[ix: ix + micro_size]\n",
+    "    loss = mse([model.error(_x, _y) for _x, _y in zip(xx, yy)])\n",
+    "    # 调整权重\n",
+    "    loss *= 1 / gradient_accu_iter\n",
+    "    loss.backward()\n",
+    "    if (t + 1) % gradient_accu_iter == 0:\n",
+    "        model.a -= learning_rate * model.a.grad\n",
+    "        model.b -= learning_rate * model.b.grad\n",
+    "        model.a.grad = 0.0\n",
+    "        model.b.grad = 0.0\n",
+    "        print(model.string())\n",
+    "    #model.a -= learning_rate * model.a.grad\n",
+    "    #model.b -= learning_rate * model.b.grad\n",
+    "    #model.a.grad = 0.0\n",
+    "    #model.b.grad = 0.0\n",
+    "    #print(model.string())"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
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+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
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