lab-10_1_mnist_cnn.ipynb

{
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  {
   "cell_type": "code",
   "execution_count": null,
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   "source": [
    "# Lab 11 MNIST and Convolutional Neural Network\n",
    "import torch\n",
    "import torchvision.datasets as dsets\n",
    "import torchvision.transforms as transforms\n",
    "import torch.nn.init"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "device = 'cuda' if torch.cuda.is_available() else 'cpu'\n",
    "\n",
    "# for reproducibility\n",
    "torch.manual_seed(777)\n",
    "if device == 'cuda':\n",
    "    torch.cuda.manual_seed_all(777)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# parameters\n",
    "learning_rate = 0.001\n",
    "training_epochs = 15\n",
    "batch_size = 100"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# MNIST dataset\n",
    "mnist_train = dsets.MNIST(root='MNIST_data/',\n",
    "                          train=True,\n",
    "                          transform=transforms.ToTensor(),\n",
    "                          download=True)\n",
    "\n",
    "mnist_test = dsets.MNIST(root='MNIST_data/',\n",
    "                         train=False,\n",
    "                         transform=transforms.ToTensor(),\n",
    "                         download=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# dataset loader\n",
    "data_loader = torch.utils.data.DataLoader(dataset=mnist_train,\n",
    "                                          batch_size=batch_size,\n",
    "                                          shuffle=True,\n",
    "                                          drop_last=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# CNN Model (2 conv layers)\n",
    "class CNN(torch.nn.Module):\n",
    "\n",
    "    def __init__(self):\n",
    "        super(CNN, self).__init__()\n",
    "        # L1 ImgIn shape=(?, 28, 28, 1)\n",
    "        #    Conv     -> (?, 28, 28, 32)\n",
    "        #    Pool     -> (?, 14, 14, 32)\n",
    "        self.layer1 = torch.nn.Sequential(\n",
    "            torch.nn.Conv2d(1, 32, kernel_size=3, stride=1, padding=1),\n",
    "            torch.nn.ReLU(),\n",
    "            torch.nn.MaxPool2d(kernel_size=2, stride=2))\n",
    "        # L2 ImgIn shape=(?, 14, 14, 32)\n",
    "        #    Conv      ->(?, 14, 14, 64)\n",
    "        #    Pool      ->(?, 7, 7, 64)\n",
    "        self.layer2 = torch.nn.Sequential(\n",
    "            torch.nn.Conv2d(32, 64, kernel_size=3, stride=1, padding=1),\n",
    "            torch.nn.ReLU(),\n",
    "            torch.nn.MaxPool2d(kernel_size=2, stride=2))\n",
    "        # Final FC 7x7x64 inputs -> 10 outputs\n",
    "        self.fc = torch.nn.Linear(7 * 7 * 64, 10, bias=True)\n",
    "        torch.nn.init.xavier_uniform_(self.fc.weight)\n",
    "\n",
    "    def forward(self, x):\n",
    "        out = self.layer1(x)\n",
    "        out = self.layer2(out)\n",
    "        out = out.view(out.size(0), -1)   # Flatten them for FC\n",
    "        out = self.fc(out)\n",
    "        return out"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# instantiate CNN model\n",
    "model = CNN().to(device)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# define cost/loss & optimizer\n",
    "criterion = torch.nn.CrossEntropyLoss().to(device)    # Softmax is internally computed.\n",
    "optimizer = torch.optim.Adam(model.parameters(), lr=learning_rate)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# train my model\n",
    "total_batch = len(data_loader)\n",
    "print('Learning started. It takes sometime.')\n",
    "for epoch in range(training_epochs):\n",
    "    avg_cost = 0\n",
    "\n",
    "    for X, Y in data_loader:\n",
    "        # image is already size of (28x28), no reshape\n",
    "        # label is not one-hot encoded\n",
    "        X = X.to(device)\n",
    "        Y = Y.to(device)\n",
    "\n",
    "        optimizer.zero_grad()\n",
    "        hypothesis = model(X)\n",
    "        cost = criterion(hypothesis, Y)\n",
    "        cost.backward()\n",
    "        optimizer.step()\n",
    "\n",
    "        avg_cost += cost / total_batch\n",
    "\n",
    "    print('[Epoch: {:>4}] cost = {:>.9}'.format(epoch + 1, avg_cost))\n",
    "\n",
    "print('Learning Finished!')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Test model and check accuracy\n",
    "with torch.no_grad():\n",
    "    X_test = mnist_test.test_data.view(len(mnist_test), 1, 28, 28).float().to(device)\n",
    "    Y_test = mnist_test.test_labels.to(device)\n",
    "\n",
    "    prediction = model(X_test)\n",
    "    correct_prediction = torch.argmax(prediction, 1) == Y_test\n",
    "    accuracy = correct_prediction.float().mean()\n",
    "    print('Accuracy:', accuracy.item())"
   ]
  }
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