Fixing invalid index of a 0-dim tensor.

Fixing invalid index of a 0-dim tensor. This will be an error in PyTorch 0.5. Use tensor.item() to convert a 0-dim tensor to a Python number

Author: Hierom

chapter3_NN/deep-nn.ipynb

@@ -507,10 +507,10 @@
     "        loss.backward()\n",
     "        optimizer.step()\n",
     "        # 记录误差\n",
-    "        train_loss += loss.data[0]\n",
+    "        train_loss += loss.item()\n",
     "        # 计算分类的准确率\n",
     "        _, pred = out.max(1)\n",
-    "        num_correct = (pred == label).sum().data[0]\n",
+    "        num_correct = (pred == label).sum().item()\n",
     "        acc = num_correct / im.shape[0]\n",
     "        train_acc += acc\n",
     "        \n",
@@ -526,10 +526,10 @@
     "        out = net(im)\n",
     "        loss = criterion(out, label)\n",
     "        # 记录误差\n",
-    "        eval_loss += loss.data[0]\n",
+    "        eval_loss += loss.item()\n",
     "        # 记录准确率\n",
     "        _, pred = out.max(1)\n",
-    "        num_correct = (pred == label).sum().data[0]\n",
+    "        num_correct = (pred == label).sum().item()\n",
     "        acc = num_correct / im.shape[0]\n",
     "        eval_acc += acc\n",
     "        \n",