Update train_cnn.ipynb

Call model.merge_bn() if available

DeepCrazyhouse/src/training/train_cnn.ipynb

@@ -1145,6 +1145,29 @@
     "print('best val_loss: %.5f with v_policy_acc: %.5f at k_steps_best %d' % (val_loss_best, val_p_acc_best, k_steps_best))"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "source": [
+    "## Merge Batchnorm layers (if possible)\n",
+    "\n",
+    "This is required for the AlphaVile networks that use the Next Transformer Block (NTB)."
+   ],
+   "metadata": {
+    "collapsed": false
+   }
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "outputs": [],
+   "source": [
+    "if hasattr(model, \"merge_bn\"):\n",
+    "    model.merge_bn()"
+   ],
+   "metadata": {
+    "collapsed": false
+   }
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -1715,4 +1738,4 @@
  },
  "nbformat": 4,
  "nbformat_minor": 4
-}
+}