[DOC] Small fixes in graph alignment tutorial

nbs/tutorials/graph_alignment.ipynb

@@ -121,6 +121,7 @@
     "\n",
     "# Create the Laplacian matrix of the first graph\n",
     "x = create_test_sbm_laplacian(block_sizes, probs)\n",
+    "n_nodes = len(x)  # In case the number of nodes has changed due to removal of isolates\n",
     "\n",
     "# Define the second graph by randomly permuting the nodes in the first\n",
     "P = torch.zeros_like(x)\n",
@@ -146,7 +147,9 @@
     "from diffpass.train import GraphAlignment, IntraGroupSimilarityLoss\n",
     "\n",
     "group_sizes = [n_nodes]\n",
-    "comparison_loss = IntraGroupSimilarityLoss(group_sizes=group_sizes, exclude_diagonal=False)  # Default behaviour except for inclusion of the main diagonal\n",
+    "comparison_loss = IntraGroupSimilarityLoss(\n",
+    "    group_sizes=group_sizes, exclude_diagonal=False\n",
+    ")  # Default behaviour except for inclusion of the main diagonal\n",
     "\n",
     "# Initialize the GraphAlignment model\n",
     "graph_alignment = GraphAlignment(\n",
@@ -203,8 +206,6 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "from diffpass.data_utils import compute_num_correct_pairings\n",
-    "\n",
     "def plot_hard_losses(\n",
     "    results,\n",
     "    target_hard_loss: Optional[float] = None\n",