Fix shape of node_weight in METIS (#342)

* update

* update

Author: rusty1s

.github/workflows/testing.yml

@@ -48,6 +48,7 @@ jobs:
 
       - name: Install main package
         run: |
+          pip install scipy
           python setup.py develop
         env:
           WITH_METIS: 1

torch_sparse/metis.py

@@ -52,7 +52,7 @@ def partition(
         value = None
 
     if balance_edge:
-        node_weight = col.new_zeros(col.size(0))
+        node_weight = col.new_zeros(rowptr.numel() - 1)
         node_weight.scatter_add_(0, col, torch.ones_like(col))
 
     if node_weight is not None: