Fix node_attributes shape in read_tu_data (#5441)

* Fix node_attributes shape

* Update tu.py

* Update CHANGELOG.md

Co-authored-by: Matthias Fey <matthias.fey@tu-dortmund.de>

CHANGELOG.md

@@ -20,6 +20,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added `BaseStorage.get()` functionality ([#5240](https://github.com/pyg-team/pytorch_geometric/pull/5240))
 - Added a test to confirm that `to_hetero` works with `SparseTensor` ([#5222](https://github.com/pyg-team/pytorch_geometric/pull/5222))
 ### Changed
+- Fixed a bug in `TUDataset` in which node features were wrongly constructed whenever `node_attributes` only hold a single feature (*e.g.*, in `PROTEINS`) ([#5441](https://github.com/pyg-team/pytorch_geometric/pull/5411))
 - Breaking change: removed `num_neighbors` as an attribute of loader ([#5404](https://github.com/pyg-team/pytorch_geometric/pull/5404))
 - `ASAPooling` is now jittable ([#5395](https://github.com/pyg-team/pytorch_geometric/pull/5395))
 - Updated unsupervised `GraphSAGE` example to leverage `LinkNeighborLoader` ([#5317](https://github.com/pyg-team/pytorch_geometric/pull/5317))

torch_geometric/io/tu.py

@@ -27,6 +27,8 @@ def read_tu_data(folder, prefix):
     node_attributes = torch.empty((batch.size(0), 0))
     if 'node_attributes' in names:
         node_attributes = read_file(folder, prefix, 'node_attributes')
+        if node_attributes.dim() == 1:
+            node_attributes = node_attributes.unsqueeze(-1)
 
     node_labels = torch.empty((batch.size(0), 0))
     if 'node_labels' in names:
@@ -41,6 +43,8 @@ def read_tu_data(folder, prefix):
     edge_attributes = torch.empty((edge_index.size(1), 0))
     if 'edge_attributes' in names:
         edge_attributes = read_file(folder, prefix, 'edge_attributes')
+        if edge_attributes.dim() == 1:
+            edge_attributes = edge_attributes.unsqueeze(-1)
 
     edge_labels = torch.empty((edge_index.size(1), 0))
     if 'edge_labels' in names: