Update appnpconv.py (#2324)

python/dgl/nn/pytorch/conv/appnpconv.py

@@ -88,13 +88,16 @@ class APPNPConv(nn.Module):
             should be the same as input shape.
         """
         with graph.local_scope():
-            norm = th.pow(graph.in_degrees().float().clamp(min=1), -0.5)
-            shp = norm.shape + (1,) * (feat.dim() - 1)
-            norm = th.reshape(norm, shp).to(feat.device)
+            src_norm = th.pow(graph.out_degrees().float().clamp(min=1), -0.5)
+            shp = src_norm.shape + (1,) * (feat.dim() - 1)
+            src_norm = th.reshape(src_norm, shp).to(feat.device)
+            dst_norm = th.pow(graph.in_degrees().float().clamp(min=1), -0.5)
+            shp = dst_norm.shape + (1,) * (feat.dim() - 1)
+            dst_norm = th.reshape(dst_norm, shp).to(feat.device)
             feat_0 = feat
             for _ in range(self._k):
                 # normalization by src node
-                feat = feat * norm
+                feat = feat * src_norm
                 graph.ndata['h'] = feat
                 graph.edata['w'] = self.edge_drop(
                     th.ones(graph.number_of_edges(), 1).to(feat.device))
@@ -102,6 +105,6 @@ class APPNPConv(nn.Module):
                                  fn.sum('m', 'h'))
                 feat = graph.ndata.pop('h')
                 # normalization by dst node
-                feat = feat * norm
+                feat = feat * dst_norm
                 feat = (1 - self._alpha) * feat + self._alpha * feat_0
             return feat