Fix deprecation warning in sigmoid

src/nets/util.py

@@ -2,13 +2,11 @@ import torch
 from torch.nn import functional
 
 def parse_functional(functional_config):
-    if functional_config is None:
+    if isinstance(functional_config, str):
-        return None
-    elif isinstance(functional_config, str):
         if functional_config == 'relu':
             return functional.relu
         elif functional_config == 'sigmoid':
-            return functional.sigmoid
+            return torch.sigmoid
         elif functional_config == 'softmax':
             return functional.softmax
-    
+    return None

tests/nets/test_deepsets.py

@@ -24,7 +24,11 @@ def test_constructor():
     phi_config["output_dim"] = 2
     phi_config["final_activation"] = "sigmoid"
     phi = ds.Phi.from_config(phi_config)
-    assert phi.final_activation == torch.nn.functional.sigmoid
+    assert phi.final_activation == torch.sigmoid
+
+    phi_config["final_activation"] = "relu"
+    phi = ds.Phi.from_config(phi_config)
+    assert phi.final_activation == torch.nn.functional.relu
 
 def test_phi():
     input_dim = 5