Add preliminary gMLP and ResMLP impl to Mlp-Mixer

tests/test_models.py

@@ -15,7 +15,7 @@
     torch._C._jit_set_profiling_mode(False)
 
 # transformer models don't support many of the spatial / feature based model functionalities
-NON_STD_FILTERS = ['vit_*', 'tnt_*', 'pit_*', 'swin_*', 'coat_*', 'cait_*', 'mixer_*']
+NON_STD_FILTERS = ['vit_*', 'tnt_*', 'pit_*', 'swin_*', 'coat_*', 'cait_*', '*mixer_*', 'gmlp_*', 'resmlp_*']
 NUM_NON_STD = len(NON_STD_FILTERS)
 
 # exclude models that cause specific test failures

timm/models/layers/__init__.py

@@ -20,7 +20,7 @@
 from .inplace_abn import InplaceAbn
 from .linear import Linear
 from .mixed_conv2d import MixedConv2d
-from .mlp import Mlp, GluMlp
+from .mlp import Mlp, GluMlp, GatedMlp
 from .norm import GroupNorm
 from .norm_act import BatchNormAct2d, GroupNormAct
 from .padding import get_padding, get_same_padding, pad_same

timm/models/layers/mlp.py

@@ -34,9 +34,10 @@ def __init__(self, in_features, hidden_features=None, out_features=None, act_lay
         super().__init__()
         out_features = out_features or in_features
         hidden_features = hidden_features or in_features
-        self.fc1 = nn.Linear(in_features, hidden_features * 2)
+        assert hidden_features % 2 == 0
+        self.fc1 = nn.Linear(in_features, hidden_features)
         self.act = act_layer()
-        self.fc2 = nn.Linear(hidden_features, out_features)
+        self.fc2 = nn.Linear(hidden_features // 2, out_features)
         self.drop = nn.Dropout(drop)
 
     def forward(self, x):
@@ -47,3 +48,32 @@ def forward(self, x):
         x = self.fc2(x)
         x = self.drop(x)
         return x
+
+
+class GatedMlp(nn.Module):
+    """ MLP as used in gMLP
+    """
+    def __init__(self, in_features, hidden_features=None, out_features=None, act_layer=nn.GELU,
+                 gate_layer=None, drop=0.):
+        super().__init__()
+        out_features = out_features or in_features
+        hidden_features = hidden_features or in_features
+        self.fc1 = nn.Linear(in_features, hidden_features)
+        self.act = act_layer()
+        if gate_layer is not None:
+            assert hidden_features % 2 == 0
+            self.gate = gate_layer(hidden_features)
+            hidden_features = hidden_features // 2  # FIXME base reduction on gate property?
+        else:
+            self.gate = nn.Identity()
+        self.fc2 = nn.Linear(hidden_features, out_features)
+        self.drop = nn.Dropout(drop)
+
+    def forward(self, x):
+        x = self.fc1(x)
+        x = self.act(x)
+        x = self.drop(x)
+        x = self.gate(x)
+        x = self.fc2(x)
+        x = self.drop(x)
+        return x