Merge pull request #695 from eriklindernoren/feature/mish_activation_…

…function

Add support for the mish activation function

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "PyTorchYolo"
-version = "1.3.2"
+version = "1.4.0"
 readme = "README.md"
 repository = "https://github.com/eriklindernoren/PyTorch-YOLOv3"
 description = "Minimal PyTorch implementation of YOLO"

pytorchyolo/models.py

@@ -59,6 +59,8 @@ def create_modules(module_defs):
                                    nn.BatchNorm2d(filters, momentum=0.9, eps=1e-5))
             if module_def["activation"] == "leaky":
                 modules.add_module(f"leaky_{module_i}", nn.LeakyReLU(0.1))
+            if module_def["activation"] == "mish":
+                modules.add_module(f"mish_{module_i}", Mish())
 
         elif module_def["type"] == "maxpool":
             kernel_size = int(module_def["size"])
@@ -111,6 +113,14 @@ def forward(self, x):
         x = F.interpolate(x, scale_factor=self.scale_factor, mode=self.mode)
         return x
 
+class Mish(nn.Module):
+    """ The MISH activation function (https://github.com/digantamisra98/Mish) """
+
+    def __init__(self):
+        super(Mish, self).__init__()
+
+    def forward(self, x):
+        return x * torch.tanh(F.softplus(x))
 
 class YOLOLayer(nn.Module):
     """Detection layer"""