swish glu feedforward from shazeer et al

dreamer4/dreamer4.py

@@ -5,7 +5,7 @@ from functools import partial
 
 import torch
 import torch.nn.functional as F
-from torch.nn import Module, ModuleList, Linear, RMSNorm, Identity
+from torch.nn import Module, ModuleList, Sequential, Linear, RMSNorm, Identity
 from torch import cat, stack, tensor, Tensor, is_tensor
 
 # ein related
@@ -25,7 +25,7 @@ def exists(v):
 def default(v, d):
     return v if exists(v) else d
 
-# classes
+# attention
 
 class Attention(Module):
     def __init__(
@@ -80,3 +80,28 @@ class Attention(Module):
             return out
 
         return out, stack((k, v))
+
+# feedforward
+
+class SwiGLUFeedforward(Module):
+    def __init__(
+        self,
+        dim,
+        expansion_factor = 4,
+        pre_rmsnorm = True
+    ):
+        super().__init__()
+        self.norm = RMSNorm(dim) if pre_rmsnorm else Identity()
+
+        dim_inner = int(dim * expansion_factor * 2 / 3)
+
+        self.proj_in = Linear(dim, dim_inner * 2)
+        self.proj_out = Linear(dim_inner, dim)
+
+    def forward(self, x):
+        x = self.norm(x)
+
+        x, gates = self.proj_in(x).chunk(2, dim = -1)
+        x = x * F.gelu(gates)
+
+        return self.proj_out(x)

tests/test_dreamer.py

@@ -1,3 +1,17 @@
+import pytest
+import torch
 
-def test_dreamer():
-    assert True
+def test_attn():
+    from dreamer4.dreamer4 import Attention
+
+    x = torch.randn(1, 1024, 512)
+    attn = Attention(512)
+
+    assert attn(x).shape == x.shape
+
+def test_ff():
+    from dreamer4.dreamer4 import SwiGLUFeedforward
+    x = torch.randn(1, 1024, 512)
+    ff = SwiGLUFeedforward(512)
+
+    assert ff(x).shape == x.shape