chore: import upstream snapshot with attribution

decoding/GAD/fairseq/modules/gelu.py

@@ -0,0 +1,25 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+"""
+See "Gaussian Error Linear Units (GELUs)" by Dan Hendrycks and Kevin Gimpel with
+the corresponding GitHub repo: https://github.com/hendrycks/GELUs
+"""
+
+import math
+
+import torch
+import torch.nn as nn
+
+
+def gelu_accurate(x):
+    if not hasattr(gelu_accurate, "_a"):
+        gelu_accurate._a = math.sqrt(2 / math.pi)
+    return (
+        0.5 * x * (1 + torch.tanh(gelu_accurate._a * (x + 0.044715 * torch.pow(x, 3))))
+    )
+
+
+def gelu(x: torch.Tensor) -> torch.Tensor:
+    return torch.nn.functional.gelu(x.float()).type_as(x)