1 files changed, 57 insertions, 0 deletions
diff --git a/text_recognizer/network/transformer/decoder.py b/text_recognizer/network/transformer/decoder.py
new file mode 100644
index 0000000..06925ba
--- /dev/null
+++ b/text_recognizer/network/transformer/decoder.py
@@ -0,0 +1,57 @@
+"""Transformer decoder module."""
+from typing import Optional
+from torch import Tensor, nn
+
+from text_recognizer.network.transformer.attention import Attention
+from text_recognizer.network.transformer.ff import FeedForward
+
+
+class Decoder(nn.Module):
+    def __init__(
+        self,
+        dim: int,
+        inner_dim: int,
+        heads: int,
+        dim_head: int,
+        depth: int,
+        dropout_rate: float = 0.0,
+    ) -> None:
+        super().__init__()
+        self.norm = nn.LayerNorm(dim)
+        self.layers = nn.ModuleList(
+            [
+                nn.ModuleList(
+                    [
+                        Attention(
+                            dim,
+                            heads,
+                            True,
+                            dim_head,
+                            dropout_rate,
+                        ),
+                        FeedForward(dim, inner_dim, dropout_rate),
+                        Attention(
+                            dim,
+                            heads,
+                            False,
+                            dim_head,
+                            dropout_rate,
+                        ),
+                    ]
+                )
+                for _ in range(depth)
+            ]
+        )
+
+    def forward(
+        self,
+        x: Tensor,
+        context: Tensor,
+        mask: Optional[Tensor] = None,
+    ) -> Tensor:
+        """Applies decoder block on input signals."""
+        for self_attn, ff, cross_attn in self.layers:
+            x = x + self_attn(x, mask=mask)
+            x = x + ff(x)
+            x = x + cross_attn(x, context=context)
+        return self.norm(x)