1 files changed, 46 insertions, 0 deletions
diff --git a/text_recognizer/networks/transformer/decoder_block.py b/text_recognizer/networks/transformer/decoder_block.py
new file mode 100644
index 0000000..e6e7fb8
--- /dev/null
+++ b/text_recognizer/networks/transformer/decoder_block.py
@@ -0,0 +1,46 @@
+"""Transformer decoder module."""
+from copy import deepcopy
+from typing import Optional, Type
+
+from torch import Tensor, nn
+
+from text_recognizer.networks.transformer.attention import Attention
+from text_recognizer.networks.transformer.ff import FeedForward
+
+
+class DecoderBlock(nn.Module):
+    """Decoder block."""
+
+    def __init__(
+        self,
+        self_attn: Attention,
+        norm: Type[nn.Module],
+        ff: FeedForward,
+        cross_attn: Optional[Attention] = None,
+    ) -> None:
+        super().__init__()
+        self.ln_attn = norm
+        self.attn = self_attn
+        self.ln_cross_attn = deepcopy(norm)
+        self.cross_attn = cross_attn
+        self.ln_ff = deepcopy(norm)
+        self.ff = ff
+        self.has_pos_emb = self.attn.rotary_embedding is not None
+
+    def forward(
+        self,
+        x: Tensor,
+        context: Optional[Tensor] = None,
+        input_mask: Optional[Tensor] = None,
+        context_mask: Optional[Tensor] = None,
+    ) -> Tensor:
+        """Applies decoder block on input signals."""
+        x = x + self.attn(self.ln_attn(x), input_mask=input_mask)
+        x += self.cross_attn(
+            x=self.ln_cross_attn(x),
+            context=context,
+            input_mask=input_mask,
+            context_mask=context_mask,
+        )
+        x += self.ff(self.ln_ff(x))
+        return x