From c9c60678673e19ad3367339eb8e7a093e5a98474 Mon Sep 17 00:00:00 2001
From: Gustaf Rydholm <gustaf.rydholm@gmail.com>
Date: Sun, 9 May 2021 22:46:09 +0200
Subject: Reformatting of positional encodings and ViT working

---
 .../networks/transformer/positional_encoding.py    | 85 ----------------------
 1 file changed, 85 deletions(-)
 delete mode 100644 text_recognizer/networks/transformer/positional_encoding.py

(limited to 'text_recognizer/networks/transformer/positional_encoding.py')

diff --git a/text_recognizer/networks/transformer/positional_encoding.py b/text_recognizer/networks/transformer/positional_encoding.py
deleted file mode 100644
index c50afc3..0000000
--- a/text_recognizer/networks/transformer/positional_encoding.py
+++ /dev/null
@@ -1,85 +0,0 @@
-"""A positional encoding for the image features, as the transformer has no notation of the order of the sequence."""
-from einops import repeat
-import numpy as np
-import torch
-from torch import nn
-from torch import Tensor
-
-
-class PositionalEncoding(nn.Module):
-    """Encodes a sense of distance or time for transformer networks."""
-
-    def __init__(
-        self, hidden_dim: int, dropout_rate: float, max_len: int = 1000
-    ) -> None:
-        super().__init__()
-        self.dropout = nn.Dropout(p=dropout_rate)
-        pe = self.make_pe(hidden_dim, max_len)
-        self.register_buffer("pe", pe)
-
-    @staticmethod
-    def make_pe(hidden_dim: int, max_len: int) -> Tensor:
-        """Returns positional encoding."""
-        pe = torch.zeros(max_len, hidden_dim)
-        position = torch.arange(0, max_len, dtype=torch.float).unsqueeze(1)
-        div_term = torch.exp(
-            torch.arange(0, hidden_dim, 2).float() * (-np.log(10000.0) / hidden_dim)
-        )
-
-        pe[:, 0::2] = torch.sin(position * div_term)
-        pe[:, 1::2] = torch.cos(position * div_term)
-        pe = pe.unsqueeze(1)
-        return pe
-
-    def forward(self, x: Tensor) -> Tensor:
-        """Encodes the tensor with a postional embedding."""
-        # [T, B, D]
-        if x.shape[2] != self.pe.shape[2]:
-            raise ValueError(f"x shape does not match pe in the 3rd dim.")
-        x = x + self.pe[: x.shape[0]]
-        return self.dropout(x)
-
-
-class PositionalEncoding2D(nn.Module):
-    """Positional encodings for feature maps."""
-
-    def __init__(self, hidden_dim: int, max_h: int = 2048, max_w: int = 2048) -> None:
-        super().__init__()
-        if hidden_dim % 2 != 0:
-            raise ValueError(f"Embedding depth {hidden_dim} is not even!")
-        self.hidden_dim = hidden_dim
-        pe = self.make_pe(hidden_dim, max_h, max_w)
-        self.register_buffer("pe", pe)
-
-    @staticmethod
-    def make_pe(hidden_dim: int, max_h: int, max_w: int) -> Tensor:
-        """Returns 2d postional encoding."""
-        pe_h = PositionalEncoding.make_pe(
-            hidden_dim // 2, max_len=max_h
-        )  # [H, 1, D // 2]
-        pe_h = repeat(pe_h, "h w d -> d h (w tile)", tile=max_w)
-
-        pe_w = PositionalEncoding.make_pe(
-            hidden_dim // 2, max_len=max_w
-        )  # [W, 1, D // 2]
-        pe_w = repeat(pe_w, "w h d -> d (h tile) w", tile=max_h)
-
-        pe = torch.cat([pe_h, pe_w], dim=0)  # [D, H, W]
-        return pe
-
-    def forward(self, x: Tensor) -> Tensor:
-        """Adds 2D postional encoding to input tensor."""
-        # Assumes x hase shape [B, D, H, W]
-        if x.shape[1] != self.pe.shape[0]:
-            raise ValueError("Hidden dimensions does not match.")
-        x += self.pe[:, : x.shape[2], : x.shape[3]]
-        return x
-
-
-def target_padding_mask(trg: Tensor, pad_index: int) -> Tensor:
-    """Returns causal target mask."""
-    trg_pad_mask = (trg != pad_index)[:, None, None]
-    trg_len = trg.shape[1]
-    trg_sub_mask = torch.tril(torch.ones((trg_len, trg_len), device=trg.device)).bool()
-    trg_mask = trg_pad_mask & trg_sub_mask
-    return trg_mask
-- 
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