From ffa4be4bf4e3758e01d52a9c1f354a05a90b93de Mon Sep 17 00:00:00 2001
From: Gustaf Rydholm <gustaf.rydholm@gmail.com>
Date: Thu, 15 Apr 2021 22:05:24 +0200
Subject: Created mappings

---
 text_recognizer/data/transforms.py | 111 ++++++-------------------------------
 1 file changed, 16 insertions(+), 95 deletions(-)

(limited to 'text_recognizer/data/transforms.py')

diff --git a/text_recognizer/data/transforms.py b/text_recognizer/data/transforms.py
index 297c953..f53df64 100644
--- a/text_recognizer/data/transforms.py
+++ b/text_recognizer/data/transforms.py
@@ -1,115 +1,36 @@
 """Transforms for PyTorch datasets."""
-from abc import abstractmethod
 from pathlib import Path
-from typing import Any, Optional, Union
+from typing import Optional, Union, Sequence
 
-from loguru import logger
-import torch
 from torch import Tensor
 
-from text_recognizer.datasets.iam_preprocessor import Preprocessor
-from text_recognizer.data.emnist import emnist_mapping
+from text_recognizer.datasets.mappings import WordPieceMapping
 
 
-class ToLower:
-    """Converts target to lower case."""
-
-    def __call__(self, target: Tensor) -> Tensor:
-        """Corrects index value in target tensor."""
-        device = target.device
-        return torch.stack([x - 26 if x > 35 else x for x in target]).to(device)
-
-
-class ToCharcters:
-    """Converts integers to characters."""
-
-    def __init__(self, extra_symbols: Optional[List[str]] = None) -> None:
-        self.mapping, _, _ = emnist_mapping(extra_symbols)
-
-    def __call__(self, y: Tensor) -> str:
-        """Converts a Tensor to a str."""
-        return "".join([self.mapping[int(i)] for i in y]).replace(" ", "▁")
-
-
-class WordPieces:
-    """Abstract transform for word pieces."""
+class WordPiece:
+    """Converts EMNIST indices to Word Piece indices."""
 
     def __init__(
         self,
         num_features: int,
+        tokens: str,
+        lexicon: str,
         data_dir: Optional[Union[str, Path]] = None,
-        tokens: Optional[Union[str, Path]] = None,
-        lexicon: Optional[Union[str, Path]] = None,
         use_words: bool = False,
         prepend_wordsep: bool = False,
+        special_tokens: Sequence[str] = ("<s>", "<e>", "<p>"),
+        extra_symbols: Optional[Sequence[str]] = None,
     ) -> None:
-        if data_dir is None:
-            data_dir = (
-                Path(__file__).resolve().parents[3] / "data" / "raw" / "iam" / "iamdb"
-            )
-            logger.debug(f"Using data dir: {data_dir}")
-            if not data_dir.exists():
-                raise RuntimeError(f"Could not locate iamdb directory at {data_dir}")
-        else:
-            data_dir = Path(data_dir)
-        processed_path = (
-            Path(__file__).resolve().parents[3] / "data" / "processed" / "iam_lines"
-        )
-        tokens_path = processed_path / tokens
-        lexicon_path = processed_path / lexicon
-
-        self.preprocessor = Preprocessor(
-            data_dir,
+        self.mapping = WordPieceMapping(
             num_features,
-            tokens_path,
-            lexicon_path,
+            tokens,
+            lexicon,
+            data_dir,
             use_words,
             prepend_wordsep,
+            special_tokens,
+            extra_symbols,
         )
 
-    @abstractmethod
-    def __call__(self, *args, **kwargs) -> Any:
-        """Transforms input."""
-        ...
-
-
-class ToWordPieces(WordPieces):
-    """Transforms str to word pieces."""
-
-    def __init__(
-        self,
-        num_features: int,
-        data_dir: Optional[Union[str, Path]] = None,
-        tokens: Optional[Union[str, Path]] = None,
-        lexicon: Optional[Union[str, Path]] = None,
-        use_words: bool = False,
-        prepend_wordsep: bool = False,
-    ) -> None:
-        super().__init__(
-            num_features, data_dir, tokens, lexicon, use_words, prepend_wordsep
-        )
-
-    def __call__(self, line: str) -> Tensor:
-        """Transforms str to word pieces."""
-        return self.preprocessor.to_index(line)
-
-
-class ToText(WordPieces):
-    """Takes word pieces and converts them to text."""
-
-    def __init__(
-        self,
-        num_features: int,
-        data_dir: Optional[Union[str, Path]] = None,
-        tokens: Optional[Union[str, Path]] = None,
-        lexicon: Optional[Union[str, Path]] = None,
-        use_words: bool = False,
-        prepend_wordsep: bool = False,
-    ) -> None:
-        super().__init__(
-            num_features, data_dir, tokens, lexicon, use_words, prepend_wordsep
-        )
-
-    def __call__(self, x: Tensor) -> str:
-        """Converts tensor to text."""
-        return self.preprocessor.to_text(x.tolist())
+    def __call__(self, x: Tensor) -> Tensor:
+        return self.mapping.emnist_to_wordpiece_indices(x)
-- 
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