From f61ebe086f912d3becd6c636378ae18d4b876602 Mon Sep 17 00:00:00 2001
From: Gustaf Rydholm <gustaf.rydholm@gmail.com>
Date: Tue, 8 Jun 2021 21:50:33 +0200
Subject: Lint and metadata files

---
 text_recognizer/data/emnist.py | 40 ++++++++++++++++++++++++++++------------
 1 file changed, 28 insertions(+), 12 deletions(-)

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

diff --git a/text_recognizer/data/emnist.py b/text_recognizer/data/emnist.py
index 12adaab..bf3faec 100644
--- a/text_recognizer/data/emnist.py
+++ b/text_recognizer/data/emnist.py
@@ -1,22 +1,22 @@
 """EMNIST dataset: downloads it from FSDL aws url if not present."""
-from pathlib import Path
-from typing import Dict, List, Optional, Sequence, Tuple
 import json
 import os
+from pathlib import Path
 import shutil
+from typing import Dict, List, Optional, Sequence, Tuple
 import zipfile
 
 import h5py
-import numpy as np
 from loguru import logger
+import numpy as np
 import toml
 from torchvision import transforms
 
-from text_recognizer.data.base_dataset import BaseDataset, split_dataset
 from text_recognizer.data.base_data_module import (
     BaseDataModule,
     load_and_print_info,
 )
+from text_recognizer.data.base_dataset import BaseDataset, split_dataset
 from text_recognizer.data.download_utils import download_dataset
 
 
@@ -33,9 +33,11 @@ ESSENTIALS_FILENAME = Path(__file__).parents[0].resolve() / "emnist_essentials.j
 
 
 class EMNIST(BaseDataModule):
-    """
-    "The EMNIST dataset is a set of handwritten character digits derived from the NIST Special Database 19
-    and converted to a 28x28 pixel image format and dataset structure that directly matches the MNIST dataset."
+    """Lightning DataModule class for loading EMNIST dataset.
+
+    'The EMNIST dataset is a set of handwritten character digits derived from the NIST
+    Special Database 19 and converted to a 28x28 pixel image format and dataset structure
+    that directly matches the MNIST dataset.'
     From https://www.nist.gov/itl/iad/image-group/emnist-dataset
 
     The data split we will use is
@@ -56,10 +58,12 @@ class EMNIST(BaseDataModule):
         self.output_dims = (1,)
 
     def prepare_data(self) -> None:
+        """Downloads dataset if not present."""
         if not PROCESSED_DATA_FILENAME.exists():
             download_and_process_emnist()
 
     def setup(self, stage: str = None) -> None:
+        """Loads the dataset specified by the stage."""
         if stage == "fit" or stage is None:
             with h5py.File(PROCESSED_DATA_FILENAME, "r") as f:
                 self.x_train = f["x_train"][:]
@@ -81,22 +85,32 @@ class EMNIST(BaseDataModule):
             )
 
     def __repr__(self) -> str:
-        basic = f"EMNIST Dataset\nNum classes: {len(self.mapping)}\nMapping: {self.mapping}\nDims: {self.dims}\n"
+        """Returns string with info about the dataset."""
+        basic = (
+            "EMNIST Dataset\n"
+            f"Num classes: {len(self.mapping)}\n"
+            f"Mapping: {self.mapping}\n"
+            f"Dims: {self.dims}\n"
+        )
         if not any([self.data_train, self.data_val, self.data_test]):
             return basic
 
         datum, target = next(iter(self.train_dataloader()))
         data = (
-            f"Train/val/test sizes: {len(self.data_train)}, {len(self.data_val)}, {len(self.data_test)}\n"
-            f"Batch x stats: {(datum.shape, datum.dtype, datum.min(), datum.mean(), datum.std(), datum.max())}\n"
-            f"Batch y stats: {(target.shape, target.dtype, target.min(), target.max())}\n"
+            "Train/val/test sizes: "
+            f"{len(self.data_train)}, {len(self.data_val)}, {len(self.data_test)}\n"
+            "Batch x stats: "
+            f"{(datum.shape, datum.dtype, datum.min())}"
+            f"{(datum.mean(), datum.std(), datum.max())}\n"
+            f"Batch y stats: "
+            f"{(target.shape, target.dtype, target.min(), target.max())}\n"
         )
 
         return basic + data
 
 
 def emnist_mapping(
-    extra_symbols: Optional[Sequence[str]],
+    extra_symbols: Optional[Sequence[str]] = None,
 ) -> Tuple[List, Dict[str, int], List[int]]:
     """Return the EMNIST mapping."""
     if not ESSENTIALS_FILENAME.exists():
@@ -112,12 +126,14 @@ def emnist_mapping(
 
 
 def download_and_process_emnist() -> None:
+    """Downloads and preprocesses EMNIST dataset."""
     metadata = toml.load(METADATA_FILENAME)
     download_dataset(metadata, DL_DATA_DIRNAME)
     _process_raw_dataset(metadata["filename"], DL_DATA_DIRNAME)
 
 
 def _process_raw_dataset(filename: str, dirname: Path) -> None:
+    """Processes the raw EMNIST dataset."""
     logger.info("Unzipping EMNIST...")
     curdir = os.getcwd()
     os.chdir(dirname)
-- 
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