Add new document to passage splitting mechanism

Author: Thejas Venkatesh

utility/preprocess/docs2passages.py

@@ -29,10 +29,18 @@ def process_page(inp):
     else:
         words = tokenizer.tokenize(content)
 
-    words_ = (words + words) if len(words) > nwords else words
-    passages = [words_[offset:offset + nwords] for offset in range(0, len(words) - overlap, nwords - overlap)]
-
-    assert all(len(psg) in [len(words), nwords] for psg in passages), (list(map(len, passages)), len(words))
+    n_passages = (len(words) + nwords - 1) // nwords
+    if n_passages > 1:
+        last_2_passage_length = len(words) - nwords * (n_passages - 2)
+        passage_lengths = [0] + [nwords] * (n_passages - 2) + [last_2_passage_length // 2] + [last_2_passage_length - last_2_passage_length // 2]
+        assert sum(passage_lengths) == len(words)
+    elif n_passages == 1:
+        passage_lengths = [0, len(words)]
+    else:
+        passage_lengths = [0]
+    print(n_passages, passage_lengths)
+    assert len(passage_lengths) == n_passages + 1
+    passages = [words[passage_lengths[idx-1]:passage_lengths[idx]] for idx in range(1, len(passage_lengths))]
 
     if tokenizer is None:
         passages = [' '.join(psg) for psg in passages]

utility/preprocess/docs2passages_dpr.py

@@ -0,0 +1,149 @@
+"""
+    Divide a document collection into N-word/token passage spans (with wrap-around for last passage).
+"""
+
+import os
+import math
+import ujson
+import random
+
+from multiprocessing import Pool
+from argparse import ArgumentParser
+from colbert.utils.utils import print_message
+
+Format1 = 'docid,text'  # MS MARCO Passages
+Format2 = 'docid,text,title'   # DPR Wikipedia
+Format3 = 'docid,url,title,text'  # MS MARCO Documents
+
+
+def process_page(inp):
+    """
+        Wraps around if we split: make sure last passage isn't too short.
+        This is meant to be similar to the DPR preprocessing.
+    """
+
+    (nwords, overlap, tokenizer), (title_idx, docid, title, url, content) = inp
+
+    if tokenizer is None:
+        words = content.split()
+    else:
+        words = tokenizer.tokenize(content)
+
+    words_ = (words + words) if len(words) > nwords else words
+    passages = [words_[offset:offset + nwords] for offset in range(0, len(words) - overlap, nwords - overlap)]
+
+    assert all(len(psg) in [len(words), nwords] for psg in passages), (list(map(len, passages)), len(words))
+
+    if tokenizer is None:
+        passages = [' '.join(psg) for psg in passages]
+    else:
+        passages = [' '.join(psg).replace(' ##', '') for psg in passages]
+
+    if title_idx % 100000 == 0:
+        print("#> ", title_idx, '\t\t\t', title)
+
+        for p in passages:
+            print("$$$ ", '\t\t', p)
+            print()
+
+        print()
+        print()
+        print()
+
+    return (docid, title, url, passages)
+
+
+def main(args):
+    random.seed(12345)
+    print_message("#> Starting...")
+
+    letter = 'w' if not args.use_wordpiece else 't'
+    output_path = f'{args.input}.{letter}{args.nwords}_{args.overlap}'
+    assert not os.path.exists(output_path)
+
+    RawCollection = []
+    Collection = []
+
+    NumIllFormattedLines = 0
+
+    with open(args.input) as f:
+        for line_idx, line in enumerate(f):
+            if line_idx % (100*1000) == 0:
+                print(line_idx, end=' ')
+
+            title, url = None, None
+
+            try:
+                line = line.strip().split('\t')
+
+                if args.format == Format1:
+                    docid, doc = line
+                elif args.format == Format2:
+                    docid, doc, title = line
+                elif args.format == Format3:
+                    docid, url, title, doc = line
+
+                RawCollection.append((line_idx, docid, title, url, doc))
+            except:
+                NumIllFormattedLines += 1
+
+                if NumIllFormattedLines % 1000 == 0:
+                    print(f'\n[{line_idx}] NumIllFormattedLines = {NumIllFormattedLines}\n')
+
+    print()
+    print_message("# of documents is", len(RawCollection), '\n')
+
+    p = Pool(args.nthreads)
+
+    print_message("#> Starting parallel processing...")
+
+    tokenizer = None
+    if args.use_wordpiece:
+        from transformers import BertTokenizerFast
+        tokenizer = BertTokenizerFast.from_pretrained('bert-base-uncased')
+
+    process_page_params = [(args.nwords, args.overlap, tokenizer)] * len(RawCollection)
+    Collection = p.map(process_page, zip(process_page_params, RawCollection))
+
+    print_message(f"#> Writing to {output_path} ...")
+    with open(output_path, 'w') as f:
+        line_idx = 1
+
+        if args.format == Format1:
+            f.write('\t'.join(['id', 'text']) + '\n')
+        elif args.format == Format2:
+            f.write('\t'.join(['id', 'text', 'title']) + '\n')
+        elif args.format == Format3:
+            f.write('\t'.join(['id', 'text', 'title', 'docid']) + '\n')
+
+        for docid, title, url, passages in Collection:
+            for passage in passages:
+                if args.format == Format1:
+                    f.write('\t'.join([str(line_idx), passage]) + '\n')
+                elif args.format == Format2:
+                    f.write('\t'.join([str(line_idx), passage, title]) + '\n')
+                elif args.format == Format3:
+                    f.write('\t'.join([str(line_idx), passage, title, docid]) + '\n')
+
+                line_idx += 1
+
+
+if __name__ == "__main__":
+    parser = ArgumentParser(description="docs2passages.")
+
+    # Input Arguments.
+    parser.add_argument('--input', dest='input', required=True)
+    parser.add_argument('--format', dest='format', required=True, choices=[Format1, Format2, Format3])
+
+    # Output Arguments.
+    parser.add_argument('--use-wordpiece', dest='use_wordpiece', default=False, action='store_true')
+    parser.add_argument('--nwords', dest='nwords', default=100, type=int)
+    parser.add_argument('--overlap', dest='overlap', default=0, type=int)
+
+    # Other Arguments.
+    parser.add_argument('--nthreads', dest='nthreads', default=28, type=int)
+
+    args = parser.parse_args()
+    assert args.nwords in range(50, 500)
+
+    main(args)