[CodeParrot] Near-deduplication with jaccard similarity

examples/research_projects/codeparrot/README.md

@@ -40,6 +40,7 @@ The source of the dataset is the GitHub dump available on Google's [BigQuery](ht
 The raw dataset contains many duplicates. We deduplicated and filtered the dataset using the heuristics proposed in OpenAI's Codex [paper](https://arxiv.org/abs/2107.03374) and some new ones:
 
 - exact deduplication using each file's hash
+- near deduplication using MinHash and Jaccard similarity. MinHash with a Jaccard threshold (default=0.85) is first used to create duplicate clusters. Then these clusters are then reduced to unique files based on the exact Jaccard similarity. See `deduplicate_dataset` in `minhash_deduplication.py` for a detailed description.
 - filtering files with max line length > 1000
 - filtering files with mean line length > 100
 - fraction of alphanumeric characters < 0.25

examples/research_projects/codeparrot/requirements.txt

@@ -4,4 +4,6 @@ wandb==0.12.0
 tensorboard==2.6.0
 torch==1.11.0
 huggingface-hub==0.1.0
-git+https://github.com/huggingface/accelerate.git@3c45b6f760ad8745be9ebc9bbb26f5b04dea4abe
+git+https://github.com/huggingface/accelerate.git@3c45b6f760ad8745be9ebc9bbb26f5b04dea4abe
+datasketch==1.5.7
+dpu_utils

examples/research_projects/codeparrot/scripts/arguments.py

@@ -157,6 +157,12 @@ class PreprocessingArguments:
         default="lvwerra/codeparrot",
         metadata={"help": "Name or path to the tokenizer."},
     )
+    near_deduplication: Optional[bool] = field(
+        default=False, metadata={"help": "If True, near-duplicate samples are removed."}
+    )
+    jaccard_threshold: Optional[float] = field(
+        default=0.85, metadata={"help": "Jaccard threshold for near-duplicate samples."}
+    )
 
 
 @dataclass

examples/research_projects/codeparrot/scripts/minhash_deduplication.py

@@ -0,0 +1,270 @@
+import json
+import multiprocessing as mp
+import re
+from collections import defaultdict
+from functools import partial
+from typing import Dict, List, Optional, Set, Tuple, Type
+
+from datasets import Dataset
+from tqdm import tqdm
+
+from datasketch import MinHash, MinHashLSH
+from dpu_utils.utils.iterators import ThreadedIterator
+
+
+NON_ALPHA = re.compile("[^A-Za-z_0-9]")
+# parameters used in DuplicationIndex
+MIN_NUM_TOKENS = 10
+NUM_PERM = 256
+
+
+def get_min_hash(tokens: List[str]) -> Optional[MinHash]:
+    """Compute the MinHash of a code snippet."""
+    if len(tokens) < MIN_NUM_TOKENS:
+        return None
+    min_hash = MinHash(num_perm=NUM_PERM)
+    for token in set(tokens):
+        min_hash.update(token.encode())
+    return min_hash
+
+
+def get_tokens(code: str) -> Set[str]:
+    """Tokenize a code snippet."""
+    return set([t for t in NON_ALPHA.split(code) if len(t.strip()) > 0])
+
+
+class DuplicationIndex:
+    def __init__(
+        self,
+        *,
+        duplication_jaccard_threshold: float = 0.85,
+    ):
+        self._duplication_jaccard_threshold = duplication_jaccard_threshold
+        self._num_perm = NUM_PERM
+        self._index = MinHashLSH(threshold=self._duplication_jaccard_threshold, num_perm=self._num_perm)
+
+        self._duplicate_clusters = defaultdict(set)
+
+    def add(self, code_key: Tuple, min_hash: MinHash) -> None:
+        """Add a key to _index (MinHashLSH)
+        the min_hash is used to query closest matches based on the jaccard_threshold.
+        The new key is either added to a existing cluster of one close match,
+        or a new cluster is created. The clusters created in this way, depend on the order of add.
+
+        Args:
+            code_key (Tuple of (index, repo_name, path)):
+                Theoritically any hasbale key. Here we use a tuple to retrieve the information later.
+            min_hash: MinHash of the code_key.
+        """
+        close_duplicates = self._index.query(min_hash)
+        if code_key in self._index.keys:
+            print(f"Duplicate key {code_key}")
+            return
+
+        self._index.insert(code_key, min_hash)
+        if len(close_duplicates) > 0:
+
+            for base_duplicate in close_duplicates:
+                if base_duplicate in self._duplicate_clusters:
+                    self._duplicate_clusters[base_duplicate].add(code_key)
+                    break
+            else:
+                self._duplicate_clusters[close_duplicates[0]].add(code_key)
+
+    def get_duplicate_clusters(self) -> List[List[Dict]]:
+        """Export the duplicate clusters.
+        For each cluster, the first element is the base element of the cluster.
+        The base element has an estimation jaccard similarity higher than the threshold with all the other elements.
+
+        Returns:
+            duplicate_clusters (List[List[Dict]]):
+                List of duplicate clusters.
+        """
+        duplicate_clusters = []
+        for base, duplicates in self._duplicate_clusters.items():
+            cluster = [base] + list(duplicates)
+            # reformat the cluster to be a list of dict
+            cluster = [{"base_index": el[0], "repo_name": el[1], "path": el[2]} for el in cluster]
+            duplicate_clusters.append(cluster)
+        return duplicate_clusters
+
+    def save(self, filepath) -> None:
+        duplicate_clusters = self.get_duplicate_clusters()
+        with open(filepath, "w") as f:
+            json.dump(duplicate_clusters, f)
+
+
+def _compute_min_hash(element):
+    index, data = element
+    min_hash = get_min_hash([t for t in NON_ALPHA.split(data["content"]) if len(t.strip()) > 0])
+    if min_hash is not None:
+        return (index, data["repo_name"], data["path"]), min_hash
+
+
+def minhash_iter(dataset_iterator: Type[Dataset]):
+    with mp.Pool() as pool:
+        for data in pool.imap_unordered(
+            _compute_min_hash,
+            ThreadedIterator(dataset_iterator, max_queue_size=10000),
+            chunksize=100,
+        ):
+            if data is not None:
+                yield data
+
+
+def make_duplicate_clusters(dataset_iterator: Type[Dataset], jaccard_threshold: float):
+    """Find duplicate clusters in the dataset in two steps:
+    1. Compute MinHash for each code snippet. MinHash is a tool for fast jaccard similarity estimation.
+    This step is computed using an asynchronous multiprocessing pool, minhash_iter
+    2. Find duplicate clusters. The computed MinHash is added sequentially to the DuplicationIndex.
+    This step cannot be parallelized. So using asynchronous thread in the previous step helps to speed up the process.
+    """
+    di = DuplicationIndex(duplication_jaccard_threshold=jaccard_threshold)
+
+    for filename, min_hash in tqdm(ThreadedIterator(minhash_iter(enumerate(dataset_iterator)), max_queue_size=100)):
+        di.add(filename, min_hash)
+
+    # Returns a List[Cluster] where Cluster is List[str] with the filenames.
+    return di.get_duplicate_clusters()
+
+
+def jaccard_similarity(code1: str, code2: str) -> float:
+    """Compute the Jaccard similarity of two code snippets."""
+    tokens1 = get_tokens(code1)
+    tokens2 = get_tokens(code2)
+    return len(tokens1 & tokens2) / len(tokens1 | tokens2)
+
+
+_shared_dataset = None
+
+
+def _find_cluster_extremes_shared(cluster, jaccard_threshold):
+    """Find a reduced cluster such that each code in the origin cluster is similar to at least one code in the reduced cluster.
+    Two codes are similar if their Jaccard similarity is above the threshold.
+
+    Args:
+        cluster (List[dict]):
+           cluster is a list of dict, each dict contains the following keys:
+                - base_index
+                - repo_name
+                - path
+            This is a typical output of DuplicationIndex.get_duplicate_clusters()
+        jaccard_threshold (float):
+            threshold for Jaccard similarity.
+            Two codes are similar if their Jaccard similarity is above the threshold.
+
+    Returns:
+        extremes (List[dict]):
+            A reduced representation of the cluster. The field copies is added to each dict.
+            The copies field indicates the number of similar codes in the cluster for a extreme.
+    """
+    extremes = []
+    for element1 in cluster:
+        code1 = _shared_dataset[element1["base_index"]]["content"]
+        for element2 in extremes:
+            code2 = _shared_dataset[element2["base_index"]]["content"]
+            if jaccard_similarity(code1, code2) >= jaccard_threshold:
+                element2["copies"] += 1
+                break
+        else:
+            element1["copies"] = 1
+            extremes.append(element1)
+    return extremes
+
+
+def find_extremes(cluster_list, dataset, jaccard_threshold):
+    """Call the _find_cluster_extremes_shared function in a parallel fashion.
+
+    Args:
+        cluster_list (List[List[Dict]]):
+            each cluster is a list of dicts with the key base_index,
+            referring to the index of the base code in the dataset.
+        dataset (Type[Dataset]):
+            dataset is used to access the content of the code snippets,
+            using the base_index from the cluster_list.
+            dataset is shared between all the processes using a glabal variable (any other way to share the dataset?),
+            otherwise the multi processing is not speeded up.
+        jaccard_threshold (float):
+            the threshold for the jaccard similarity. The default value is 0.85
+
+    Returns:
+        extremes_list (List[Dict]):
+            Each cluster is reduced to extremes.
+            See _find_cluster_extremes_shared for the definition of extremes.
+    """
+    global _shared_dataset
+    _shared_dataset = dataset
+    extremes_list = []
+    f = partial(_find_cluster_extremes_shared, jaccard_threshold=jaccard_threshold)
+    with mp.Pool() as pool:
+        for extremes in tqdm(
+            pool.imap_unordered(
+                f,
+                cluster_list,
+            ),
+            total=len(cluster_list),
+        ):
+            extremes_list.append(extremes)
+    return extremes_list
+
+
+def deduplicate_dataset(
+    dataset: Type[Dataset], jaccard_threshold: float = 0.85
+) -> Tuple[Type[Dataset], List[List[Dict]]]:
+    """Deduplicate the dataset using minhash and jaccard similarity.
+    This function first generate duplicate clusters, then each cluster
+    is reduced to the extremes that are similar to the other elements in the cluster.
+    Codes are called similar if their Jaccard similarity is greater than jaccard_threshold (0.85 default).
+
+    Args:
+        dataset (Type[Dataset]):
+            The dataset to deduplicate.
+        jaccard_threshold (float, default=0.85):
+            jaccard threshold to determine if two codes are similar
+
+    Returns:
+        ds_dedup (Type[Dataset]):
+            The deduplicated dataset.
+        duplicate_clusters (List[List[Dict]]):
+            The list of duplicate clusters.
+            Each cluster is a list of dicts with the following keys:
+            - base_index : int
+                The index of the code in the original dataset.
+            - repo_name : str
+            - path : str
+            - copies : int
+                The number of copies of the code in the cluster. (find_cluster_extremes)
+            - is_extreme : bool
+                Whether the code is an extreme in the cluster.
+            All the codes in the cluster are removed from the dataset except the extremes.
+
+    Example:
+        >>> from datasets import load_dataset
+        >>> from minhash_deduplication import deduplicate_dataset
+        >>> ds = load_dataset("lvwerra/codeparrot-clean", split="train")
+        >>> ds_dedup, duplicate_clusters = deduplicate_dataset(ds, jaccard_threshold=0.85)
+    """
+    duplicate_clusters = make_duplicate_clusters(dataset, jaccard_threshold)
+    duplicate_indices = set(x["base_index"] for cluster in duplicate_clusters for x in cluster)
+    extreme_dict = {}
+    extremes_clusters = find_extremes(duplicate_clusters, dataset, jaccard_threshold)
+    for extremes in extremes_clusters:
+        for element in extremes:
+            extreme_dict[element["base_index"]] = element
+    remove_indices = duplicate_indices - set(extreme_dict.keys())
+    ds_filter = dataset.filter(lambda x, idx: idx not in remove_indices, with_indices=True)
+
+    # update duplicate_clusters
+    for cluster in duplicate_clusters:
+        for element in cluster:
+            element["is_extreme"] = element["base_index"] in extreme_dict
+            if element["is_extreme"]:
+                element["copies"] = extreme_dict[element["base_index"]]["copies"]
+
+    print(f"Original dataset size: {len(dataset)}")
+    print(f"Number of duplicate clusters: {len(duplicate_clusters)}")
+    print(f"Files in duplicate cluster: {len(duplicate_indices)}")
+    print(f"Unique files in duplicate cluster: {len(extreme_dict)}")
+    print(f"Filtered dataset size: {len(ds_filter)}")
+
+    return ds_filter, duplicate_clusters

examples/research_projects/codeparrot/scripts/preprocessing.py

@@ -1,14 +1,17 @@
 import gzip
 import hashlib
+import json
 import multiprocessing
 import os
 import shutil
 import time
+from pathlib import Path
 
 import numpy as np
 from datasets import load_dataset
 
 from arguments import PreprocessingArguments
+from minhash_deduplication import deduplicate_dataset
 from transformers import AutoTokenizer, HfArgumentParser
 
 
@@ -146,7 +149,7 @@ def filter(example, uniques, args):
 def compress_file(file_path):
     """Compress a file with g-zip."""
     with open(file_path, "rb") as f_in:
-        with gzip.open(file_path + ".gz", "wb", compresslevel=6) as f_out:
+        with gzip.open(str(file_path) + ".gz", "wb", compresslevel=6) as f_out:
             shutil.copyfileobj(f_in, f_out)
     os.unlink(file_path)
 
@@ -179,12 +182,29 @@ def compress_file(file_path):
 print(f"Time to filter dataset: {time.time()-t_start:.2f}")
 print(f"Size of filtered dataset: {len(ds_filter)}")
 
+# Deduplicate with minhash and jaccard similarity
+if args.near_deduplication:
+    t_start = time.time()
+    ds_filter, duplicate_clusters = deduplicate_dataset(ds_filter, args.jaccard_threshold)
+    print(f"Time to deduplicate dataset: {time.time()-t_start:.2f}")
+    print(f"Size of deduplicate dataset: {len(ds_filter)}")
+
 # Save data in batches of samples_per_file
-if not os.path.exists(args.output_dir):
-    os.makedirs(args.output_dir)
+output_dir = Path(args.output_dir)
+output_dir.mkdir(exist_ok=True)
+
+# save duplicate_clusters in the output_dir as artifacts
+# not sure it is the right place the save it
+if args.near_deduplication:
+    with open(output_dir / "duplicate_clusters.json", "w") as f:
+        json.dump(duplicate_clusters, f)
+
+data_dir = output_dir / "data"
+data_dir.mkdir(exist_ok=True)
+
 t_start = time.time()
 for file_number, index in enumerate(range(0, len(ds_filter), args.samples_per_file)):
-    file_path = f"{args.output_dir}/file-{file_number+1:012}.json"
+    file_path = str(data_dir / f"file-{file_number+1:012}.json")
     end_index = min(len(ds_filter), index + args.samples_per_file)
     ds_filter.select(list(range(index, end_index))).to_json(file_path)
     compress_file(file_path)

examples/research_projects/codeparrot/scripts/tests/test_deduplicate.py

@@ -0,0 +1,30 @@
+from unittest import TestCase
+
+from datasets import Dataset
+
+from minhash_deduplication import deduplicate_dataset, make_duplicate_clusters
+
+
+def get_dataset():
+    data_dict = {
+        "repo_name": ["test_repo1", "test_repo2", "test_repo3"],
+        "path": ["test_1.py", "test_2.py", "unit_test.py"],
+        "content": ["a " * 20, "a " * 30, "b " * 7],
+    }
+    dataset = Dataset.from_dict(data_dict)
+    return dataset
+
+
+class MakeDuplicateClustersTest(TestCase):
+    def test_make_duplicate_clusters(self):
+        ds = get_dataset()
+        duplicate_clusters = make_duplicate_clusters(ds, 0.85)
+        self.assertEqual(len(duplicate_clusters[0]), 2)
+
+    def test_deduplicate_dataset(self):
+        ds = get_dataset()
+        ds_filter, duplicate_clusters = deduplicate_dataset(ds)
+        self.assertEqual(len(ds_filter), 2)
+        print(duplicate_clusters)
+        self.assertEqual(duplicate_clusters[0][0]["copies"], 2)
+        self.assertEqual(duplicate_clusters[0][0]["is_extreme"], True)