Merge branch 'lmcafee/retro' into 'main'

Retro

See merge request ADLR/megatron-lm!489

tools/retro/examples/pretrain_model.sh

+#!/bin/bash
+
+##################################################
+# Example script for pretraining Retro.
+##################################################
+
+set -u
+unset NCCL_DEBUG
+export CUDA_DEVICE_MAX_CONNECTIONS=1
+
+NPROCS=8 # NPROCS must be <= number of GPUs.
+
+################ Dataset configs. ################
+# This script contains methods to customize arguments to specific dataset
+# types. Customize this script as needed for your datasets.
+DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+. $DIR/get_dataset_configs.sh
+
+################ Environment variables. ################
+# *Note*: See 'Required environment variables' in 'get_preprocess_cmd.sh' for
+# a description of the required environment variables. These variables can be
+# set however a user would like. In our setup, we use another bash script
+# (location defined by $RETRO_ENV_VARS) that sets all the environment variables
+# at once.
+. $RETRO_ENV_VARS
+
+################ Data blend. ################
+. ${DATA_BLEND_SCRIPT}
+DATA_PATH=${DATA_BLEND}
+
+######## Retro setup. ########
+RETRO_ADD_RETRIEVER=1
+RETRO_CYCLIC_TRAIN_ITERS=750000
+RETRO_NUM_NEIGHBORS=2
+
+######## Arguments. ########
+CHECKPOINT_DIR=${RETRO_WORKDIR}/checkpoints/${RETRO_ADD_RETRIEVER}
+TENSORBOARD_DIR="${CHECKPOINT_DIR}/tensorboard"
+mkdir -p ${TENSORBOARD_DIR}
+ARGS=" \
+    --save-interval 1000 \
+    --save ${CHECKPOINT_DIR} \
+    --load ${CHECKPOINT_DIR} \
+    --tensorboard-dir ${TENSORBOARD_DIR} \
+    --log-interval 5 \
+    --tensor-model-parallel-size 1 \
+    --pipeline-model-parallel-size 1 \
+    --num-layers 12 \
+    --hidden-size 768 \
+    --num-attention-heads 12 \
+    --seq-length 2048 \
+    --max-position-embeddings 2048 \
+    --micro-batch-size 4 \
+    --global-batch-size 256 \
+    --train-samples ${RETRO_GPT_TRAIN_SAMPLES}  \
+    --lr-decay-samples ${LR_DECAY_SAMPLES} \
+    --lr-warmup-samples ${LR_WARMUP_SAMPLES} \
+    --lr 6.0e-4 \
+    --min-lr 6.0e-5 \
+    --lr-decay-style cosine \
+    --eval-interval ${RETRO_GPT_EVAL_INTERVAL} \
+    --eval-iters ${RETRO_GPT_EVAL_ITERS} \
+    --data-path ${DATA_PATH} \
+    --vocab-file ${GPT_VOCAB_FILE} \
+    --merge-file ${GPT_MERGE_FILE} \
+    --split 98,2,0 \
+    --clip-grad 1.0 \
+    --weight-decay 0.1 \
+    --adam-beta1 0.9 \
+    --adam-beta2 0.95 \
+    --init-method-std 0.023 \
+    --log-params-norm \
+    --log-num-zeros-in-grad \
+    --fp16 \
+    --DDP-impl local \
+    --dataloader-type ${DATALOADER_TYPE} \
+    --no-data-sharding \
+    --no-gradient-accumulation-fusion \
+"
+
+if [ "$RETRO_ADD_RETRIEVER" = "0" ]; then
+    SCRIPT=pretrain_gpt.py
+else
+    ARGS="${ARGS} \
+    --retro-add-retriever \
+    --retro-workdir ${RETRO_WORKDIR} \
+    --retro-cyclic-train-iters ${RETRO_CYCLIC_TRAIN_ITERS} \
+    --retro-num-neighbors ${RETRO_NUM_NEIGHBORS} \
+    "
+    SCRIPT=pretrain_retro.py
+fi
+
+echo "~~~~~~~~~~~~~~~~~~~~~~~~~~"
+echo "ARGS = '$ARGS'."
+echo "~~~~~~~~~~~~~~~~~~~~~~~~~~"
+
+python -m torch.distributed.launch \
+    --nproc_per_node ${NPROCS} \
+    --nnodes 1 \
+    --node_rank 0 \
+    --master_addr localhost \
+    --master_port 6000 \
+    ${SCRIPT} \
+    ${ARGS} \

tools/retro/external_libs.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+import importlib
+
+required_libs = [
+    "faiss",
+    "h5py",
+    "transformers", # for huggingface bert
+]
+
+for lib in required_libs:
+    try:
+        globals()[lib] = importlib.import_module(lib)
+    except ImportError as e:
+        raise Exception(f"Missing one or more packages required for Retro preprocessing: {required_libs}. Tried importing '{lib}'.")

tools/retro/index/__init__.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+from .index import Index

tools/retro/index/build.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+import numpy as np
+import os
+import shutil
+import torch
+from tqdm import tqdm
+
+from megatron import get_retro_args, print_rank_0
+from tools.bert_embedding import DiskDataParallelBertEmbedder
+from tools.retro.db.utils import (
+    get_indexed_dataset_infos,
+    get_merged_sampled_dataset,
+    get_merged_train_dataset,
+)
+from tools.retro.external_libs import h5py
+from tools.retro.index.factory import IndexFactory
+from tools.retro.utils import GPTToTextDataset
+
+from .utils import (
+    get_training_data_dir,
+    get_training_data_merged,
+)
+
+
+##################################################
+# Train index.
+##################################################
+
+
+def get_empty_index_path():
+    '''Path of empty index.'''
+    args = get_retro_args()
+    index = IndexFactory.get_index(args.retro_index_type)
+    empty_index_path = index.get_empty_index_path()
+    return empty_index_path
+
+
+def embed_db():
+    '''Embed DB chunks.
+
+    Store chunks in blocks on disk. These blocks will later be merged into
+    a single dataset for training the index.
+    '''
+
+    args = get_retro_args()
+
+    # Get db dataset.
+    gpt_dataset = get_merged_sampled_dataset()
+    text_dataset = GPTToTextDataset(gpt_dataset)
+
+    # Embed dataset.
+    embedder = DiskDataParallelBertEmbedder(args.retro_bert_batch_size,
+                                            args.retro_bert_max_chunk_length,
+                                            args.retro_block_size,
+                                            args.bert_embedder_type)
+    embedder.embed_text_dataset("index", get_training_data_dir(), text_dataset)
+
+
+def train_on_embeddings():
+    '''Train index on embedded DB chunks.'''
+    args = get_retro_args()
+    index = IndexFactory.get_index(args.retro_index_type)
+    index.train(get_training_data_merged)
+
+
+def remove_embeddings():
+    '''Remove embeddings after training.'''
+    torch.distributed.barrier()
+    if torch.distributed.get_rank() != 0:
+        return
+    empty_index_path = get_empty_index_path()
+    assert os.path.isfile(empty_index_path)
+    shutil.rmtree(get_training_data_dir(), ignore_errors=True)
+
+
+def train_index():
+    '''Train index on DB chunks.'''
+
+    args = get_retro_args()
+
+    # Check if trained index already exists.
+    if not os.path.isfile(get_empty_index_path()):
+
+        # Embed training chunks.
+        embed_db()
+
+        # Train index on embeddings.
+        train_on_embeddings()
+
+    # Wait for (single-process) training to complete.
+    torch.distributed.barrier()
+
+    # Remove embeddings.
+    if args.retro_delete_index_training_embeddings:
+        remove_embeddings()
+
+
+##################################################
+# Add to index.
+##################################################
+
+
+def add_to_index():
+    '''Add DB chunks to index.'''
+
+    args = get_retro_args()
+
+    # Get index.
+    index = IndexFactory.get_index(args.retro_index_type)
+
+    # Get text dataset.
+    gpt_dataset = get_merged_train_dataset()
+    text_dataset = GPTToTextDataset(gpt_dataset)
+
+    # Add to index.
+    output_index_path = index.add(text_dataset)
+
+    return output_index_path
+
+
+##################################################
+# Build index (train + add).
+##################################################
+
+
+def build_index():
+    '''Build index.
+
+    Building index involves sequentially running stages above:
+    - Train index (on sampled training chunks).
+    - Add to index (on all training chunks).
+    '''
+
+    # Train index.
+    train_index()
+
+    # Add to index.
+    add_to_index()

tools/retro/index/factory.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+from .indexes import FaissBaseIndex, FaissParallelAddIndex
+
+
+class IndexFactory:
+    '''Get index.
+
+    Index type generally read from argument '--retro-index-ty'.
+    '''
+
+    @classmethod
+    def get_index_class(cls, index_type):
+        return {
+            "faiss-base" : FaissBaseIndex,
+            "faiss-par-add" : FaissParallelAddIndex,
+        }[index_type]
+
+    @classmethod
+    def get_index(cls, index_type):
+        index_class = cls.get_index_class(index_type)
+        index = index_class()
+        return index

tools/retro/index/index.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+import abc
+import numpy as np
+import os
+import torch
+
+from tools.retro.external_libs import faiss
+
+from .utils import get_index_dir
+
+
+class Index(abc.ABC):
+
+    '''Abstract base class for indexes.
+
+    *Note* : While currently only Faiss-based classes are implemented, in the
+    future, this class will be extended with other types of indexes that have
+    different performance-accuracy trade-offs.
+
+    The primary methods to override are:
+    - train() : Train index on the sampled training chunks.
+    - add() : Add all training chunks to index.
+    '''
+
+    @classmethod
+    def c_verbose(cls, index, v):
+        '''Make index object verbose.'''
+        assert isinstance(v, bool)
+        faiss.ParameterSpace().set_index_parameter(index, "verbose", v)
+
+    def get_empty_index_path(self):
+        return os.path.join(get_index_dir(), "empty.faissindex")
+
+    def get_empty_index(self):
+        return faiss.read_index(self.get_empty_index_path())
+
+    def get_added_index_path(self):
+        return os.path.join(get_index_dir(), "added.faissindex")
+
+    def get_added_index(self):
+        return faiss.read_index(self.get_added_index_path())
+
+    @abc.abstractmethod
+    def train(self, *args):
+        pass
+
+    @abc.abstractmethod
+    def add(self, *args):
+        pass
+
+    def embed_text_dataset_block(self, embedder, text_dataset, _range):
+        '''Embed a range of a text dataset.'''
+        sub_dataset = torch.utils.data.Subset(text_dataset, range(*_range))
+        return embedder.embed_text_dataset(sub_dataset)

tools/retro/index/indexes/__init__.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+from .faiss_base import FaissBaseIndex
+from .faiss_par_add import FaissParallelAddIndex

tools/retro/index/indexes/faiss_base.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+"""
+This class implements a simple, un-optimized wrapper around a Faiss index, that
+implements the Index interface (see ..index.py). While this class is
+instantiable, it is meant to be extended with optimizations in classes that
+inherit from this class (see FaissParAddIndex, for an example).
+"""
+
+from datetime import timedelta
+import os
+import torch
+from tqdm import tqdm
+
+from megatron import get_retro_args, print_rank_0
+from tools.bert_embedding import BertEmbedder
+from tools.retro.external_libs import faiss
+from tools.retro.index import Index
+from tools.retro.index.utils import num_samples_to_block_ranges
+
+
+class FaissBaseIndex(Index):
+
+    def _train(self, input_data_loader):
+        '''Train index (rank 0's method).'''
+
+        args = get_retro_args()
+
+        assert torch.distributed.get_rank() == 0
+
+        # Set num threads (torch.distributed reset it to 1).
+        # faiss.omp_set_num_threads(32)
+        faiss.omp_set_num_threads(64)
+        # faiss.omp_set_num_threads(128)
+
+        empty_index_path = self.get_empty_index_path()
+
+        # Index already exists? -> return.
+        if os.path.isfile(empty_index_path):
+            return
+
+        # Load data.
+        inp = input_data_loader()
+
+        # Init index.
+        index = faiss.index_factory(args.retro_index_nfeats,
+                                    args.retro_index_str)
+
+        # Move to GPU.
+        index_ivf = faiss.extract_index_ivf(index)
+        clustering_index = \
+            faiss.index_cpu_to_all_gpus(faiss.IndexFlatL2(index_ivf.d))
+        index_ivf.clustering_index = clustering_index
+        self.c_verbose(index, True)
+        self.c_verbose(index_ivf, True)
+        self.c_verbose(index_ivf.quantizer, True)
+        self.c_verbose(index_ivf.clustering_index, True)
+
+        # Train index.
+        index.train(inp)
+
+        # Save index.
+        faiss.write_index(index, empty_index_path)
+
+    def train(self, input_data_loader):
+        '''Train index.'''
+
+        # Single process only.
+        if torch.distributed.get_rank() == 0:
+            self._train(input_data_loader)
+
+        torch.distributed.barrier()
+
+    def _add(self, text_dataset):
+        '''Add to index (rank 0's method).'''
+
+        assert torch.distributed.get_rank() == 0
+
+        args = get_retro_args()
+
+        dataset_sample_ranges = num_samples_to_block_ranges(len(text_dataset))
+
+        # Set num threads (torch.distributed reset it to 1).
+        faiss.omp_set_num_threads(64)
+
+        # Bert embedder.
+        embedder = BertEmbedder(args.retro_bert_batch_size,
+                                args.retro_bert_max_chunk_length,
+                                args.bert_embedder_type)
+
+        # Empty/added index paths.
+        empty_index_path = self.get_empty_index_path()
+        added_index_path = self.get_added_index_path()
+
+        # Skip adding, if index exists.
+        if os.path.isfile(added_index_path):
+            return
+
+        # Read trained index.
+        index = faiss.read_index(empty_index_path)
+
+        # Iterate data blocks & add.
+        for sample_range in tqdm(dataset_sample_ranges, "faiss_base.add"):
+
+            # Embed text.
+            embeds = self.embed_text_dataset_block(
+                embedder, text_dataset, sample_range)
+
+            # Add to index.
+            index.add(embeds)
+
+        # Write index.
+        faiss.write_index(index, added_index_path)
+
+    def add(self, text_dataset):
+        '''Add to index.'''
+
+        # Single process only.
+        if torch.distributed.get_rank() == 0:
+            self._add(text_dataset)
+
+        # Wait for rank 0.
+        torch.distributed.barrier()
+
+        # Get output index path, for return.
+        return self.get_added_index_path()

tools/retro/index/indexes/faiss_par_add.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+"""Multi-process & multi-node version of Faiss's index.add().
+
+This class inherits from FaissBaseIndex, and optimizes the 'add()' method by
+making it multi-node and multi-process, with bit-wise equivalence to
+FaissBaseIndex. This allows 'add()' to scale out to very large datasets, since
+the vast majority of the computational effort is embarrassingly parallel.
+"""
+
+import numpy as np
+import os
+import shutil
+import torch
+from tqdm import tqdm
+
+from megatron import get_retro_args, print_rank_0
+from tools.bert_embedding import BertEmbedder
+from tools.bert_embedding.utils import get_missing_blocks_by_rank
+from tools.retro.external_libs import faiss, h5py
+from tools.retro.index.utils import get_added_codes_dir, get_added_code_paths
+
+from .faiss_base import FaissBaseIndex
+
+
+class FaissParallelAddIndex(FaissBaseIndex):
+
+    def encode_block(self, index, embedder, text_dataset, block):
+        '''Encode sub-dataset block, to be later added to index.
+
+        Encode the data subset, generally in blocks of 1M vectors each. For
+        each block, the empty/trained index is loaded, codes are computed
+        via index.sa_encode(), and the resulting codes are saved to disk.
+        '''
+
+        args = get_retro_args()
+
+        # Embed block.
+        embeddings = self.embed_text_dataset_block(
+            embedder,
+            text_dataset,
+            block["range"],
+        )
+
+        # Encode block.
+        print_rank_0("encode.")
+        codes = index.sa_encode(embeddings)
+
+        # Save neighbors.
+        print_rank_0("save codes.")
+        os.makedirs(os.path.dirname(block["path"]), exist_ok=True)
+        with h5py.File(block["path"], "w") as f:
+            f.create_dataset("data", data=codes)
+
+    def encode(self, text_dataset):
+        '''Encode text dataset, to be later added to index.'''
+
+        args = get_retro_args()
+        codes_dir = get_added_codes_dir()
+
+        # Index.
+        index = self.get_empty_index()
+
+        # Bert embedder.
+        embedder = BertEmbedder(args.retro_bert_batch_size,
+                                args.retro_bert_max_chunk_length,
+                                args.bert_embedder_type)
+
+        # Missing code blocks.
+        def validate(f):
+            assert len(f["data"].shape) == 2
+        n_missing_blocks, missing_code_blocks = get_missing_blocks_by_rank(
+            codes_dir,
+            len(text_dataset),
+            args.retro_block_size,
+            validate=validate,
+        )
+
+        # Encode each block.
+        for block_index, block in enumerate(missing_code_blocks):
+
+            if block is not None:
+
+                # Progress.
+                print_rank_0("encode block %d / %d ... %s." % (
+                    block_index,
+                    len(missing_code_blocks),
+                    block["path"],
+                ))
+
+                # Query block neighbors.
+                self.encode_block(index, embedder, text_dataset, block)
+
+            # Synchronize progress across all ranks. (for easier observation)
+            print_rank_0(" > waiting for other ranks to finish block.")
+            torch.distributed.barrier()
+
+    def add_codes(self):
+
+        if torch.distributed.get_rank() != 0:
+            return
+
+        added_index_path = self.get_added_index_path()
+        if os.path.exists(added_index_path):
+            return
+
+        # Index.
+        print_rank_0("read empty index.")
+        index = self.get_empty_index()
+        index_ivf = faiss.extract_index_ivf(index)
+
+        # Add codes.
+        print_rank_0("add codes.")
+        code_paths = get_added_code_paths()
+        for code_path in tqdm(code_paths, "add codes"):
+            with h5py.File(code_path) as f:
+                codes = np.copy(f["data"])
+                index_ivf.add_sa_codes(codes)
+
+        # Update index's ntotal.
+        index.ntotal = index_ivf.ntotal
+
+        # Write index.
+        print_rank_0("write added index.")
+        faiss.write_index(index, added_index_path)
+
+    def remove_codes(self):
+        '''Remove added codes after adding to index.'''
+        if torch.distributed.get_rank() != 0:
+            return
+        assert os.path.isfile(self.get_added_index_path())
+        shutil.rmtree(get_added_codes_dir(), ignore_errors=True)
+
+    def add(self, text_dataset):
+
+        # Check if index already exists.
+        if not os.path.isfile(self.get_added_index_path()):
+
+            # Encode chunks.
+            self.encode(text_dataset)
+
+            # Add codes to index.
+            self.add_codes()
+
+        # Wait for (single-process) adding to complete.
+        torch.distributed.barrier()
+
+        # Remove codes.
+        self.remove_codes()

tools/retro/index/utils.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+import concurrent
+import gc
+import glob
+import numpy as np
+import os
+import psutil
+import time
+import torch
+from tqdm import tqdm
+
+from megatron import get_retro_args, print_rank_0
+from tools.retro.db.utils import get_indexed_dataset_infos
+from tools.retro.external_libs import h5py
+
+
+def get_index_dir():
+    """Create sub-directory for this index."""
+
+    args = get_retro_args()
+
+    # Directory path.
+    index_dir_path = os.path.join(
+        args.retro_workdir,
+        "index",
+        args.retro_index_type,
+        args.retro_index_str,
+    )
+
+    # Make directory.
+    os.makedirs(index_dir_path, exist_ok=True)
+
+    return index_dir_path
+
+
+def num_samples_to_block_ranges(num_samples):
+    '''Split a range (length num_samples) into sequence of block ranges
+    of size block_size.'''
+    args = get_retro_args()
+    block_size = args.retro_block_size
+    start_idxs = list(range(0, num_samples, block_size))
+    end_idxs = [min(num_samples, s + block_size) for s in start_idxs]
+    ranges = list(zip(start_idxs, end_idxs))
+    return ranges
+
+
+def get_training_data_dir():
+    return os.path.join(get_index_dir(), "train_tmp")
+
+
+def get_training_data_paths():
+    return sorted(glob.glob(get_training_data_dir() + "/*.hdf5"))
+
+
+def get_added_codes_dir():
+    return os.path.join(get_index_dir(), "add_tmp")
+
+
+def get_added_code_paths():
+    return sorted(glob.glob(get_added_codes_dir() + "/*.hdf5"))
+
+
+def get_training_data_group_infos():
+
+    args = get_retro_args()
+
+    block_paths = get_training_data_paths()
+    max_group_size = args.retro_index_train_block_size
+
+    groups = []
+    group = []
+    group_size = 0
+    for block_path in block_paths:
+        with h5py.File(block_path) as f:
+            block_size = f["data"].shape[0]
+        group.append(block_path)
+        group_size += block_size
+
+        if group_size >= max_group_size:
+            groups.append({
+                "paths" : group,
+                "size" : group_size,
+            })
+            group = []
+            group_size = 0
+    if group:
+        groups.append({
+            "paths" : group,
+            "size" : group_size,
+        })
+
+    return groups
+
+
+def load_training_block(path, load_fraction):
+    with h5py.File(path) as f:
+        n_load = int(load_fraction * f["data"].shape[0])
+        return np.copy(f["data"][:n_load])
+
+
+def load_training_group(executor, group_info, load_fraction):
+
+    # Launch threads to load block data.
+    futures = []
+    for path in group_info["paths"]:
+        futures.append(executor.submit(load_training_block, path, load_fraction))
+
+    # Collect block data.
+    block_datas = []
+    for future in futures:
+        block_datas.append(future.result())
+
+    # Concatenate blocks.
+    group_data = np.concatenate(block_datas, axis=0)
+
+    # Garbage collect.
+    for d in block_datas:
+        del d
+    gc.collect()
+
+    return group_data
+
+
+def get_training_data_merged():
+    '''Merge embeddings into single dataset.'''
+
+    args = get_retro_args()
+
+    # Setup.
+    ds_infos = get_indexed_dataset_infos()
+    n_chunks_sampled = sum(d["n_chunks_sampled"] for d in ds_infos)
+    load_fraction = args.retro_index_train_load_fraction
+
+    # Initialize merged data.
+    print("allocate training data array.")
+    t = time.time()
+    data = np.empty((n_chunks_sampled, args.retro_index_nfeats), dtype="f4")
+    print("  time : %.3f sec." % (time.time() - t))
+
+    # Data groups (minimizing fragmentation).
+    group_infos = get_training_data_group_infos()
+
+    # Load data blocks.
+    n_threads = max(len(group["paths"]) for group in group_infos)
+    with concurrent.futures.ThreadPoolExecutor(max_workers=n_threads) as executor:
+
+        # Load data blocks.
+        print("load training data blocks.")
+        start_idx = 0
+        pbar = tqdm(group_infos)
+        for group_info in pbar:
+
+            pbar.set_description("mem %.0f gb, %.1f%%" % (
+                psutil.virtual_memory()[3] / 1024**3,
+                psutil.virtual_memory()[2],
+            ))
+
+            # Load group data.
+            group_data = load_training_group(executor, group_info, load_fraction)
+            data[start_idx:(start_idx+len(group_data))] = group_data
+            start_idx += len(group_data)
+
+            # Garbage collect.
+            del group_data
+            gc.collect()
+
+        # Handle load ratio <1.
+        data = data[:start_idx]
+        print("> training block data.shape = %s." % str(data.shape))
+
+    return data

tools/retro/main.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+"""Preprocess data for Retro.
+
+Stages (see argument '--retro-tasks'):
+- Build chunk database (DB).
+- Build index (train, add).
+- Query pretraining neighbors.
+"""
+
+import json
+import os
+import torch
+
+from megatron import get_args, initialize_megatron, print_rank_0
+from megatron.global_vars import set_retro_args
+from tools.retro.db import build_db
+from tools.retro.index.build import add_to_index, build_index, train_index
+from tools.retro.pretraining.query import query_pretraining_neighbors
+from tools.retro.utils import get_args_path
+
+
+def add_retro_args(parser):
+    """Retro preprocesing arguments.
+
+    *Note* : Arguments prefixed with '--retro-gpt-*' or '--retro-bert-*' are
+    included and named as such to more easily handle managing both models
+    running at the same time. Megatron is not optimized to run two models at
+    once, so this naming convention makes it clearer.
+    """
+
+    group = parser.add_argument_group(title="Retro preprocessing.")
+
+    group.add_argument("--retro-gpt-vocab-file", required=True,
+                       help="GPT vocab file.")
+    group.add_argument("--retro-gpt-merge-file", required=True,
+                       help="GPT merge file.")
+    group.add_argument("--retro-gpt-tokenizer-type", required=True,
+                       help="GPT tokenizer type.")
+    group.add_argument("--retro-gpt-seq-length", type=int, default=2048,
+                       help="GPT sequence length.")
+    group.add_argument("--retro-gpt-chunk-length", type=int, default=64,
+                       help="GPT chunk length.")
+    group.add_argument("--retro-bert-vocab-file", required=True,
+                       help="Bert vocab file.")
+    group.add_argument("--retro-bert-tokenizer-type", required=True,
+                       help="Bert tokenizer type (for when using "
+                       "'--bert-embedder-type megatron').")
+    group.add_argument("--retro-bert-batch-size", type=int, default=128,
+                       help="Micro-batch size for processing Bert embeddings.")
+    group.add_argument("--retro-bert-max-chunk-length", type=int, default=256,
+                       help="Maximum sequence length for Bert embeddings. "
+                       "(Named 'chunk' here in reference to these Bert "
+                       "sequences being converted from GPT chunks.)")
+    group.add_argument("--retro-tasks", default="build",
+                       help="Comma-separated list of tasks to run. Run entire "
+                       "preprocesing pipeline by using '--retro-tasks build'. "
+                       "Alternatively, run individual stages with tasks (in "
+                       "this order) 'db-build', 'index-build', or "
+                       "'pretraining-query-neighbors'. For example, "
+                       "'--retro-tasks db-build,index-build,"
+                       "pretraining-query-neighbors' is equivalent to "
+                       "'--retro-tasks build'; or the argument can contain "
+                       "a subset of these tasks. Stages must always be run "
+                       "in the correct order (listed above).")
+    group.add_argument("--retro-index-nfeats", "-f", type=int, default=1024,
+                       help="Dimension of Bert embeddings. Bert-large is "
+                       "commonly used, so this value defaults to 1024.")
+    group.add_argument("--retro-index-type", default="faiss-par-add",
+                       choices=["faiss-base", "faiss-par-add"],
+                       help="A 'faiss-base' index is a simple, un-optimized "
+                       "wrapper around a Faiss index. A 'faiss-par-add' index "
+                       "optimizes the 'add()' method by making it multi-node "
+                       "and multi-process, but with bit-wise equivalent "
+                       "results.")
+    group.add_argument("--retro-index-str", required=True,
+                       help="Index string used for calling "
+                       "faiss.index_factory(). For example, "
+                       "'IVF262144_HNSW32,Flat' or "
+                       "'OPQ32_256,IVF4194304_HNSW32,PQ32'.")
+    group.add_argument("--retro-ef-search", type=int, default=256,
+                       help="Index ef-search parameter for HNSW during "
+                       "querying.")
+    group.add_argument("--retro-nprobe", type=int, default=65536,
+                       help="Index nprobe parameter for IVF during "
+                       "querying.")
+    group.add_argument("--retro-nchunks-sampled", type=int, required=True,
+                       help="Number of database chunks to use for training "
+                       "the index. This value must be less or equal to the "
+                       "total number of chunks in the database.")
+    group.add_argument("--retro-doc-block-size", type=int, default=100000,
+                       help="Number of documents to processe at time when "
+                       "processing token datasets into chunk databases. The "
+                       "partial chunk database for each block is saved into "
+                       "a separate file.")
+    group.add_argument("--retro-block-size", type=int, default=100000,
+                       help="Number of chunks to process at a time when "
+                       "generating Bert embeddings and querying the search "
+                       "index. Partial results for each block are generally "
+                       "saved to disk in separate files.")
+    group.add_argument("--retro-index-train-block-size",
+                       type=int, default=3750000,
+                       help="As a memory fragmentation optimization, when "
+                       "loading training data for training the search index, "
+                       "enough data blocks loaded at a time until they reach "
+                       "retro_index_train_block_size, and then this "
+                       "data block is copied into the full training data "
+                       "array.")
+    group.add_argument("--retro-index-train-load-fraction",
+                       type=float, default=1.,
+                       help="Fraction of sampled chunks to use for training "
+                       "the index. Useful when our total sampled embeddings "
+                       "use too much memory; lowering the load fraction is "
+                       "less costly than re-embedding a new sampled dataset "
+                       "from scratch.")
+    group.add_argument("--retro-num-neighbors-query", type=int, default=2000,
+                       help="Number of neighbors to retrieve when calling "
+                       "index.search().")
+    group.add_argument("--retro-num-neighbors-target", type=int, default=200,
+                       help="Number of neighbors to save to disk after "
+                       "the index's returned neighbors. If longer than target "
+                       "value, neighbors truncated; and if shorter than target "
+                       "value, neighbors are padded with -1's.")
+    group.add_argument("--retro-no-delete-index-training-embeddings",
+                       action='store_false',
+                       dest="retro_delete_index_training_embeddings",
+                       help="Skip deleting training embeddings for the search "
+                       "index. Useful for debugging.")
+
+    # Enforce argument naming convention.
+    for action in group._group_actions:
+        prefix = action.dest.split("_")[0]
+        assert prefix == "retro", \
+            "Retro args must be prefixed with '--retro-*', for consistent " \
+            "styling. Please fix '%s'." % ", ".join(action.option_strings)
+
+    return parser
+
+
+def save_args(args):
+    '''Save copy of args within retro workdir.'''
+
+    if torch.distributed.get_rank() == 0:
+        args_path = get_args_path(args.retro_workdir)
+        with open(args_path, "w") as f:
+            json.dump(vars(args), f, indent=4, default=lambda o : "<skipped>")
+
+    torch.distributed.barrier()
+
+
+if __name__ == "__main__":
+
+    # Initalize Megatron.
+    initialize_megatron(extra_args_provider=add_retro_args)
+
+    # Split retro tasks.
+    args = get_args()
+    args.retro_tasks = args.retro_tasks.split(",")
+
+    # Save/set retro args.
+    os.makedirs(args.retro_workdir, exist_ok=True)
+    save_args(args)
+    set_retro_args(args)
+
+    # Select task to run.
+    for task in args.retro_tasks:
+
+        print_rank_0("start '%s'." % task)
+
+        # Run all stages.
+        if task == "build":
+            build_db()
+            torch.distributed.barrier()
+            build_index()
+            torch.distributed.barrier()
+            query_pretraining_neighbors()
+
+        # DB (i.e., chunk db).
+        elif task == "db-build":
+            build_db()
+
+        # Index.
+        elif task == "index-build":
+            build_index() # calls both train + add.
+        elif task == "index-train":
+            train_index() # train only
+        elif task == "index-add":
+            add_to_index() # add only
+
+        # Pretraining.
+        elif task == "pretraining-query-neighbors":
+            query_pretraining_neighbors()
+
+        else:
+            raise Exception("specialize for task '%s'." % task)
+
+        torch.distributed.barrier()
+
+        print_rank_0("end '%s'." % task)

tools/retro/pretraining/chunk_dataset.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+import os
+import torch
+
+from megatron import get_retro_args, print_rank_0
+from megatron.data.gpt_dataset import build_train_valid_test_datasets
+from megatron.training import (
+    build_train_valid_test_data_loaders,
+    update_train_iters,
+)
+from tools.retro.db.utils import get_indexed_dataset_infos
+from tools.retro.utils import get_num_chunks_per_sample
+
+from .utils import get_pretraining_workdir
+
+
+class ChunkDataset(torch.utils.data.Dataset):
+    '''Pretraining chunk dataset wraps a standard GPT dataset.
+
+    This dataset conceptually divides each sample (e.g., length 2048)
+    into chunks (e.g., length 64) and restructures them into a list of
+    chunks (e.g., length num_samples * num_chunks_per_sample).
+    '''
+
+    def __init__(self, sample_dataset, chunk_length):
+
+        super().__init__()
+
+        self.sample_dataset = sample_dataset
+
+        self.chunk_length = chunk_length
+        self.n_chunks_per_sample = get_num_chunks_per_sample()
+        self.n_samples = len(sample_dataset)
+        self.n_chunks = self.n_samples * self.n_chunks_per_sample
+
+    def __len__(self):
+        return self.n_chunks
+
+    def __getitem__(self, idx):
+
+        # Convert global chunk index to global sample index & local chunk index.
+        sample_idx = idx // self.n_chunks_per_sample
+        chunk_idx = idx % self.n_chunks_per_sample
+
+        # Extract sample data.
+        sample = self.sample_dataset[sample_idx]
+        sample_token_ids = sample["text"]
+        sample_doc_ids = sample["doc_ids"]
+
+        # Chunk start/end token idxs.
+        token_start_idx = chunk_idx * self.chunk_length
+        token_end_idx = token_start_idx + self.chunk_length
+        chunk_token_ids = sample_token_ids[token_start_idx:token_end_idx]
+
+        # Sample.
+        return {
+            "doc_ids" : sample_doc_ids,
+            "text" : chunk_token_ids,
+        }
+
+
+def verify_indexed_dataset_order():
+    '''Verify pretraining order same as DB order.'''
+
+    args = get_retro_args()
+
+    # DB dataset prefixes.
+    db_indexed_dataset_infos = get_indexed_dataset_infos()
+    db_prefixes = [ info["prefix"] for info in db_indexed_dataset_infos ]
+
+    # Verify order & prefixes.
+    assert len(args.data_path) >= 2, "blendable dataset supported only."
+    pretraining_prefixes = args.data_path[1:None:2]
+
+    if len(db_prefixes) != len(pretraining_prefixes):
+        raise Exception("inconsistent dataset count between db & pretraining.")
+    if db_prefixes != pretraining_prefixes:
+        raise Exception("inconsistent dataset order between db & pretraining.")
+
+
+def train_valid_test_datasets_provider(train_val_test_num_samples):
+    """Build train, valid, and test datasets."""
+
+    args = get_retro_args()
+
+    print_rank_0('> building train, validation, and test datasets '
+                 'for GPT ...')
+    train_ds, valid_ds, test_ds = build_train_valid_test_datasets(
+        data_prefix=args.data_path,
+        data_impl=args.data_impl,
+        splits_string=args.split,
+        train_valid_test_num_samples=train_val_test_num_samples,
+        seq_length=args.retro_gpt_seq_length,
+        seed=args.seed,
+        skip_warmup=(not args.mmap_warmup),
+        return_doc_ids=args.retro_return_doc_ids)
+    print_rank_0("> finished creating pretrained GPT datasets ...")
+
+    return train_ds, valid_ds, test_ds
+
+
+def get_chunk_dataset_map():
+    '''Get train, valid, test chunk datasets.'''
+
+    args = get_retro_args()
+
+    # Update train iters.
+    update_train_iters(args)
+
+    args.iteration = 0
+    args.consumed_train_samples = 0
+
+    # Verify indexed dataset order.
+    verify_indexed_dataset_order()
+
+    # Datasets.
+    print_rank_0(" > data loader.")
+    train_data_loader, valid_data_loader, test_data_loader \
+        = build_train_valid_test_data_loaders(
+            train_valid_test_datasets_provider)
+
+    data_loader_map = {
+        "train" : train_data_loader,
+        "valid" : valid_data_loader,
+        "test" : test_data_loader,
+    }
+
+    # Info dict.
+    workdir = get_pretraining_workdir()
+    dataset_map = {
+        key : {
+            "neighbor_dir" : os.path.join(
+                workdir,
+                os.path.basename(loader.dataset.datasets[0].index_prefix),
+            ),
+            "data" : ChunkDataset(loader.dataset, args.retro_gpt_chunk_length),
+        }
+        for key, loader in data_loader_map.items() if loader
+    }
+
+    return dataset_map

tools/retro/pretraining/query.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+from collections import defaultdict
+import numpy as np
+import os
+import time
+import torch
+from tqdm import tqdm
+
+from megatron import get_retro_args, mpu, print_rank_0
+from tools.bert_embedding import BertEmbedder
+from tools.bert_embedding.utils import get_missing_blocks_by_rank
+from tools.retro.db.utils import (
+    get_merged_train_dataset as get_db_merged_train_dataset,
+    get_train_doc_chunk_map,
+)
+from tools.retro.external_libs import faiss, h5py
+from tools.retro.index.factory import IndexFactory
+from tools.retro.index.utils import get_index_dir, num_samples_to_block_ranges
+from tools.retro.utils import GPTToTextDataset
+
+from .chunk_dataset import get_chunk_dataset_map
+
+
+def get_index(chunk_db_dataset, ondisk=False):
+    '''Read index from disk.'''
+
+    args = get_retro_args()
+
+    # Chunk db block ranges.
+    n_db_chunks = len(chunk_db_dataset)
+    dataset_block_ranges = num_samples_to_block_ranges(n_db_chunks)
+
+    # Load index.
+    index_wrapper = IndexFactory.get_index(args.retro_index_type)
+    index_dir = get_index_dir()
+    added_index_path = index_wrapper.get_added_index_path()
+    if ondisk:
+        index = faiss.read_index(added_index_path, faiss.IO_FLAG_MMAP)
+    else:
+        index = faiss.read_index(added_index_path)
+
+    # Search parameters.
+    faiss.ParameterSpace().set_index_parameter(index, "efSearch",
+                                               args.retro_ef_search)
+    faiss.ParameterSpace().set_index_parameter(index, "nprobe",
+                                               args.retro_nprobe)
+
+    return index
+
+
+def embed_block(gpt_dataset, block, embedder):
+    '''Embed block of chunks.'''
+    text_block_dataset = torch.utils.data.Subset(
+        GPTToTextDataset(gpt_dataset),
+        range(*block["range"]),
+    )
+    return embedder.embed_text_dataset(text_block_dataset)
+
+
+def query_embeddings(index, banned_chunk_map, chunk_id_range,
+                     embeddings, sample_map, n_chunks_per_sample,
+                     verbose=True):
+    '''Query neighbors of a block of embeddings.'''
+
+    args = get_retro_args()
+
+    # Query neighbor ids.
+    if verbose: print_rank_0("search.")
+    t = time.time()
+    assert index.ntotal > 0, "check we don't accidentally have an empty index."
+    _, query_neighbor_ids = \
+        index.search(embeddings, args.retro_num_neighbors_query)
+    if verbose: print_rank_0("  time : %.3f sec." % (time.time() - t))
+
+    # Banned neighbor ids.
+    if verbose: print_rank_0("get banned neighbor ids.")
+    sample_banned_chunk_id_map = {}
+    for sample_id, sample in sample_map.items():
+        dataset_idx = sample["dataset_idx"].item()
+        doc_ids = sample["doc_ids"].tolist()
+        banned_chunk_ids = set()
+        for doc_id in doc_ids:
+            banned_chunk_ids.update(banned_chunk_map[(dataset_idx, doc_id)])
+        sample_banned_chunk_id_map[sample_id] = banned_chunk_ids
+
+    # Filter banned neighbor ids.
+    if verbose: print_rank_0("filter banned neighbor ids.")
+    filtered_neighbor_ids = np.full(
+        shape=(len(query_neighbor_ids), args.retro_num_neighbors_target),
+        fill_value=-1,
+        dtype="int64",
+    )
+    min_chunk_id, max_chunk_id = chunk_id_range
+    for chunk_id in range(min_chunk_id, max_chunk_id):
+
+        sample_id = chunk_id // n_chunks_per_sample
+
+        # Get valid neighbors (!= -1).
+        query_row = [ i for i in query_neighbor_ids[chunk_id-min_chunk_id]
+                      if i >= 0 ]
+
+        # Filter row.
+        filtered_row = [i for i in query_row
+                        if i not in sample_banned_chunk_id_map[sample_id]]
+        filtered_row = filtered_row[:args.retro_num_neighbors_target]
+        filtered_row += \
+            [-1] * (args.retro_num_neighbors_target - len(filtered_row))
+        filtered_neighbor_ids[chunk_id-min_chunk_id] = filtered_row
+
+    return query_neighbor_ids, filtered_neighbor_ids
+
+
+def query_embedding_block(index, banned_chunk_map, chunk_id_range,
+                          embeddings, sample_map, n_chunks_per_sample):
+
+    query_neighbor_ids = []
+    filtered_neighbor_ids = []
+
+    # Query in sub-blocks.
+    partial_block_size = 1000
+    for partial_start_idx in tqdm(
+            range(0, len(embeddings), partial_block_size),
+            "search",
+    ):
+        partial_end_idx = min(len(embeddings),
+                              partial_start_idx + partial_block_size)
+        partial_embeddings = embeddings[partial_start_idx:partial_end_idx]
+        partial_chunk_id_range = (
+            chunk_id_range[0] + partial_start_idx,
+            chunk_id_range[0] + partial_end_idx,
+        )
+        partial_query_neighbor_ids, partial_filtered_neighbor_ids = \
+            query_embeddings(index, banned_chunk_map, partial_chunk_id_range,
+                             partial_embeddings, sample_map, n_chunks_per_sample,
+                             verbose=False)
+        query_neighbor_ids.append(partial_query_neighbor_ids)
+        filtered_neighbor_ids.append(partial_filtered_neighbor_ids)
+
+    # Concatenate.
+    query_neighbor_ids = np.concatenate(query_neighbor_ids, axis=0)
+    filtered_neighbor_ids = np.concatenate(filtered_neighbor_ids, axis=0)
+
+    return query_neighbor_ids, filtered_neighbor_ids
+
+
+def query_block_neighbors(index, banned_chunk_map, chunk_dataset,
+                          block, embedder):
+    '''Query neighbors of a dataset block (i.e., range).'''
+
+    args = get_retro_args()
+    n_chunks_per_sample = chunk_dataset.n_chunks_per_sample
+
+    # Sample map.
+    sample_ids = sorted(list(set(chunk_id // n_chunks_per_sample
+                                 for chunk_id in range(*block["range"]))))
+    sample_map = {i:chunk_dataset.sample_dataset[i] for i in sample_ids}
+
+    # Embed block.
+    embeddings = embed_block(chunk_dataset, block, embedder)
+
+    # Query embeddings.
+    _, filtered_neighbor_ids = query_embedding_block(
+        index, banned_chunk_map, block["range"],
+        embeddings, sample_map,
+        n_chunks_per_sample)
+
+    # Save neighbors.
+    print_rank_0("save neighbors.")
+    os.makedirs(os.path.dirname(block["path"]), exist_ok=True)
+    f = h5py.File(block["path"], "w")
+    f.create_dataset("neighbors", data=filtered_neighbor_ids)
+    f.close()
+
+
+def query_dataset_neighbors(index, banned_chunk_map,
+                            prefix, chunk_dataset, neighbor_dir,
+                            embedder):
+    '''Query neighbors of each chunk within a dataset.'''
+
+    args = get_retro_args()
+
+    def validate(f):
+        assert f["neighbors"].shape[1] == args.retro_num_neighbors_target, \
+            "neighbors.shape == %s; num_neighbors_target == %d." % (
+                str(f["neighbors"].shape),
+                args.retro_num_neighbors_target,
+            )
+    n_missing_blocks, missing_neighbor_blocks = get_missing_blocks_by_rank(
+        neighbor_dir,
+        len(chunk_dataset),
+        args.retro_block_size,
+        validate=validate,
+    )
+
+    # Query each block.
+    for block_index, block in enumerate(missing_neighbor_blocks):
+
+        if block is not None:
+
+            # Progress.
+            print_rank_0("query '%s' block %d / %d ... %s." % (
+                prefix,
+                block_index,
+                len(missing_neighbor_blocks),
+                block["path"],
+            ))
+
+            # Query block neighbors.
+            query_block_neighbors(index, banned_chunk_map,
+                                  chunk_dataset, block, embedder)
+
+        # Synchronize progress across all ranks. (for easier observation)
+        print_rank_0(" > waiting for other ranks to finish block.")
+        torch.distributed.barrier()
+
+
+def query_pretraining_neighbors():
+    '''Query pretraining datasets (train & valid).'''
+
+    args = get_retro_args()
+
+    # Num threads.
+    faiss.omp_set_num_threads(64)
+
+    # Load chunk db dataset.
+    print_rank_0("load chunk db dataset.")
+    chunk_db_dataset = get_db_merged_train_dataset()
+
+    # Load index, banned chunk ids, datasets.
+    print_rank_0(" > get index.")
+    index = get_index(chunk_db_dataset)
+
+    print_rank_0(" > get banned doc-chunk id map.")
+    banned_chunk_map = get_train_doc_chunk_map()
+
+    print_rank_0(" > get dataset map.")
+    chunk_dataset_map = get_chunk_dataset_map()
+
+    # Bert embedder.
+    embedder = BertEmbedder(args.retro_bert_batch_size,
+                            args.retro_bert_max_chunk_length,
+                            args.bert_embedder_type)
+
+    # Query each (i.e., train, valid, test) dataset.
+    print_rank_0(" > query.")
+    for prefix, info in chunk_dataset_map.items():
+        print_rank_0(" > query '%s' dataset ... %d samples." %
+                     (prefix, len(info["data"])))
+        query_dataset_neighbors(index, banned_chunk_map,
+                                prefix, info["data"], info["neighbor_dir"],
+                                embedder)

tools/retro/pretraining/retro_dataset.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+import numpy as np
+import os
+import torch
+
+from megatron import get_args, get_retro_args
+from tools.bert_embedding.utils import get_index_path_map
+from tools.retro.db.utils import get_merged_train_dataset as get_db_dataset
+from tools.retro.external_libs import h5py
+
+from .chunk_dataset import get_chunk_dataset_map
+
+
+class RetroDataset(torch.utils.data.Dataset):
+    '''Dataset of retro samples.
+
+    Each sample contains the original GPT sample, along with the token IDs
+    of each neighbor of each chunk within the sequence. Neighbor array has
+    shape (num_chunks_per_sample, num_neighbors, num_retrieved_tokens).
+    '''
+
+    def __init__(self,
+                 num_neighbors,
+                 num_retrieved_chunks,
+                 block_size,
+                 db_dataset,
+                 chunk_dataset,
+                 neighbor_path_map):
+        '''Note: chunk dataset wraps original GPT dataset (see
+        chunk_dataset.py).'''
+
+        super().__init__()
+
+        self.num_neighbors = num_neighbors
+        self.num_retrieved_chunks = num_retrieved_chunks
+        self.block_size = block_size
+        self.db_dataset = db_dataset
+        self.chunk_dataset = chunk_dataset
+        self.neighbor_path_map = neighbor_path_map
+
+    def __len__(self):
+        return len(self.chunk_dataset.sample_dataset)
+
+    def __getitem__(self, sample_idx):
+
+        n_chunks_per_sample = self.chunk_dataset.n_chunks_per_sample
+
+        # Get standard sample.
+        sample = self.chunk_dataset.sample_dataset[sample_idx]
+
+        # Sample idx to chunk idxs.
+        chunk_idxs = list(range(
+            sample_idx * n_chunks_per_sample,
+            (sample_idx + 1) * n_chunks_per_sample,
+        ))
+
+        # Collect retrieved tokens.
+        all_retrieved_chunk_ids = []
+        all_retrieved_token_ids = []
+        for chunk_idx in chunk_idxs:
+
+            # Neighbor chunk ids.
+            neighbor_path = self.neighbor_path_map[chunk_idx]
+            with h5py.File(neighbor_path, "r") as f:
+                neighbor_chunk_ids = f["neighbors"] \
+                    [chunk_idx % self.block_size, :self.num_neighbors].tolist()
+
+            # Retrieved (neighbor + continuation) token ids.
+            retrieved_chunk_ids = []
+            retrieved_token_ids = []
+            for neighbor_chunk_id in neighbor_chunk_ids:
+                current_chunk_ids = [
+                    i % len(self.db_dataset)
+                    for i in range(
+                            neighbor_chunk_id,
+                            neighbor_chunk_id + self.num_retrieved_chunks)]
+                current_token_ids = [self.db_dataset[ci]["text"]
+                                     for ci in current_chunk_ids]
+                retrieved_chunk_ids.append(current_chunk_ids)
+                retrieved_token_ids.append(current_token_ids)
+
+            # Collect retrieved tokens.
+            all_retrieved_chunk_ids.append(retrieved_chunk_ids)
+            all_retrieved_token_ids.append(retrieved_token_ids)
+
+        # Reshape retrieved tokens.
+        all_retrieved_chunk_ids = np.array(all_retrieved_chunk_ids) \
+            .reshape((n_chunks_per_sample, self.num_neighbors, -1))
+        all_retrieved_token_ids = np.array(all_retrieved_token_ids) \
+            .reshape((n_chunks_per_sample, self.num_neighbors, -1))
+
+        # Sample.
+        sample = {
+            **sample,
+            "neighbor_chunks" : all_retrieved_chunk_ids,
+            "neighbor_tokens" : all_retrieved_token_ids,
+        }
+
+        return sample
+
+
+def get_retro_datasets():
+    '''Get train, valid, test retro datasets.'''
+
+    args = get_args()
+    retro_args = get_retro_args()
+
+    # DB dataset.
+    db_dataset = get_db_dataset()
+
+    # Retro datasets.
+    chunk_ds_info_map = get_chunk_dataset_map()
+    retro_dataset_map = {}
+    for data_key, chunk_ds_info in chunk_ds_info_map.items():
+
+        chunk_dataset = chunk_ds_info["data"]
+        neighbor_dir = chunk_ds_info["neighbor_dir"]
+        neighbor_path_map = get_index_path_map(neighbor_dir)
+
+        # Verify dataset prefixes.
+        sample_prefix = chunk_dataset.sample_dataset.datasets[0].index_prefix
+        neighbor_prefix = os.path.basename(neighbor_dir)
+        assert sample_prefix == neighbor_prefix, \
+            "inconsistent dataset source; '%s' vs. '%s'." % \
+            (sample_prefix, neighbor_prefix)
+
+        # Verify num chunks.
+        n_sample_chunks = len(chunk_dataset)
+        n_neighbor_chunks = len(neighbor_path_map.id_index_map)
+
+        if n_sample_chunks != n_neighbor_chunks:
+            print("neighbor_dir : %s" % neighbor_dir)
+            print("neighbor_path_map : %s" % neighbor_path_map)
+            raise Exception("num sampled chunks (%d) != num neighbor chunks (%d)"
+                            % (n_sample_chunks, n_neighbor_chunks))
+
+        # Retro dataset.
+        retro_dataset_map[data_key] = RetroDataset(
+            num_neighbors=args.retro_num_neighbors,
+            num_retrieved_chunks=args.retro_num_retrieved_chunks,
+            block_size=retro_args.retro_block_size,
+            db_dataset=db_dataset,
+            chunk_dataset=chunk_dataset,
+            neighbor_path_map=neighbor_path_map,
+        )
+
+    # Extract datasets.
+    train_ds = retro_dataset_map.get("train", None)
+    valid_ds = retro_dataset_map.get("valid", None)
+    test_ds = retro_dataset_map.get("test", None)
+
+    return train_ds, valid_ds, test_ds

tools/retro/pretraining/utils.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+import os
+
+from megatron import get_retro_args
+
+
+def get_pretraining_workdir():
+    args = get_retro_args()
+    return os.path.join(args.retro_workdir, "pretraining")

tools/retro/utils.py

+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+
+import os
+import torch
+import types
+
+from megatron import get_retro_args
+from megatron.tokenizer.tokenizer import (
+    _BertWordPieceTokenizer,
+    _GPT2BPETokenizer,
+)
+
+
+def get_args_path(workdir):
+    '''Argument copy stored within retro workdir.'''
+    return os.path.join(workdir, "args.json")
+
+
+def get_num_chunks_per_sample():
+    '''Compute seq_length // chunk_length.'''
+    args = get_retro_args()
+    sample_length = args.retro_gpt_seq_length
+    chunk_length = args.retro_gpt_chunk_length
+    assert sample_length % chunk_length == 0
+    return sample_length // chunk_length
+
+
+def get_gpt_tokenizer():
+    '''GPT (BPE) tokenizer.'''
+    args = get_retro_args()
+    return _GPT2BPETokenizer(
+        vocab_file=args.retro_gpt_vocab_file,
+        merge_file=args.retro_gpt_merge_file,
+    )
+
+
+def get_bert_tokenizer():
+    '''Bert (Wordpiece) tokenizer.'''
+    args = get_retro_args()
+    lower_case = {
+        "BertWordPieceLowerCase" : True,
+        "BertWordPieceCase" : False,
+    }[args.retro_bert_tokenizer_type]
+    return _BertWordPieceTokenizer(
+        vocab_file=args.retro_bert_vocab_file,
+        lower_case=lower_case,
+    )
+
+
+class GPTToTextDataset(torch.utils.data.Dataset):
+    '''Dataset to convert GPT tokens to text.'''
+
+    def __init__(self, gpt_dataset):
+
+        super().__init__()
+
+        self.gpt_dataset = gpt_dataset
+        self.gpt_tokenizer = get_gpt_tokenizer()
+
+    def __len__(self):
+        return len(self.gpt_dataset)
+
+    def __getitem__(self, idx):
+        gpt_token_ids = self.gpt_dataset[idx]["text"].tolist()
+        text = self.gpt_tokenizer.detokenize(gpt_token_ids)
+        return {"text": text}