fix: rewrite GRPO data pipeline for offline record-level access

- process_list_field returns List[List[int]] preserving per-response boundaries
- GRPODataset rewritten to record-level __getitem__ (no windowing/stride)
- grpo_collate_fn pads variable-length responses into [B, G, R] tensors
- JsonlStore detects nested List[List[int]] and stores List[Tensor] per record
- Store._normalize skips nested-list keys from cumsum bookkeeping
- Pipeline._flush handles nested lists without cross-record flattening
- Export grpo_collate_fn from astrai.dataset
- 6 new GRPO tests + 2 updated builder tests, 114 total pass
This commit is contained in:
2026-07-17 14:34:41 +08:00
parent c17aa0dc54
commit a1ea26d367
7 changed files with 502 additions and 75 deletions
+2
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@@ -1,6 +1,7 @@
from astrai.dataset.dataset import (
BaseDataset,
DatasetFactory,
grpo_collate_fn,
)
from astrai.dataset.sampler import ResumableDistributedSampler
from astrai.dataset.storage import (
@@ -21,6 +22,7 @@ from astrai.serialization import (
__all__ = [
"BaseDataset",
"DatasetFactory",
"grpo_collate_fn",
"Store",
"StoreFactory",
"H5Store",
+116 -16
View File
@@ -15,6 +15,49 @@ from astrai.dataset.storage import (
from astrai.factory import BaseFactory
def grpo_collate_fn(batch: List[Dict[str, Tensor]]) -> Dict[str, Tensor]:
"""Collate variable-length GRPO samples into padded 3-D tensors.
Input: list of dicts, each with:
- prompts: [P_i]
- responses: list of G tensors, each [R_ij]
- masks: list of G tensors, each [R_ij]
- rewards: [G]
Output:
- prompts: [B, P_max]
- responses: [B, G, R_max]
- masks: [B, G, R_max]
- rewards: [B, G]
"""
B = len(batch)
G = len(batch[0]["responses"])
P_max = max(b["prompts"].size(0) for b in batch)
R_max = max(r.size(0) for b in batch for r in b["responses"])
prompts = torch.zeros(B, P_max, dtype=torch.long)
responses = torch.zeros(B, G, R_max, dtype=torch.long)
masks = torch.zeros(B, G, R_max, dtype=torch.bool)
rewards = torch.zeros(B, G, dtype=torch.float32)
for i, b in enumerate(batch):
p_len = b["prompts"].size(0)
prompts[i, :p_len] = b["prompts"]
rewards[i, : b["rewards"].size(0)] = b["rewards"]
for g in range(min(G, len(b["responses"]))):
r_len = b["responses"][g].size(0)
responses[i, g, :r_len] = b["responses"][g]
if g < len(b["masks"]):
masks[i, g, :r_len] = b["masks"][g]
return {
"prompts": prompts,
"responses": responses,
"masks": masks,
"rewards": rewards,
}
class BaseDataset(Dataset, ABC):
"""Abstract base class for all dataset types.
@@ -250,28 +293,85 @@ class DPODataset(BaseDataset):
@DatasetFactory.register("grpo")
class GRPODataset(BaseDataset):
"""Dataset for Group Relative Policy Optimization training."""
"""Dataset for offline Group Relative Policy Optimization.
Unlike the window-based datasets (SEQ/SFT/DPO), GRPO data is
record-structured: each sample is one prompt with its group of
responses and scalar rewards. There is no windowing or stride —
every record is an independent training unit.
Expected storage layout (produced by JsonlStore or pre-tokenized):
- ``prompts``: List[Tensor] — one 1-D token tensor per record
- ``responses``: List[List[Tensor]] — G response tensors per record
- ``masks``: List[List[Tensor]] — G mask tensors per record
- ``rewards``: List[Tensor] — one 1-D float tensor (len G) per record
"""
def __init__(self, window_size: int = 0, stride: int = 0, **kwargs):
super().__init__(window_size=window_size, stride=stride or window_size)
self._records: List[dict] = []
@property
def required_keys(self) -> List[str]:
return ["prompts", "responses", "masks", "rewards"]
def _fetch_data(self, begin_idx: int, end_idx: int, key: str) -> Tensor:
return self.storage.fetch(begin_idx, end_idx, key)
def load(self, load_path: str, storage_type: Optional[str] = None, **kwargs):
if storage_type is None:
storage_type = detect_format(load_path)
self.storage = StoreFactory.create(storage_type, **kwargs)
self._load_path = load_path
self.storage.load(load_path, **kwargs)
self._validate_keys()
self._build_records()
def _validate_keys(self):
actual_keys = set(self.storage.keys)
missing = [k for k in self.required_keys if k not in actual_keys]
if missing:
raise KeyError(
f"GRPODataset requires keys {self.required_keys}, "
f"but storage only has {sorted(actual_keys)}. Missing: {missing}"
)
def _build_records(self):
"""Unfold segmented storage into per-record lists.
``prompts`` is a flat list of 1-D tensors (one per record).
``responses`` / ``masks`` are nested lists (G tensors per record).
``rewards`` is a flat list of 1-D tensors (len G per record).
"""
prompt_segs = self.storage._data.get("prompts", [])
response_segs = self.storage._data.get("responses", [])
mask_segs = self.storage._data.get("masks", [])
reward_segs = self.storage._data.get("rewards", [])
n_records = len(prompt_segs)
self._records = []
for i in range(n_records):
self._records.append(
{
"prompts": prompt_segs[i],
"responses": response_segs[i] if i < len(response_segs) else [],
"masks": mask_segs[i] if i < len(mask_segs) else [],
"rewards": reward_segs[i]
if i < len(reward_segs)
else torch.tensor([]),
}
)
@property
def count(self) -> int:
return len(self._records)
def __len__(self) -> int:
return len(self._records)
def __getitem__(self, index: int) -> Dict[str, Tensor]:
begin_idx, end_idx = self.get_index(index)
prompts = self._fetch_data(begin_idx, end_idx, "prompts").to(dtype=torch.long)
responses = self._fetch_data(begin_idx, end_idx, "responses").to(
dtype=torch.long
)
masks = self._fetch_data(begin_idx, end_idx, "masks").to(dtype=torch.bool)
rewards = self._fetch_data(begin_idx, end_idx, "rewards")
rec = self._records[index]
return {
"prompts": prompts,
"responses": responses,
"masks": masks,
"rewards": rewards,
"prompts": rec["prompts"].to(dtype=torch.long),
"responses": [r.to(dtype=torch.long) for r in rec["responses"]],
"masks": [m.to(dtype=torch.bool) for m in rec["masks"]],
"rewards": rec["rewards"].to(dtype=torch.float32),
}
+26 -9
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@@ -148,26 +148,37 @@ class Store(ABC):
return results[0] if len(results) == 1 else torch.cat(results, dim=0)
def _normalize(self, raw: Dict[str, List[Tensor]]):
def _normalize(self, raw: Dict[str, list]):
"""Register segments and pre-compute cumulative lengths.
Does NOT concatenate — segments are kept as-is to avoid OOM on
large datasets. Sets ``self._length`` to the minimum total
element count across all keys.
element count across all flat-tensor keys.
For GRPO multi-response keys, values may be ``List[List[Tensor]]``
(one list of G tensors per record). These are stored as-is and
excluded from the cumulative-length bookkeeping since they are
accessed record-by-record via ``_data`` rather than via ``fetch``.
"""
flat_lengths = []
for key, tensors in raw.items():
self._data[key] = tensors
if not tensors:
self._cum[key] = []
flat_lengths.append(0)
continue
# Skip nested lists (GRPO responses/masks) — record-level access
if isinstance(tensors[0], list):
self._cum[key] = []
continue
cum = []
total = 0
for t in tensors:
total += t.shape[0]
cum.append(total)
self._cum[key] = cum
self._length = (
min((cum[-1] if cum else 0) for cum in self._cum.values())
if self._cum
else 0
)
flat_lengths.append(cum[-1] if cum else 0)
self._length = min(flat_lengths) if flat_lengths else 0
class StoreFactory(BaseFactory["Store"]):
@@ -274,7 +285,13 @@ class JsonlStore(Store):
for key, ids in result.items():
if key not in raw:
raw[key] = []
raw[key].append(torch.tensor(ids, dtype=self._infer_dtype(ids)))
if ids and isinstance(ids[0], list):
# GRPO multi-response: List[List[int]] → List[Tensor]
raw[key].append(
[torch.tensor(sub, dtype=self._infer_dtype(sub)) for sub in ids]
)
else:
raw[key].append(torch.tensor(ids, dtype=self._infer_dtype(ids)))
for jsonl_path in sorted(root.glob("*.jsonl")):
with open(jsonl_path, "r", encoding="utf-8") as f:
@@ -314,7 +331,7 @@ class JsonlStore(Store):
@staticmethod
def _primary_ids(result: dict) -> List[int]:
"""Return the first integer list in *result* as the primary id sequence."""
"""Return the first flat integer list in *result* as the primary id sequence."""
for val in result.values():
if isinstance(val, list) and val and isinstance(val[0], int):
return val
+34 -21
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@@ -95,8 +95,15 @@ class SectionRenderer:
return all_ids, loss_mask
def process_list_field(self, item: dict, sections: list, config, tokenizer):
all_ids: list[int] = []
loss_mask: list[int] = []
"""Tokenize a list-valued field, preserving per-element boundaries.
Returns ``(list_of_id_lists, list_of_mask_lists)`` where each
inner list corresponds to one element of the source list. This
is critical for GRPO where each response must stay a separate
sequence so the strategy can form a ``[G, R]`` tensor.
"""
per_item_ids: list[list[int]] = []
per_item_masks: list[list[int]] = []
for sec in sections:
field = sec["field"]
@@ -108,17 +115,13 @@ class SectionRenderer:
continue
for val in values:
ids: list[int] = []
mask: list[int] = []
if use_template:
if isinstance(val, list):
wrapper = {field: val}
self._append_template(
wrapper,
field,
action,
tokenizer,
config,
all_ids,
loss_mask,
wrapper, field, action, tokenizer, config, ids, mask
)
else:
wrapper = {field: str(val)}
@@ -130,17 +133,19 @@ class SectionRenderer:
False,
False,
config,
all_ids,
loss_mask,
ids,
mask,
)
if ids:
max_len = config.preprocessing.max_seq_len
ids = ids[:max_len]
mask = mask[: len(ids)]
per_item_ids.append(ids)
per_item_masks.append(mask)
max_len = config.preprocessing.max_seq_len
all_ids = all_ids[:max_len]
loss_mask = loss_mask[: len(all_ids)]
if not all_ids:
if not per_item_ids:
return None, None
return all_ids, loss_mask
return per_item_ids, per_item_masks
@staticmethod
def is_value_section(sections: list) -> bool:
@@ -282,10 +287,18 @@ class MultiOutputMaskBuilder(BaseMaskBuilder):
ids, mask = self.renderer.process_list_field(
item, sections, config, tokenizer
)
else:
ids, mask = self.renderer.process_sections(
item, sections, config, tokenizer, is_top_level=True
)
if ids is None:
continue
# ids is List[List[int]] — preserve per-response structure
result[output_key] = ids
if mask is not None:
result[mask_key] = mask
any_output = True
continue
ids, mask = self.renderer.process_sections(
item, sections, config, tokenizer, is_top_level=True
)
if ids is None:
continue
+18 -3
View File
@@ -180,9 +180,24 @@ class Pipeline:
dt = _STR_TO_DTYPE.get(
self.config.output.dtype.get(key, "int32"), torch.int32
)
tensors[key] = [
torch.tensor(list(chain.from_iterable(ids_list)), dtype=dt)
]
# GRPO multi-response keys store List[List[int]] per record
# (responses/masks). Rewards store List[float] per record.
# Both produce List[Tensor] (one tensor per record), but
# responses need inner flattening while rewards do not.
if ids_list and isinstance(ids_list[0], list):
tensors[key] = [
torch.tensor(
list(chain.from_iterable(ids))
if ids and isinstance(ids[0], list)
else ids,
dtype=dt,
)
for ids in ids_list
]
else:
tensors[key] = [
torch.tensor(list(chain.from_iterable(ids_list)), dtype=dt)
]
if mode == "continuous" and original_sequences:
pos_ids = self._position_id.generate(keys.get("sequence", []))
+290 -23
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@@ -327,43 +327,82 @@ def test_normalize_mixed_empty_key():
def test_grpo_dataset_dtype(base_test_env):
"""GRPO dataset returns correct dtypes for per-record structured data."""
from astrai.dataset.dataset import GRPODataset
test_dir = base_test_env["test_dir"]
dummy_data = {
"prompts": [torch.randint(0, 100, (100,), dtype=torch.int32)],
"responses": [torch.randint(0, 100, (100,), dtype=torch.int32)],
"masks": [torch.ones(100, dtype=torch.int32)],
"rewards": [torch.ones(100, dtype=torch.float32)],
}
dataset = _make_seq_dataset(
test_dir, "grpo_dtype", train_type="grpo", data=dummy_data, window_size=32
)
G = 4
dataset = GRPODataset()
dataset.storage = type(
"FakeStore",
(),
{
"keys": ["prompts", "responses", "masks", "rewards"],
"_data": {
"prompts": [torch.randint(0, 100, (10,), dtype=torch.int32)],
"responses": [
[torch.randint(0, 100, (5,), dtype=torch.int32) for _ in range(G)]
],
"masks": [[torch.ones(5, dtype=torch.int32) for _ in range(G)]],
"rewards": [torch.rand(G, dtype=torch.float32)],
},
},
)()
dataset._build_records()
item = dataset[0]
assert item["prompts"].dtype == torch.long
assert item["responses"].dtype == torch.long
assert item["masks"].dtype == torch.bool
assert all(r.dtype == torch.long for r in item["responses"])
assert all(m.dtype == torch.bool for m in item["masks"])
assert item["rewards"].dtype == torch.float32
def test_grpo_dataset_load(base_test_env):
"""GRPO dataset loads record-structured data with per-response boundaries."""
from astrai.dataset.dataset import GRPODataset
test_dir = base_test_env["test_dir"]
dummy_data = {
"prompts": [_rand_seq(200)],
"responses": [_rand_seq(200)],
"masks": [torch.ones(200, dtype=torch.int64)],
"rewards": [torch.rand(200, dtype=torch.float32)],
}
dataset = _make_seq_dataset(
test_dir, "grpo_test", train_type="grpo", data=dummy_data
)
assert len(dataset) > 0
G = 3
prompt_len = 8
resp_lens = [5, 7, 4]
dataset = GRPODataset()
dataset.storage = type(
"FakeStore",
(),
{
"keys": ["prompts", "responses", "masks", "rewards"],
"_data": {
"prompts": [torch.randint(0, 100, (prompt_len,))],
"responses": [[torch.randint(0, 100, (rl,)) for rl in resp_lens]],
"masks": [[torch.ones(rl, dtype=torch.int64) for rl in resp_lens]],
"rewards": [torch.tensor([0.9, 0.3, 0.7], dtype=torch.float32)],
},
},
)()
dataset._build_records()
assert len(dataset) == 1
item = dataset[0]
assert "prompts" in item
assert "responses" in item
assert "masks" in item
assert "rewards" in item
assert item["prompts"].shape[0] == 64
assert item["responses"].shape[0] == 64
# Prompts is 1-D
assert item["prompts"].shape == (prompt_len,)
# Responses is a list of G tensors with correct lengths
assert len(item["responses"]) == G
for i, r in enumerate(item["responses"]):
assert r.shape == (resp_lens[i],)
# Masks align with responses
assert len(item["masks"]) == G
for i, m in enumerate(item["masks"]):
assert m.shape == (resp_lens[i],)
# Rewards has G elements
assert item["rewards"].shape == (G,)
def test_detect_format_bin_dir(base_test_env):
@@ -621,3 +660,231 @@ def test_jsonl_store_pipeline_config_roundtrip(base_test_env):
config = PipelineConfig.from_dict(raw)
assert config.output.position_ids_mode == "doc_reset"
assert config.preprocessing.max_seq_len == 64
# ---------------------------------------------------------------------------
# GRPO end-to-end: builder → JsonlStore → GRPODataset → collate_fn
# ---------------------------------------------------------------------------
def _write_grpo_jsonl(test_dir, tokenizer_path, records):
"""Write a GRPO JSONL dataset directory with config."""
data_dir = os.path.join(test_dir, "grpo_jsonl")
os.makedirs(data_dir, exist_ok=True)
with open(os.path.join(data_dir, "data.jsonl"), "w", encoding="utf-8") as f:
for rec in records:
f.write(json.dumps(rec, ensure_ascii=False) + "\n")
config = {
"tokenizer_path": tokenizer_path,
"version": 1,
"input": {
"sources": {
"prompts": {
"sections": [
{
"field": "prompt",
"action": "mask",
"add_special_tokens": True,
}
]
},
"responses": {
"sections": [{"field": "responses", "action": "train"}],
"list_field": True,
"mask_key": "masks",
},
"rewards": {
"sections": [{"field": "rewards", "action": "value"}],
},
}
},
"mask": {"user": "mask", "assistant": "train"},
"mask_default": "mask",
"preprocessing": {"max_seq_len": 128},
"output": {"position_ids_mode": "none"},
}
with open(
os.path.join(data_dir, "dataset_config.json"), "w", encoding="utf-8"
) as f:
json.dump(config, f, ensure_ascii=False, indent=2)
return data_dir
def test_grpo_builder_preserves_response_boundaries(base_test_env):
"""MultiOutputMaskBuilder with list_field returns List[List[int]] for responses."""
from astrai.preprocessing.builder import SectionedMaskBuilder
from tests.data.conftest import make_grpo_no_template_config
tokenizer = base_test_env["tokenizer"]
tokenizer_path = _save_test_tokenizer(base_test_env["test_dir"], tokenizer)
builder = SectionedMaskBuilder()
config = make_grpo_no_template_config()
config.preprocessing.max_seq_len = 128
item = {
"prompt": "What is 2+2?",
"responses": ["4", "four", "2+2=4"],
"rewards": [0.9, 0.1, 0.5],
}
result = builder.build(item, config, tokenizer)
assert result is not None
# prompts should be flat list of ints
assert isinstance(result["prompts"], list)
assert isinstance(result["prompts"][0], int)
# responses should be list of lists (one per response)
assert isinstance(result["responses"], list)
assert isinstance(result["responses"][0], list)
assert isinstance(result["responses"][0][0], int)
assert len(result["responses"]) == 3
# masks should match responses structure
assert isinstance(result["masks"], list)
assert len(result["masks"]) == 3
for i in range(3):
assert len(result["masks"][i]) == len(result["responses"][i])
# rewards should be flat list of floats
assert isinstance(result["rewards"], list)
assert all(isinstance(r, float) for r in result["rewards"])
assert len(result["rewards"]) == 3
def test_grpo_end_to_end_jsonl(base_test_env):
"""Full GRPO pipeline: JSONL → JsonlStore → GRPODataset → collate_fn."""
from astrai.dataset.dataset import grpo_collate_fn
test_dir = base_test_env["test_dir"]
tokenizer = base_test_env["tokenizer"]
tokenizer_path = _save_test_tokenizer(test_dir, tokenizer)
records = [
{
"prompt": "What is 2+2?",
"responses": ["4", "four", "The answer is 4"],
"rewards": [0.9, 0.1, 0.5],
},
{
"prompt": "Write a haiku",
"responses": ["Leaves fall", "Cherry blossoms bloom in spring"],
"rewards": [0.3, 0.8],
},
]
data_dir = _write_grpo_jsonl(test_dir, tokenizer_path, records)
dataset = DatasetFactory.load("grpo", data_dir, window_size=0)
assert len(dataset) == 2
# Item 0: 3 responses
item0 = dataset[0]
assert item0["prompts"].ndim == 1
assert len(item0["responses"]) == 3
assert len(item0["masks"]) == 3
assert item0["rewards"].shape == (3,)
for r, m in zip(item0["responses"], item0["masks"]):
assert r.shape == m.shape
# Item 1: 2 responses (different group size)
item1 = dataset[1]
assert len(item1["responses"]) == 2
assert item1["rewards"].shape == (2,)
# Collate: batch records with same G (item0 has G=3)
batch = grpo_collate_fn([item0, item0])
assert batch["prompts"].shape[0] == 2
assert batch["responses"].ndim == 3
assert batch["responses"].shape[0] == 2
assert batch["responses"].shape[1] == 3 # G=3
assert batch["masks"].shape == batch["responses"].shape
assert batch["rewards"].shape == (2, 3)
def test_grpo_collate_variable_lengths():
"""collate_fn pads variable-length responses to [B, G, R_max]."""
from astrai.dataset.dataset import grpo_collate_fn
batch = [
{
"prompts": torch.tensor([1, 2, 3]),
"responses": [torch.tensor([4, 5]), torch.tensor([6, 7, 8, 9])],
"masks": [torch.tensor([1, 1]), torch.tensor([1, 1, 1, 1])],
"rewards": torch.tensor([0.9, 0.1]),
},
{
"prompts": torch.tensor([10, 11]),
"responses": [torch.tensor([12]), torch.tensor([13, 14, 15])],
"masks": [torch.tensor([1]), torch.tensor([1, 1, 1])],
"rewards": torch.tensor([0.5, 0.5]),
},
]
result = grpo_collate_fn(batch)
assert result["prompts"].shape == (2, 3) # B=2, P_max=3
assert result["responses"].shape == (2, 2, 4) # B=2, G=2, R_max=4
assert result["masks"].shape == (2, 2, 4)
assert result["rewards"].shape == (2, 2)
# Check padding: item 1 prompt is length 2, padded to 3
assert result["prompts"][1, 2] == 0
# Check response content: item 0, response 0 is [4,5] padded to 4
assert result["responses"][0, 0, 0] == 4
assert result["responses"][0, 0, 1] == 5
assert result["responses"][0, 0, 2] == 0 # padded
assert result["masks"][0, 0, 2] == False # padded
# Check response content: item 0, response 1 is [6,7,8,9] no padding
assert result["responses"][0, 1, 3] == 9
assert result["masks"][0, 1, 3] == True
def test_grpo_multiple_records(base_test_env):
"""GRPODataset loads multiple records with correct structure."""
from astrai.dataset.dataset import GRPODataset
G = 4
n_records = 5
dummy_responses = [
[torch.randint(0, 100, (np.random.randint(3, 8),)) for _ in range(G)]
for _ in range(n_records)
]
dataset = GRPODataset()
dataset.storage = type(
"FakeStore",
(),
{
"keys": ["prompts", "responses", "masks", "rewards"],
"_data": {
"prompts": [torch.randint(0, 100, (10,)) for _ in range(n_records)],
"responses": dummy_responses,
"masks": [
[torch.ones(r.shape[0], dtype=torch.int64) for r in resps]
for resps in dummy_responses
],
"rewards": [
torch.rand(G, dtype=torch.float32) for _ in range(n_records)
],
},
},
)()
dataset._build_records()
assert len(dataset) == n_records
for i in range(n_records):
item = dataset[i]
assert len(item["responses"]) == G
assert len(item["masks"]) == G
assert item["rewards"].shape == (G,)
for g in range(G):
assert item["responses"][g].shape == item["masks"][g].shape
+16 -3
View File
@@ -349,7 +349,17 @@ def test_grpo_basic(chat_tokenizer, builder):
assert "responses" in result
assert "masks" in result
assert "rewards" in result
assert len(result["responses"]) == len(result["masks"])
# responses is List[List[int]] — one per response
assert len(result["responses"]) == 4
assert all(isinstance(r, list) for r in result["responses"])
assert all(isinstance(r[0], int) for r in result["responses"])
# masks is List[List[int]] — one per response, matching length
assert len(result["masks"]) == 4
for i in range(4):
assert len(result["masks"][i]) == len(result["responses"][i])
assert result["rewards"] == [1.0, 0.5, 0.8, 0.2]
@@ -362,8 +372,11 @@ def test_grpo_response_tokens_all_trained(chat_tokenizer, builder):
}
result = builder.build(item, config, chat_tokenizer)
masks = result["masks"]
assert all(m == 1 for m in masks)
assert len(masks) == len(result["responses"])
# masks is List[List[int]] — each response's mask should be all 1s
assert len(masks) == 2
for m in masks:
assert all(v == 1 for v in m)
assert len(m) == len(result["responses"][masks.index(m)])
def test_grpo_single_reward(chat_tokenizer, builder):