docs : 更新架构文档与 storage 注释，同步 Store 重构

- architecture.md: 类图/关系线全部更新 (BaseStorage→Store, StorageFactory→StoreFactory, 新增 MmapStore)
- architecture.md: 移除 BaseSegmentFetcher/MultiSegmentFetcher 类图与关系
- dataflow.md: 管线加入 .bin 格式, Store._data + _cum 架构
- storage.py: module docstring 改用缩进式注释风格

assets/docs/architecture.md

@@ -22,7 +22,8 @@ classDiagram
             +int n_layers
             +float norm_eps
             +int dim_ffn
-            +bool tie_weight
+            +Optional[bool] tie_weight
+            +Optional[dict] rope_scaling
             +int max_len
             +float rope_theta
             +str attn_type
@@ -52,6 +53,7 @@ classDiagram
             +int n_kv_heads
             +bool use_qk_norm
             +bool use_gated_attention
+            +Optional[dict] rope_scaling
             +Optional[str] pooling_type
             +Optional[bool] normalize_embeddings
         }
@@ -80,6 +82,7 @@ classDiagram
             +str log_dir
             +int log_interval
             +List[str] metrics
+            +Optional[LoRAConfig] lora
             +int random_seed
             +int num_workers
             +Optional[int] prefetch_factor
@@ -104,7 +107,7 @@ classDiagram
         class BaseDataset {
             +int window_size
             +int stride
-            +Optional[BaseStorage] storage
+            +Optional[Store] storage
             +load(load_path, storage_type, tokenizer)
             +__getitem__(index)
             +__len__()
@@ -126,38 +129,29 @@ classDiagram
             +__getitem__(index) Dict
         }
 
-        class BaseSegmentFetcher {
-            +List[Tensor] segments
-            +List[int] cum_lengths
-            +int total_length
-            +fetch_data(begin_idx, end_idx) Tensor
-        }
-
-        class BaseStorage {
-            +MultiSegmentFetcher _fetcher
+        class Store {
+            +Dict[str, List[Tensor]] _data
+            +Dict[str, List[int]] _cum
+            +int _length
             +keys (property)
-            +load(load_path, tokenizer)
+            +load(path, tokenizer)
             +fetch(begin, end, keys)
             +__len__()
+            -_fetch_key(key, begin, end) Tensor
+            -_normalize(raw)
         }
 
-        class H5Storage {
-            +load(load_path, tokenizer)
-            +fetch(begin, end, keys) Dict
-            +keys() List
+        class H5Store {
+            +load(path, tokenizer)
         }
 
-        class JSONStorage {
-            +load(load_path, tokenizer)
-            +fetch(begin, end, keys) Dict
-            +keys() List
+        class JSONStore {
+            +load(path, tokenizer)
         }
 
-        class MultiSegmentFetcher {
-            +Dict multi_fetchers
-            +List multi_keys
-            +key_fetch(begin_idx, end_idx, keys) Dict
-            +fetch_data(begin_idx, end_idx) Dict
+        class MmapStore {
+            +List _mmap_refs
+            +load(path, tokenizer)
         }
 
         class ResumableDistributedSampler {
@@ -165,10 +159,10 @@ classDiagram
             +int iter
         }
 
-        class StorageFactory {
+        class StoreFactory {
             +Registry _registry
             +register(name) decorator
-            +create(storage_type) BaseStorage
+            +create(storage_type) Store
         }
 
         class DatasetFactory {
@@ -457,16 +451,15 @@ classDiagram
             +on_train_end(context)
             +on_epoch_begin(context)
             +on_epoch_end(context)
-            +on_step_begin(context)
-            +on_step_end(context)
             +on_batch_begin(context)
             +on_batch_end(context)
+            +on_optimizer_step(context)
             +on_error(context)
         }
 
         class GradientClippingCallback {
             +float max_grad_norm
-            +on_step_begin(context)
+            +on_optimizer_step(context)
         }
 
         class GradientCheckpointingCallback {
@@ -512,7 +505,7 @@ classDiagram
 
         class ValidationCallback {
             +_run_validation(context)
-            +on_step_end(context)
+            +on_optimizer_step(context)
         }
 
         class CallbackFactory {
@@ -747,56 +740,58 @@ classDiagram
             +str model
             +List[AnthropicMessage] messages
             +Optional[str] system
-            +float temperature
-            +float top_p
-            +int top_k
+            +Optional[float] temperature
+            +Optional[float] top_p
+            +Optional[int] top_k
             +int max_tokens
-            +bool stream
+            +Optional[bool] stream
             +Optional[List[str]] stop_sequences
         }
 
-        class ProtocolHandler {
+        class ResponseBuilder {
             <<abstract>>
+            +prepare(request, engine) Tuple[str, GenContext, List[str]]
+            +format_stream_start(ctx) List[str]
+            +format_chunk(token) str
+            +format_stream_end(ctx, stop) List[str]
+            +format_response(ctx, content, stop) Dict
+        }
+
+        class OpenAIResponseBuilder {
+            +prepare(request, engine) Tuple
+            +format_stream_start(ctx) List[str]
+            +format_chunk(token) str
+            +format_stream_end(ctx, stop) List[str]
+            +format_response(ctx, content, stop) Dict
+        }
+
+        class AnthropicResponseBuilder {
+            +prepare(request, engine) Tuple
+            +format_stream_start(ctx) List[str]
+            +format_chunk(token) str
+            +format_stream_end(ctx, stop) List[str]
+            +format_response(ctx, content, stop) Dict
+        }
+
+        class ProtocolHandler {
             +request
             +engine
-            +build_prompt() str
-            +create_response_id() str
-            +get_stop_sequences() List[str]
-            +create_stop_checker() StopChecker
-            +on_token(ctx, token, stop_checker) Optional[str]
-            +format_stream_start(ctx) List[str]
-            +format_stream_token(ctx, token) str
-            +format_stream_end(ctx) List[str]
-            +format_non_stream_response(ctx, content) Dict
+            +builder: ResponseBuilder
             +handle() Union[StreamingResponse, Dict]
-        }
-
-        class OpenAIHandler {
-            +build_prompt() str
-            +create_response_id() str
-        }
-
-        class AnthropicHandler {
-            +build_prompt() str
-            +create_response_id() str
-            +on_token(ctx, token, stop_checker) Optional[str]
+            -_handle_stream(agen, ctx, stops) StreamingResponse
+            -_handle_non_stream(agen, ctx, stops) Dict
         }
 
         class StopChecker {
-            +has_sequences (property) bool
             +check(text) Optional[str]
-            +trim(text, matched) str
         }
 
-        class StreamContext {
+        class GenContext {
             +str resp_id
             +int created
             +str model
             +int prompt_tokens
             +int completion_tokens
-            +str accumulated
-            +Optional[str] stop_matched
-            +str last_yield_trimmed
         }
 
         class app {
@@ -876,6 +871,11 @@ classDiagram
             +unwrap_model(model) nn.Module
         }
 
+        class FSDPExecutor {
+            +_prepare_model(model) nn.Module
+            +unwrap_model(model) nn.Module
+        }
+
         class ExecutorFactory {
             +Registry _registry
             +register(name) decorator
@@ -911,12 +911,14 @@ classDiagram
     TrainCallback <|-- CheckpointCallback
     TrainCallback <|-- ProgressBarCallback
     TrainCallback <|-- MetricLoggerCallback
+    TrainCallback <|-- ValidationCallback
     BaseDataset <|-- SEQDataset
     BaseDataset <|-- SFTDataset
     BaseDataset <|-- DPODataset
     BaseDataset <|-- GRPODataset
-    BaseStorage <|-- H5Storage
-    BaseStorage <|-- JSONStorage
+    Store <|-- H5Store
+    Store <|-- JSONStore
+    Store <|-- MmapStore
     BaseSamplingStrategy <|-- TemperatureStrategy
     BaseSamplingStrategy <|-- TopKStrategy
     BaseSamplingStrategy <|-- TopPStrategy
@@ -936,20 +938,19 @@ classDiagram
     BaseFactory <|-- StrategyFactory
     BaseFactory <|-- SchedulerFactory
     BaseFactory <|-- CallbackFactory
-    BaseFactory <|-- StorageFactory
+    BaseFactory <|-- StoreFactory
     BaseFactory <|-- ExecutorFactory
     BaseFactory <|-- ConfigFactory
     BaseExecutor <|-- NoneExecutor
     BaseExecutor <|-- DDPExecutor
-    ProtocolHandler <|-- OpenAIHandler
-    ProtocolHandler <|-- AnthropicHandler
+    BaseExecutor <|-- FSDPExecutor
+    ResponseBuilder <|-- OpenAIResponseBuilder
+    ResponseBuilder <|-- AnthropicResponseBuilder
 
     %% --- Composition (strong ownership, part destroyed with whole) ---
     KVCache *-- PagePool
     KVCache *-- Storage
     KVCache *-- TaskTable
-    PagePool *-- Allocator
-    PagePool *-- PrefixCache
     InferenceEngine *-- InferenceScheduler
     InferenceScheduler *-- KVCache
     InferenceScheduler *-- Executor
@@ -963,7 +964,6 @@ classDiagram
     DecoderBlock *-- RMSNorm
     ChatCompletionRequest *-- ChatMessage
     MessagesRequest *-- AnthropicMessage
-    AutoTokenizer *-- ChatTemplate
     BaseFactory *-- Registry
     BaseExecutor *-- GradientState
     AccumOptimizer o-- GradientState
@@ -971,6 +971,9 @@ classDiagram
 
     %% --- Aggregation (weak ownership) ---
     AutoModel o-- BaseModelConfig
+    AutoTokenizer o-- ChatTemplate
+    PagePool o-- Allocator
+    PagePool o-- PrefixCache
     Trainer o-- TrainCallback
     TrainContext o-- BaseStrategy
     TrainContext o-- BaseScheduler
@@ -978,7 +981,7 @@ classDiagram
     TrainContext o-- BaseExecutor
     KvcacheView o-- Storage
     SamplingPipeline o-- BaseSamplingStrategy
-    BaseDataset o-- BaseStorage
+    BaseDataset o-- Store
 
     %% --- Dependency (uses temporarily) ---
     TrainConfig ..> BaseStrategy : selects
@@ -992,12 +995,14 @@ classDiagram
     FFNFactory ..> DeepSeekMoE : creates
     DecoderBlock ..> AttnFactory : uses
     DecoderBlock ..> FFNFactory : uses
-    StorageFactory ..> H5Storage : creates
-    StorageFactory ..> JSONStorage : creates
+    StoreFactory ..> H5Store : creates
+    StoreFactory ..> JSONStore : creates
+    StoreFactory ..> MmapStore : creates
     ConfigFactory ..> AutoRegressiveLMConfig : creates
     ConfigFactory ..> EncoderConfig : creates
     ExecutorFactory ..> NoneExecutor : creates
     ExecutorFactory ..> DDPExecutor : creates
+    ExecutorFactory ..> FSDPExecutor : creates
     TrainContextBuilder ..> ExecutorFactory : creates
     Trainer ..> TrainContextBuilder : uses
     TrainContextBuilder ..> TrainContext : creates
@@ -1009,10 +1014,10 @@ classDiagram
     KVCache ..> KvcacheView : binds
     InferenceEngine ..> GenerationRequest : uses
     InferenceEngine ..> GenerateResult : creates
-    OpenAIHandler ..> ChatCompletionRequest : receives
-    AnthropicHandler ..> MessagesRequest : receives
+    OpenAIResponseBuilder ..> ChatCompletionRequest : receives
+    AnthropicResponseBuilder ..> MessagesRequest : receives
     ProtocolHandler ..> StopChecker : creates
-    ProtocolHandler ..> StreamContext : creates
+    ProtocolHandler ..> GenContext : creates
 
     %% --- Association (general usage) ---
     Trainer --> TrainConfig
@@ -1025,8 +1030,6 @@ classDiagram
     Executor --> AutoModel
     Executor --> AutoTokenizer
     TaskManager --> AutoTokenizer
-    MultiSegmentFetcher --> BaseSegmentFetcher
-    ResumableDistributedSampler --> BaseDataset
 
 ```
 
@@ -1036,13 +1039,13 @@ classDiagram
 | Module | Components | Description |
 |--------|------------|-------------|
 | **astrai.config** | BaseConfig, BaseModelConfig, AutoRegressiveLMConfig, EncoderConfig, ConfigFactory, TrainConfig | Configuration management (to_dict/from_dict, to_file/from_file) |
-| **astrai.dataset** | BaseDataset–GRPODataset, BaseStorage–JSONStorage, StorageFactory, BaseSegmentFetcher, MultiSegmentFetcher, ResumableDistributedSampler, DatasetFactory | Dataset loading and management |
+| **astrai.dataset** | BaseDataset–GRPODataset, Store–MmapStore, StoreFactory, ResumableDistributedSampler, DatasetFactory | Dataset loading and management |
 | **astrai.serialization** | Checkpoint | Model serialization |
 | **astrai.model** | AutoModel, AutoRegressiveLM, EmbeddingEncoder, DecoderBlock, GQA, MLA, MLP, DeepSeekMoE, AttnFactory, FFNFactory, RMSNorm, Linear, RotaryEmbedding, Embedding | Neural network model |
 | **astrai.tokenize** | AutoTokenizer, ChatTemplate | Tokenizer and chat template |
 | **astrai.trainer** | Trainer, TrainContext, TrainContextBuilder, BaseStrategy–GRPOStrategy, StrategyFactory, BaseScheduler–SGDRScheduler, SchedulerFactory, TrainCallback(Protocol)–ValidationCallback, CallbackFactory, Muon | Training workflow |
-| **astrai.inference** | InferenceEngine, InferenceScheduler, Executor, KVCache–KvcacheView, Allocator–Storage, Task, TaskManager, TaskStatus, GenerationRequest, GenerateResult, BaseSamplingStrategy–SamplingPipeline, ProtocolHandler–AnthropicHandler, StopChecker, StreamContext, ChatMessage–MessagesRequest, app | Inference service |
-| **astrai.parallel** | spawn_parallel_fn, setup_parallel, get_rank/get_world_size/get_current_device, only_on_rank, BaseExecutor, ExecutorFactory, NoneExecutor, DDPExecutor, GradientState, AccumOptimizer, AccumScheduler, ParallelModel, RowParallelLinear, ColumnParallelLinear | Distributed parallel & gradient accumulation |
+| **astrai.inference** | InferenceEngine, InferenceScheduler, Executor, KVCache–KvcacheView, Allocator–Storage, Task, TaskManager, TaskStatus, GenerationRequest, GenerateResult, BaseSamplingStrategy–SamplingPipeline, ProtocolHandler, ResponseBuilder, OpenAIResponseBuilder, AnthropicResponseBuilder, StopChecker, GenContext, ChatMessage–MessagesRequest, app | Inference service |
+| **astrai.parallel** | spawn_parallel_fn, setup_parallel, get_rank/get_world_size/get_current_device, only_on_rank, BaseExecutor, ExecutorFactory, NoneExecutor, DDPExecutor, FSDPExecutor, GradientState, AccumOptimizer, AccumScheduler, ParallelModel, RowParallelLinear, ColumnParallelLinear | Distributed parallel & gradient accumulation |
 | **astrai.factory** | Registry, BaseFactory[T] | Component registration |
 | **astrai.protocols** | OptimizerProtocol, SchedulerProtocol | Structural subtyping for optimizer/scheduler wrappers |
 
@@ -1050,17 +1053,17 @@ classDiagram
 
 | Pattern | Classes | Purpose |
 |---------|---------|---------|
-| **Factory** | `AttnFactory`, `FFNFactory`, `StrategyFactory`, `DatasetFactory`, `SchedulerFactory`, `CallbackFactory`, `StorageFactory`, `ConfigFactory`, `ExecutorFactory` | Decorator-based component creation |
+| **Factory** | `AttnFactory`, `FFNFactory`, `StrategyFactory`, `DatasetFactory`, `SchedulerFactory`, `CallbackFactory`, `StoreFactory`, `ConfigFactory`, `ExecutorFactory` | Decorator-based component creation |
 | **Registry** | `BaseFactory`, `Registry` | Component registration with category/priority |
 | **Strategy** | `SEQStrategy`, `SFTStrategy`, `DPOStrategy`, `GRPOStrategy` | Training strategy switching |
 | **Strategy (Sampling)** | `TemperatureStrategy`, `TopKStrategy`, `TopPStrategy`, `SamplingPipeline` | Composable logit transformations |
-| **Template Method** | `ProtocolHandler`, `OpenAIHandler`, `AnthropicHandler` | HTTP API handler with format hooks |
+| **Strategy (API)** | `ResponseBuilder`, `OpenAIResponseBuilder`, `AnthropicResponseBuilder` | HTTP API handler with format hooks |
 | **Builder** | `TrainContextBuilder` | Chain-building training context |
 | **Observer** | `TrainCallback`, callback implementations | Training process monitoring |
 | **Context** | `TrainContext` | Unified training state bag |
 | **Object Pool** | `Allocator`, `PagePool` | Page-based KV cache with LRU eviction |
 | **Executor** | `BaseExecutor`, `NoneExecutor`, `DDPExecutor` | Gradient accumulation & model distribution |
-| **Storage** | `BaseStorage`, `H5Storage`, `JSONStorage` | Format-agnostic data access |
+| **Storage** | `Store`, `H5Store`, `JSONStore`, `MmapStore` | Format-agnostic data access with multi-segment support |
 | **Producer-Consumer** | `InferenceScheduler`, `Task`, queues | Continuous batching |
 | **AutoModel Registry** | `AutoModel`, `AutoRegressiveLM`, `EmbeddingEncoder` | Model-type dynamic loading |
 
@@ -1069,10 +1072,10 @@ classDiagram
 1. **Config → Training**: `TrainConfig` holds model, dataset, optimizer_fn, scheduler_fn, `parallel_mode`, `executor_kwargs`
 2. **Training Flow**: `Trainer` → `TrainContextBuilder` → `TrainContext`, uses `BaseStrategy` for loss, `BaseExecutor` for gradient accumulation + model distribution
 3. **Strategy Selection**: `StrategyFactory` creates strategy by `train_type`
-4. **Executor Selection**: `ExecutorFactory.create(parallel_mode, **executor_kwargs)` → `NoneExecutor` (single) / `DDPExecutor` (distributed)
+4. **Executor Selection**: `ExecutorFactory.create(cfg.parallel_mode, grad_accum_steps=cfg.grad_accum_steps, **cfg.executor_kwargs)` → `NoneExecutor` / `DDPExecutor` / `FSDPExecutor`
 5. **Inference Flow**: `InferenceEngine` → `InferenceScheduler` → `AutoRegressiveLM`, backed by `KVCache` + `SamplingPipeline`
 6. **Distributed**: `spawn_parallel_fn` + `setup_parallel` for multi-process DDP
-7. **Dataset Loading**: `DatasetFactory` creates datasets, `BaseStorage` (H5Storage/JSONStorage) loads via `BaseSegmentFetcher` + `MultiSegmentFetcher`
+7. **Dataset Loading**: `DatasetFactory` creates datasets, `Store` (H5Store/JSONStore/MmapStore) loads data with explicit `_length` and multi-segment `_data`
 8. **Checkpoint**: `Checkpoint` saves/loads safetensors + metadata (rank-0 only), extra state saved as `{key}.pt`
 9. **Scheduler**: `SchedulerFactory` creates `CosineScheduler`/`SGDRScheduler`
 10. **AutoModel**: `from_pretrained()` loads `config.json` + `model.safetensors`, `_disable_random_init` replaces `nn.init.*` with no-ops

assets/docs/dataflow.md

@@ -5,21 +5,22 @@ This document describes the data pipeline: from raw text to model input tensors.
 ## Overview
 
 ```
-Raw Text → AutoTokenizer → Token IDs → .h5/.json → Dataset → Sampler → DataLoader → Training/Inference
+Raw Text → AutoTokenizer → Token IDs → .h5/.json/.bin → Dataset → Sampler → DataLoader → Training/Inference
 ```
 
 ## Data Preparation
 
-Raw text is tokenized via `AutoTokenizer.encode()` and saved as HDF5 (`.h5`) or JSON (`.json`/`.jsonl`) files with keyed tensor groups.
+Raw text is tokenized via `AutoTokenizer.encode()` and saved as HDF5 (`.h5`), JSON (`.json`/`.jsonl`), or binary (`.bin` + `meta.json`) files with keyed tensor groups.
 
 Storage format is auto-detected by `detect_format()`; backends are dispatched via registry:
 
 ```
-StorageFactory.create("h5")   → H5Storage
-StorageFactory.create("json") → JSONStorage
+StoreFactory.create("h5")   → H5Store
+StoreFactory.create("json") → JSONStore
+StoreFactory.create("bin")  → MmapStore
 ```
 
-Both support shared memory via `.share_memory_()`.
+H5 and JSON backends support shared memory via `.share_memory_()`. Bin (mmap) uses OS page-cache sharing natively.
 
 ## Data Keys by Training Type
 
@@ -33,14 +34,14 @@ Both support shared memory via `.share_memory_()`.
 ## Dataset Architecture
 
 ```
-DatasetFactory.load(train_type, path, window_size, stride)
-  → StorageFactory.create(detect_format(path))
-    → MultiSegmentFetcher(BaseSegmentFetcher per key)
+DatasetFactory.load(train_type, path, window_size, stride, storage_type, tokenizer)
+  → StoreFactory.create(detect_format(path))
+    → Store._data[Dict[str, List[Tensor]]] + _cum[Dict[str, List[int]]]
       → BaseDataset.__getitem__(idx)
         → sliding window [begin, end) via get_index(idx)
 ```
 
-`window_size` = max input length, `stride` = step between consecutive samples.
+`window_size` = max input length, `stride` = step between consecutive samples (defaults to `window_size`).
 
 ## Sampler
 

assets/docs/inference.md

@@ -46,20 +46,22 @@ BaseSamplingStrategy → TemperatureStrategy → TopKStrategy → TopPStrategy
 `SamplingPipeline` composes them: Temperature → Top-K → Top-P → softmax → multinomial.  
 `sample()` is a convenience shortcut for one-shot usage.
 
-## Protocol Handlers (Template Method)
+## Protocol Handlers (Strategy Pattern)
 
 ```python
-class ProtocolHandler(ABC):
-    def handle(self):
-        ctx = StreamContext(...)
+class ProtocolHandler:  # concrete orchestrator
+    def handle(self, request):
+        prompt, ctx, stops = builder.prepare(request, engine)
         agen = engine.generate_async(prompt, ...)
-        if stream: self._handle_stream(agen, ctx)
-        else:      self._handle_non_stream(agen, ctx)
+        if stream: self._handle_stream(agen, ctx, stops)
+        else:      self._handle_non_stream(agen, ctx, stops)
 ```
 
-Subclass hooks: `build_prompt()`, `create_response_id()`, `format_stream_start/token/end()`, `format_non_stream_response()`.
+`ResponseBuilder` (ABC): `prepare()`, `format_stream_start()`, `format_chunk()`, `format_stream_end()`, `format_response()`.
 
-`OpenAIHandler` → `/v1/chat/completions`, `AnthropicHandler` → `/v1/messages`.
+`OpenAIResponseBuilder` → `/v1/chat/completions`, `AnthropicResponseBuilder` → `/v1/messages`.
+
+Adding a protocol = one builder file, no handler subclassing needed.
 
 ## Engine & GenerateResult
 
@@ -116,7 +118,7 @@ Supports `stop_sequences` and streaming via `event: content_block_delta`.
 | Param | Type | Default | Description |
 |-------|------|---------|-------------|
 | `messages` | List[dict] | required | Chat messages (role, content) |
-| `temperature` | float | 1.0 | Sampling temperature (0.0–2.0) |
+| `temperature` | float | 1.0 | Sampling temperature (>= 0.0) |
 | `top_p` | float | 1.0 | Nucleus threshold |
 | `top_k` | int | 50 | Top-k count |
 | `max_tokens` | int | None | Max generation length |

assets/docs/params.md

@@ -53,7 +53,7 @@
 | Parameter | Description | Default |
 |-----------|-------------|---------|
 | `--nprocs` | Number of GPUs / processes | 1 |
-| `--parallel_mode` | Parallel strategy (`none` or `ddp`) | none |
+| `--parallel_mode` | Parallel strategy (`none`, `ddp`, or `fsdp`) | none |
 | `--device_type` | Device type | cuda |
 | `--start_method` | Multiprocessing start method (`spawn`, `fork`, `forkserver`) | spawn |
 

assets/docs/training.md

@@ -82,8 +82,7 @@ on_train_begin
         on_optimizer_step
         optimizer.step()
         optimizer.zero_grad()
-
-      scheduler.step()  # called every iteration
+        scheduler.step()
     on_epoch_end
 on_train_end
 ```
@@ -190,7 +189,7 @@ context = (
 ```
 
 - Loads checkpoint weights if provided
-- Creates executor via `ExecutorFactory.create(parallel_mode, **executor_kwargs)`
+- Creates executor via `ExecutorFactory.create(cfg.parallel_mode, grad_accum_steps=cfg.grad_accum_steps, **cfg.executor_kwargs)`
 - Calls `executor.prepare(model, optimizer, dataloader, scheduler)` for model distribution (e.g. DDP) + gradient accumulation wrappers
 - Creates `ResumableDistributedSampler` for shuffle+resume
 - Builds strategy via `StrategyFactory.create(train_type, ...)`

astrai/config/train_config.py

@@ -17,8 +17,8 @@ def required(**kw):
 @dataclass
 class TrainConfig(BaseConfig):
     # basic setting
-    model: nn.Module = field(
-        default=None, metadata=required(help="Model for training.")
+    model_fn: Callable[[], nn.Module] = field(
+        default=None, metadata=required(help="Model factory for training.")
     )
     strategy: str = field(default=None, metadata=required(help="Training strategy."))
     dataset: Dataset = field(

astrai/dataset/__init__.py

@@ -4,15 +4,17 @@ from astrai.dataset.dataset import (
 )
 from astrai.dataset.sampler import ResumableDistributedSampler
 from astrai.dataset.storage import (
-    BaseSegmentFetcher,
-    BaseStorage,
-    H5Storage,
-    JSONStorage,
-    MultiSegmentFetcher,
-    StorageFactory,
+    H5Store,
+    JSONStore,
+    MmapStore,
+    Store,
+    StoreFactory,
     detect_format,
+    json_to_bin,
+    load_bin,
     load_h5,
     load_json,
+    save_bin,
     save_h5,
     save_json,
 )
@@ -20,16 +22,18 @@ from astrai.dataset.storage import (
 __all__ = [
     "BaseDataset",
     "DatasetFactory",
-    "BaseSegmentFetcher",
-    "MultiSegmentFetcher",
-    "BaseStorage",
-    "H5Storage",
-    "JSONStorage",
-    "StorageFactory",
+    "Store",
+    "StoreFactory",
+    "H5Store",
+    "JSONStore",
+    "MmapStore",
     "detect_format",
     "save_h5",
     "load_h5",
     "save_json",
     "load_json",
+    "save_bin",
+    "load_bin",
+    "json_to_bin",
     "ResumableDistributedSampler",
 ]

astrai/dataset/dataset.py

@@ -8,8 +8,8 @@ from torch import Tensor
 from torch.utils.data import Dataset
 
 from astrai.dataset.storage import (
-    BaseStorage,
-    StorageFactory,
+    Store,
+    StoreFactory,
     detect_format,
 )
 from astrai.factory import BaseFactory
@@ -26,7 +26,7 @@ class BaseDataset(Dataset, ABC):
         super().__init__()
         self.window_size = window_size
         self.stride = stride
-        self.storage: Optional[BaseStorage] = None
+        self.storage: Optional[Store] = None
 
     @property
     def required_keys(self) -> List[str]:
@@ -65,7 +65,7 @@ class BaseDataset(Dataset, ABC):
         """
         if storage_type is None:
             storage_type = detect_format(load_path)
-        self.storage = StorageFactory.create(storage_type)
+        self.storage = StoreFactory.create(storage_type)
         self._load_path = load_path
         self.storage.load(load_path, tokenizer=tokenizer)
         self._validate_keys()
@@ -148,7 +148,7 @@ class DatasetFactory(BaseFactory["BaseDataset"]):
     """
 
     @classmethod
-    def _validate_component(cls, dataset_cls: type) -> None:
+    def _validate_component(cls, dataset_cls: type):
         """Validate that the dataset class inherits from BaseDataset."""
         if not issubclass(dataset_cls, BaseDataset):
             raise TypeError(f"{dataset_cls.__name__} must inherit from BaseDataset")

astrai/dataset/storage.py

@@ -1,7 +1,20 @@
 """Storage backends for different data formats.
 
-Each storage handles format-specific loading (HDF5, JSON, etc.) and provides
-a uniform interface for data access and length observation via fetchers.
+Layers:
+  - I/O layer:       save_* / load_* functions, read/write raw files (HDF5/JSON/bin)
+                     return Dict[str, List[Tensor]] — format-specific, no state
+  - Store (ABC):     central abstraction, normalizes multi-segment into
+                     Dict[str, List[Tensor]] per key via _normalize(),
+                     fetch() uses bisect across segments — no forced concat
+  - Dataset layer:   BaseDataset owns a Store, only calls store.fetch(begin, end, key)
+
+Key properties:
+  - Multi-segment:   segments kept as-is, no forced concatenation — safe for
+                     datasets larger than RAM
+  - Explicit length: _length = min(total elements across keys), set at load,
+                     __len__ returns O(1)
+  - Zero-copy mmap:  MmapStore wraps np.memmap(mode="r"), all DataLoader
+                     workers share OS page-cache pages
 """
 
 import bisect
@@ -12,6 +25,7 @@ from pathlib import Path
 from typing import Callable, Dict, List, Optional, Union
 
 import h5py
+import numpy as np
 import torch
 from torch import Tensor
 
@@ -104,6 +118,38 @@ def load_json(
     return tensor_group
 
 
+def save_bin(file_path: str, tensor_group: Dict[str, List[Tensor]]):
+    os.makedirs(file_path, exist_ok=True)
+    meta = {}
+    for key, tensors in tensor_group.items():
+        cat = torch.cat(tensors, dim=0)
+        meta[key] = {"shape": list(cat.shape), "dtype": str(cat.dtype).split(".")[-1]}
+        np.asarray(cat.cpu().numpy()).tofile(os.path.join(file_path, f"{key}.bin"))
+    save_json(meta, os.path.join(file_path, "meta.json"))
+
+
+def load_bin(file_path: str) -> Dict[str, List[Tensor]]:
+    meta = load_json(os.path.join(file_path, "meta.json"))
+    segments: Dict[str, List[Tensor]] = {}
+    for key, info in meta.items():
+        arr = np.memmap(
+            os.path.join(file_path, f"{key}.bin"),
+            dtype=info["dtype"],
+            mode="r",
+            shape=tuple(info["shape"]),
+        )
+        segments[key] = [torch.from_numpy(arr)]
+    return segments
+
+
+def json_to_bin(json_path: str, bin_path: str, tokenizer=None):
+    segments = load_json(json_path, share_memory=False, tokenizer=tokenizer)
+    merged = {}
+    for key, tensors in segments.items():
+        merged[key] = [torch.cat(tensors, dim=0)]
+    save_bin(bin_path, merged)
+
+
 def detect_format(load_path: str) -> str:
     """Auto-detect storage format from files in the directory.
 
@@ -111,7 +157,7 @@ def detect_format(load_path: str) -> str:
         load_path: Directory or file path
 
     Returns:
-        Format string ("h5" or "json")
+        Format string ("h5", "bin", or "json")
 
     Raises:
         FileNotFoundError: If no supported data files are found
@@ -128,166 +174,118 @@ def detect_format(load_path: str) -> str:
     h5_files = list(root.rglob("*.h5")) + list(root.rglob("*.hdf5"))
     if h5_files:
         return "h5"
+    bin_files = list(root.rglob("*.bin"))
+    if bin_files and (root / "meta.json").exists():
+        return "bin"
     json_files = list(root.rglob("*.json")) + list(root.rglob("*.jsonl"))
     if json_files:
         return "json"
     raise FileNotFoundError(f"No supported data files found at {load_path}")
 
 
-class BaseSegmentFetcher:
-    """Fetches data segments across multiple tensor segments.
+class Store(ABC):
+    """String keys -> segmented tensors with ``fetch(begin, end, keys)``.
 
-    Maintains cumulative lengths for efficient range queries across
-    multiple discontinuous segments.
-    """
+    Each key maps to one or more tensor segments (no forced concatenation).
+    ``len(store)`` returns ``self._length`` (explicit, O(1)), the minimum
+    total element count across all keys.
 
-    def __init__(self, segments: List[Tensor]):
-        self.segments = segments
-        self.cum_lengths = []
-
-        total = 0
-        for seg in segments:
-            total += torch.numel(seg)
-            self.cum_lengths.append(total)
-
-        self.total_length = total
-
-    def __len__(self) -> int:
-        return self.total_length
-
-    def fetch_data(self, begin_idx: int, end_idx: int) -> Tensor:
-        """Fetch data in the range [begin_idx, end_idx)."""
-        if not (
-            0 <= begin_idx < self.total_length and 0 <= end_idx <= self.total_length
-        ):
-            raise ValueError("begin_idx or end_idx out of bounds")
-        if begin_idx >= end_idx:
-            return torch.tensor([], dtype=torch.long)
-
-        seg_start_idx = bisect.bisect_right(self.cum_lengths, begin_idx)
-        seg_end_idx = bisect.bisect_left(self.cum_lengths, end_idx)
-
-        result_segments = []
-
-        for i in range(seg_start_idx, seg_end_idx + 1):
-            prev_cum = self.cum_lengths[i - 1] if i > 0 else 0
-            start = max(begin_idx - prev_cum, 0)
-            end = min(end_idx - prev_cum, len(self.segments[i]))
-            result_segments.append(self.segments[i][start:end])
-
-        return torch.cat(result_segments, dim=0)
-
-
-class MultiSegmentFetcher:
-    """Manages multiple segment fetchers for different data keys."""
-
-    def __init__(self, multi_segments: Dict):
-        self.multi_keys = list(multi_segments.keys())
-        self.multi_fetchers = {
-            key: BaseSegmentFetcher(segments)
-            for key, segments in multi_segments.items()
-        }
-
-    def __len__(self) -> int:
-        """Returns the minimum length across all fetchers."""
-        if not self.multi_fetchers:
-            return 0
-        len_list = [len(seg) for seg in self.multi_fetchers.values()]
-        return min(len_list)
-
-    def key_fetch(
-        self, begin_idx: int, end_idx: int, keys: Union[str, List[str]]
-    ) -> Dict:
-        """Fetch data for specific keys."""
-        fetch_dict = {}
-        keys = [keys] if isinstance(keys, str) else keys
-
-        for key in keys:
-            fetcher = self.multi_fetchers[key]
-            fetch_tensor = fetcher.fetch_data(begin_idx, end_idx)
-            fetch_dict[key] = fetch_tensor
-
-        return fetch_dict if len(keys) > 1 else fetch_dict[keys[0]]
-
-    def fetch_data(self, begin_idx: int, end_idx: int) -> Dict:
-        """Fetch all keys."""
-        return self.key_fetch(begin_idx, end_idx, self.multi_keys)
-
-
-class BaseStorage(ABC):
-    """Abstract storage backend for loading and dispatching data.
-
-    Storage encapsulates format-specific loading and provides a uniform
-    interface for data access and length observation. Subclasses handle
-    different data formats (HDF5, JSON, etc.) while exposing the same
-    fetch interface.
+    Subclasses fill ``self._data`` and ``self._cum`` during ``load()``
+    via ``_normalize()``.
     """
 
     def __init__(self):
-        self._fetcher: Optional[MultiSegmentFetcher] = None
+        self._data: Dict[str, List[Tensor]] = {}
+        self._cum: Dict[str, List[int]] = {}
+        self._length: int = 0
 
     @abstractmethod
-    def load(self, load_path: str, tokenizer=None) -> None:
-        """Load data from the given path into internal fetcher."""
+    def load(self, path: str, tokenizer=None) -> None:
         raise NotImplementedError
 
-    def __len__(self) -> int:
-        """Total number of raw elements (tokens) in storage."""
-        if self._fetcher is None:
-            return 0
-        return len(self._fetcher)
-
-    def fetch(self, begin_idx: int, end_idx: int, keys: Union[str, List[str]]):
-        """Fetch data for the given keys and index range.
-
-        Args:
-            begin_idx: Starting index (inclusive)
-            end_idx: Ending index (exclusive)
-            keys: Single key or list of keys to fetch
-
-        Returns:
-            Tensor if single key, Dict[str, Tensor] if multiple keys
-        """
-        if self._fetcher is None:
-            raise RuntimeError("Storage not loaded")
-        return self._fetcher.key_fetch(begin_idx, end_idx, keys)
-
     @property
     def keys(self) -> List[str]:
-        """Return the data keys available in this storage."""
-        if self._fetcher is None:
-            return []
-        return self._fetcher.multi_keys
+        return list(self._data.keys())
+
+    def __len__(self) -> int:
+        return self._length
+
+    def fetch(
+        self,
+        begin: int,
+        end: int,
+        keys: Union[str, List[str]],
+    ):
+        if not self._data:
+            raise RuntimeError("Store not loaded")
+        if not (0 <= begin < self._length and 0 <= end <= self._length):
+            raise ValueError(
+                f"Index out of bounds: begin={begin}, end={end}, length={self._length}"
+            )
+        if isinstance(keys, str):
+            return self._fetch_key(keys, begin, end)
+        return {k: self._fetch_key(k, begin, end) for k in keys}
+
+    def _fetch_key(self, key: str, begin: int, end: int) -> Tensor:
+        """Fetch slice [begin, end) across potentially multiple segments."""
+        segments = self._data[key]
+        cum = self._cum[key]
+        seg_start = bisect.bisect_right(cum, begin)
+        seg_end = bisect.bisect_left(cum, end)
+
+        results = []
+        for i in range(seg_start, seg_end + 1):
+            prev = cum[i - 1] if i > 0 else 0
+            s = max(begin - prev, 0)
+            e = min(end - prev, segments[i].shape[0])
+            results.append(segments[i][s:e])
+
+        return results[0] if len(results) == 1 else torch.cat(results, dim=0)
+
+    def _normalize(self, raw: Dict[str, List[Tensor]]):
+        """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.
+        """
+        for key, tensors in raw.items():
+            self._data[key] = tensors
+            cum = []
+            total = 0
+            for t in tensors:
+                total += t.shape[0]
+                cum.append(total)
+            self._cum[key] = cum
+        self._length = min(cum[-1] for cum in self._cum.values()) if self._cum else 0
 
 
-class StorageFactory(BaseFactory["BaseStorage"]):
-    """Factory for creating storage backends by type name.
+class StoreFactory(BaseFactory["Store"]):
+    """Factory for creating Store instances by type name.
 
-    Example:
-        @StorageFactory.register("custom")
-        class CustomStorage(BaseStorage):
+    Example::
+
+        @StoreFactory.register("custom")
+        class CustomStore(Store):
             ...
-
-        storage = StorageFactory.create("custom")
     """
 
     @classmethod
-    def _validate_component(cls, storage_cls: type) -> None:
-        if not issubclass(storage_cls, BaseStorage):
-            raise TypeError(f"{storage_cls.__name__} must inherit from BaseStorage")
+    def _validate_component(cls, store_cls: type):
+        if not issubclass(store_cls, Store):
+            raise TypeError(f"{store_cls.__name__} must inherit from Store")
 
 
-@StorageFactory.register("h5")
-class H5Storage(BaseStorage):
+@StoreFactory.register("h5")
+class H5Store(Store):
     """HDF5-based storage backend (pre-tokenized data)."""
 
-    def load(self, load_path: str, tokenizer=None) -> None:
-        segments = load_h5(load_path)
-        self._fetcher = MultiSegmentFetcher(segments)
+    def load(self, path: str, tokenizer=None):
+        self._normalize(load_h5(path))
 
 
-@StorageFactory.register("json")
-class JSONStorage(BaseStorage):
+@StoreFactory.register("json")
+class JSONStore(Store):
     """JSON-based storage backend.
 
     Supports two modes:
@@ -296,6 +294,28 @@ class JSONStorage(BaseStorage):
       callable (str -> List[int]) at load time.
     """
 
-    def load(self, load_path: str, tokenizer=None) -> None:
-        segments = load_json(load_path, tokenizer=tokenizer)
-        self._fetcher = MultiSegmentFetcher(segments)
+    def load(self, path: str, tokenizer=None):
+        self._normalize(load_json(path, tokenizer=tokenizer))
+
+
+@StoreFactory.register("bin")
+class MmapStore(Store):
+    """Memory-mapped binary storage backend.
+
+    Each key is a single .bin file backed by ``np.memmap(mode="r")``.
+    No per-process memory duplication — all DataLoader workers share the
+    same OS page-cache pages.
+
+    Format on disk::
+
+        data_root/
+          meta.json          # {key: {shape, dtype}, ...}
+          <key>.bin          # raw numpy array, one per key
+    """
+
+    def load(self, path: str, tokenizer=None):
+        self._mmap_refs = []
+        raw = load_bin(path)
+        self._normalize(raw)
+        for tensors in self._data.values():
+            self._mmap_refs.extend(tensors)

astrai/factory.py

@@ -23,7 +23,7 @@ class Registry:
         component_cls: Type,
         category: Optional[str] = None,
         priority: int = 0,
-    ) -> None:
+    ):
         """Register a component class with optional category and priority."""
         if name in self._entries:
             raise ValueError(f"Component '{name}' is already registered")
@@ -158,7 +158,7 @@ class BaseFactory(ABC, Generic[T]):
         return component_cls(*args, **kwargs)
 
     @classmethod
-    def _validate_component(cls, component_cls: Type[T]) -> None:
+    def _validate_component(cls, component_cls: Type[T]):
         """Validate that the component class is valid for this factory.
 
         Override this method in subclasses to add custom validation.

astrai/inference/core/cache.py

@@ -42,7 +42,7 @@ class Allocator:
                 return idx
             return -1
 
-    def free(self, idx: int, keep_cached: bool = False) -> None:
+    def free(self, idx: int, keep_cached: bool = False):
         with self._lock:
             self._refs[idx] -= 1
             if self._refs[idx] == 0:
@@ -51,7 +51,7 @@ class Allocator:
                 else:
                     self._free_mask |= 1 << idx
 
-    def inc_ref(self, idx: int) -> None:
+    def inc_ref(self, idx: int):
         with self._lock:
             self._refs[idx] += 1
             self._lru.pop(idx, None)
@@ -60,7 +60,7 @@ class Allocator:
         with self._lock:
             return self._refs[idx]
 
-    def touch(self, idx: int) -> None:
+    def touch(self, idx: int):
         with self._lock:
             self._lru.move_to_end(idx)
 
@@ -74,7 +74,7 @@ class PrefixCache:
         self._hash_to_page: Dict[int, int] = {}
         self._lock = threading.Lock()
 
-    def evict(self, idx: int) -> None:
+    def evict(self, idx: int):
         with self._lock:
             h = self._page_to_hash.pop(idx, None)
             if h is not None:
@@ -96,9 +96,7 @@ class PrefixCache:
                 hits.append(p)
             return hits
 
-    def record(
-        self, page_idx: int, token_ids: List[int], logical_page_idx: int
-    ) -> None:
+    def record(self, page_idx: int, token_ids: List[int], logical_page_idx: int):
         with self._lock:
             h = page_hash(token_ids, logical_page_idx, self._page_size)
             old_h = self._page_to_hash.pop(page_idx, None)
@@ -127,13 +125,13 @@ class PagePool:
     def alloc(self) -> int:
         return self._alloc.alloc()
 
-    def free(self, idx: int) -> None:
+    def free(self, idx: int):
         keep = self._prefix.has_page(idx)
         self._alloc.free(idx, keep_cached=keep)
         if not keep:
             self._prefix.evict(idx)
 
-    def inc_ref(self, idx: int) -> None:
+    def inc_ref(self, idx: int):
         self._alloc.inc_ref(idx)
 
     def lookup(self, token_ids: List[int]) -> List[int]:
@@ -142,9 +140,7 @@ class PagePool:
             self._alloc.touch(p)
         return hits
 
-    def record(
-        self, page_idx: int, token_ids: List[int], logical_page_idx: int
-    ) -> None:
+    def record(self, page_idx: int, token_ids: List[int], logical_page_idx: int):
         self._prefix.record(page_idx, token_ids, logical_page_idx)
 
 
@@ -157,7 +153,7 @@ class TaskTable:
         self._cached: Dict[str, int] = {}
         self._lock = threading.Lock()
 
-    def set(self, task_id: str, page_table: List[int], cached: int) -> None:
+    def set(self, task_id: str, page_table: List[int], cached: int):
         with self._lock:
             self._pages[task_id] = page_table
             self._cached[task_id] = cached
@@ -220,7 +216,7 @@ class Storage:
         start_pos: int,
         k: Tensor,
         v: Tensor,
-    ) -> None:
+    ):
         seq_len = k.size(1)
         if seq_len == 0:
             return
@@ -286,7 +282,7 @@ class KvcacheView:
         self._page_table = page_table
         self._total_len = total_len
 
-    def write(self, layer_id: int, k: Tensor, v: Tensor) -> None:
+    def write(self, layer_id: int, k: Tensor, v: Tensor):
         start_pos = self._total_len - k.size(1)
         self._storage.write(layer_id, self._page_table, start_pos, k, v)
 
@@ -339,7 +335,7 @@ class KVCache:
         self._table.set(task_id, hits + new_pages, cached)
         return True
 
-    def task_free(self, task_id: str) -> None:
+    def task_free(self, task_id: str):
         page_table, _ = self._table.pop(task_id)
         for idx in page_table:
             self._pool.free(idx)
@@ -359,7 +355,7 @@ class KVCache:
 
     def task_record_hashes(
         self, task_id: str, prompt_ids: List[int], start_logical_page: int = 0
-    ) -> None:
+    ):
         page_table = self._table.get(task_id)
         full_pages = len(prompt_ids) // self.page_size
         for i in range(start_logical_page, full_pages):

astrai/inference/core/executor.py

@@ -29,9 +29,7 @@ class Executor:
         self.device = device or next(model.parameters()).device
         self.dtype = dtype or next(model.parameters()).dtype
 
-    def execute_prefill(
-        self, tasks: List[Task], prompt_len: int, start_pos: int = 0
-    ) -> None:
+    def execute_prefill(self, tasks: List[Task], prompt_len: int, start_pos: int = 0):
         if start_pos >= prompt_len:
             return
 

astrai/inference/core/scheduler.py

@@ -75,14 +75,14 @@ class InferenceScheduler:
     def add_task(self, prompt: str, **kwargs) -> str:
         return self._task_mgr.add_task(prompt, **kwargs)
 
-    def remove_task(self, task_id: str) -> None:
+    def remove_task(self, task_id: str):
         for task in self._task_mgr.remove_task(task_id):
             self._page_cache.task_free(task.task_id)
 
     def get_stats(self) -> Dict[str, Any]:
         return self._task_mgr.get_stats()
 
-    def _run_generation_loop(self) -> None:
+    def _run_generation_loop(self):
         stop_ids = self._task_mgr.tokenizer.stop_ids
         try:
             while self._running:
@@ -186,14 +186,14 @@ class InferenceScheduler:
             self._task_mgr.clear_queues()
             raise
 
-    def start(self) -> None:
+    def start(self):
         if not self._running:
             self._running = True
             t = threading.Thread(target=self._run_generation_loop, daemon=True)
             t.start()
             self._loop_thread = t
 
-    def stop(self) -> None:
+    def stop(self):
         self._running = False
         self._task_mgr.wake()
         if hasattr(self, "_loop_thread"):

astrai/inference/core/task.py

@@ -172,12 +172,12 @@ class TaskManager:
                 to_add.append(self.waiting_queue.popleft())
         return to_add
 
-    def activate(self, task: Task) -> None:
+    def activate(self, task: Task):
         task.status = TaskStatus.RUNNING
         with self._lock:
             self.active_tasks.append(task)
 
-    def return_to_waiting(self, tasks: List[Task]) -> None:
+    def return_to_waiting(self, tasks: List[Task]):
         with self._lock:
             for task in reversed(tasks):
                 self.waiting_queue.appendleft(task)
@@ -185,7 +185,7 @@ class TaskManager:
     def has_work(self) -> bool:
         return bool(self.active_tasks or self.waiting_queue)
 
-    def wait_for_tasks(self, timeout: float = 1.0) -> None:
+    def wait_for_tasks(self, timeout: float = 1.0):
         self._task_event.clear()
         self._task_event.wait(timeout=timeout)
 
@@ -197,10 +197,10 @@ class TaskManager:
         with self._lock:
             return list(self.waiting_queue)
 
-    def clear_queues(self) -> None:
+    def clear_queues(self):
         with self._lock:
             self.waiting_queue.clear()
             self.active_tasks.clear()
 
-    def wake(self) -> None:
+    def wake(self):
         self._task_event.set()

astrai/inference/engine.py

@@ -48,7 +48,7 @@ class GenerateResult:
     def wait(self, timeout: Optional[float] = None) -> bool:
         return self._event.wait(timeout=timeout)
 
-    def wait_completion(self, timeout: float = 300.0) -> None:
+    def wait_completion(self, timeout: float = 300.0):
         with self._cond:
             if not self._cond.wait_for(
                 lambda: self._completed >= self._total, timeout=timeout
@@ -281,7 +281,7 @@ class InferenceEngine:
     def get_stats(self) -> Dict[str, Any]:
         return self.scheduler.get_stats()
 
-    def shutdown(self) -> None:
+    def shutdown(self):
         self.scheduler.stop()
         if torch.cuda.is_available():
             torch.cuda.empty_cache()

astrai/model/automodel.py

@@ -15,7 +15,11 @@ from astrai.serialization import load_model_config, load_model_weights, save_mod
 
 @contextmanager
 def _disable_random_init(enable: bool = True):
-    init_functions = [
+    if not enable:
+        yield
+        return
+
+    names = (
         "xavier_normal_",
         "xavier_uniform_",
         "kaiming_normal_",
@@ -25,18 +29,15 @@ def _disable_random_init(enable: bool = True):
         "constant_",
         "normal_",
         "uniform_",
-    ]
-    original_funcs = {}
-    for name in init_functions:
-        if enable and hasattr(nn.init, name):
-            original_funcs[name] = getattr(nn.init, name)
-            setattr(nn.init, name, lambda *args, **kwargs: None)
+    )
+    orig = {n: getattr(nn.init, n) for n in names if hasattr(nn.init, n)}
+    for n in orig:
+        setattr(nn.init, n, lambda *a, **kw: None)
     try:
         yield
     finally:
-        if enable:
-            for name, orig_func in original_funcs.items():
-                setattr(nn.init, name, orig_func)
+        for n, fn in orig.items():
+            setattr(nn.init, n, fn)
 
 
 class AutoModel(BaseFactory["AutoModel"], nn.Module):
@@ -82,7 +83,7 @@ class AutoModel(BaseFactory["AutoModel"], nn.Module):
     def save_pretrained(
         self,
         save_directory: Union[str, Path],
-    ) -> None:
+    ):
         save_model(
             config=self.config.to_dict(),
             state_dict=self.state_dict(),

astrai/model/encoder.py

@@ -68,9 +68,6 @@ class EmbeddingEncoder(AutoModel):
 
         x = self.embed_tokens(input_ids)
 
-        if position_ids is None:
-            position_ids = torch.arange(S, device=x.device).unsqueeze(0).expand(B, -1)
-
         rotary_emb = self.rotary_embedding(x, position_ids)
         attn_mask = process_attention_mask(x, position_ids, input_mask, is_causal=False)
 

astrai/model/transformer.py

@@ -1,4 +1,4 @@
-from typing import Any, Mapping, Optional
+from typing import Any, Dict, Mapping, Optional
 
 import torch
 import torch.nn as nn
@@ -136,7 +136,7 @@ class AutoRegressiveLM(AutoModel):
         input_mask: Optional[Tensor] = None,
         paged_cache: Optional[KvcacheView] = None,
         position_ids: Optional[Tensor] = None,
-    ) -> Tensor:
+    ) -> Dict[str, Tensor]:
         assert input_ids.ndim == 2
 
         x = self.embed_tokens(input_ids)

astrai/parallel/executor.py

@@ -203,9 +203,45 @@ class DDPExecutor(BaseExecutor):
 
 @ExecutorFactory.register("fsdp")
 class FSDPExecutor(BaseExecutor):
-    def __init__(self, grad_accum_steps: int = 1, **fsdp_kwargs):
+    def __init__(
+        self,
+        grad_accum_steps: int = 1,
+        process_group=None,
+        sharding_strategy=None,
+        cpu_offload=None,
+        auto_wrap_policy=None,
+        backward_prefetch=None,
+        mixed_precision=None,
+        ignored_modules=None,
+        param_init_fn=None,
+        sync_module_states: bool = False,
+        forward_prefetch: bool = False,
+        limit_all_gathers: bool = True,
+        use_orig_params: bool = False,
+        ignored_states=None,
+        device_mesh=None,
+    ):
         super().__init__(grad_accum_steps=grad_accum_steps)
-        self._fsdp_kwargs = fsdp_kwargs
+        self._fsdp_kwargs = {
+            k: v
+            for k, v in dict(
+                process_group=process_group,
+                sharding_strategy=sharding_strategy,
+                cpu_offload=cpu_offload,
+                auto_wrap_policy=auto_wrap_policy,
+                backward_prefetch=backward_prefetch,
+                mixed_precision=mixed_precision,
+                ignored_modules=ignored_modules,
+                param_init_fn=param_init_fn,
+                sync_module_states=sync_module_states,
+                forward_prefetch=forward_prefetch,
+                limit_all_gathers=limit_all_gathers,
+                use_orig_params=use_orig_params,
+                ignored_states=ignored_states,
+                device_mesh=device_mesh,
+            ).items()
+            if v is not None
+        }
         self._original_model: Optional[nn.Module] = None
 
     def _prepare_model(self, model: nn.Module) -> nn.Module:

astrai/serialization.py

@@ -1,8 +1,9 @@
+import io
 import json
 import time
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Any, Dict
+from typing import Any, Dict, List, Tuple
 
 import safetensors.torch as st
 import torch
@@ -11,11 +12,11 @@ import torch.distributed as dist
 from astrai.parallel.setup import get_rank
 
 _META_FILE = "meta.json"
+_CONFIG_FILE = "config.json"
 _WEIGHTS_FILE = "model.safetensors"
-_MODEL_CONFIG_FILE = "config.json"
 
 
-def save_safetensors(state_dict: dict, path: str | Path) -> None:
+def save_safetensors(state_dict: dict, path: str | Path):
     st.save_file(state_dict, str(path))
 
 
@@ -23,7 +24,7 @@ def load_safetensors(path: str | Path) -> dict:
     return st.load_file(str(path))
 
 
-def save_json(data: dict, path: str | Path) -> None:
+def save_json(data: dict, path: str | Path):
     with open(str(path), "w") as f:
         json.dump(data, f, indent=2)
 
@@ -33,13 +34,92 @@ def load_json(path: str | Path) -> dict:
         return json.load(f)
 
 
-def save_torch(obj: Any, path: str | Path) -> None:
+def save_torch(obj: Any, path: str | Path):
     torch.save(obj, str(path))
 
 
-def load_torch(path: str | Path) -> Any:
+def load_torch(path: str | Path, broadcast: bool = False) -> Any:
+    if not broadcast or not dist.is_initialized():
         return torch.load(str(path), map_location="cpu", weights_only=False)
 
+    path = Path(path)
+    rank = get_rank()
+
+    if rank == 0:
+        with open(path, "rb") as f:
+            raw = f.read()
+        data_tensor = torch.frombuffer(bytearray(raw), dtype=torch.uint8)
+        num_bytes = torch.tensor([len(raw)], dtype=torch.long)
+    else:
+        num_bytes = torch.tensor([0], dtype=torch.long)
+
+    dist.broadcast(num_bytes, src=0)
+
+    if rank != 0:
+        data_tensor = torch.empty(num_bytes.item(), dtype=torch.uint8)
+
+    dist.broadcast(data_tensor, src=0)
+
+    buf = io.BytesIO(data_tensor.numpy().tobytes())
+    return torch.load(buf, map_location="cpu", weights_only=False)
+
+
+def save_model(config: dict, state_dict: dict, save_directory: str):
+    save_path = Path(save_directory)
+    save_path.mkdir(parents=True, exist_ok=True)
+    save_json(config, save_path / _CONFIG_FILE)
+    save_safetensors(state_dict, save_path / _WEIGHTS_FILE)
+
+
+def load_model_config(save_directory: str) -> dict:
+    return load_json(Path(save_directory) / _CONFIG_FILE)
+
+
+def load_model_weights(save_directory: str) -> dict:
+    return load_safetensors(Path(save_directory) / _WEIGHTS_FILE)
+
+
+def _get_meta(save_path: Path) -> dict:
+    meta = {}
+    if get_rank() == 0:
+        meta = load_json(save_path / _META_FILE)
+    if dist.is_initialized():
+        meta_list = [meta]
+        dist.broadcast_object_list(meta_list, src=0)
+        meta = meta_list[0]
+    return meta
+
+
+def _load_state_dict(save_path: Path, broadcast: bool = False) -> dict:
+    if not broadcast or not dist.is_initialized():
+        return load_safetensors(save_path / _WEIGHTS_FILE)
+
+    rank = get_rank()
+    if rank == 0:
+        state_dict = load_safetensors(save_path / _WEIGHTS_FILE)
+        specs: List[Tuple[str, List[int], str]] = [
+            (k, list(state_dict[k].shape), str(state_dict[k].dtype).split(".")[-1])
+            for k in sorted(state_dict)
+        ]
+    else:
+        state_dict = {}
+        specs = []
+
+    specs_list = [specs]
+    dist.broadcast_object_list(specs_list, src=0)
+    specs = specs_list[0]
+
+    for key, shape, dtype_name in specs:
+        dtype = getattr(torch, dtype_name)
+        if rank != 0:
+            tensor = torch.empty(shape, dtype=dtype, device="cpu")
+        else:
+            tensor = state_dict[key].contiguous().cpu()
+        dist.broadcast(tensor, src=0)
+        if rank != 0:
+            state_dict[key] = tensor
+    return state_dict
+
 
 @dataclass
 class Checkpoint:
@@ -49,7 +129,7 @@ class Checkpoint:
     extra: Dict[str, Any] = field(default_factory=dict)
     meta: Dict[str, Any] = field(default_factory=dict)
 
-    def save(self, save_dir: str) -> None:
+    def save(self, save_dir: str):
         save_path = Path(save_dir)
         save_path.mkdir(parents=True, exist_ok=True)
 
@@ -68,24 +148,16 @@ class Checkpoint:
             save_torch(value, save_path / f"{key}.pt")
 
     @classmethod
-    def load(cls, save_dir: str) -> "Checkpoint":
+    def load(cls, save_dir: str, broadcast: bool = False) -> "Checkpoint":
         save_path = Path(save_dir)
 
-        meta = {}
-        if get_rank() == 0:
-            meta = load_json(save_path / _META_FILE)
-
-        if dist.is_initialized():
-            meta_list = [meta]
-            dist.broadcast_object_list(meta_list, src=0)
-            meta = meta_list[0]
-
-        state_dict = load_safetensors(save_path / _WEIGHTS_FILE)
+        meta = _get_meta(save_path)
+        state_dict = _load_state_dict(save_path, broadcast=broadcast)
 
         extra = {}
-        for f in save_path.iterdir():
+        for f in sorted(save_path.iterdir()):
             if f.suffix == ".pt":
-                extra[f.stem] = load_torch(f)
+                extra[f.stem] = load_torch(f, broadcast=broadcast)
 
         return cls(
             state_dict=state_dict,
@@ -93,18 +165,3 @@ class Checkpoint:
             iteration=meta.get("iteration", 0),
             extra=extra,
         )
-
-
-def save_model(config: dict, state_dict: dict, save_directory: str) -> None:
-    save_path = Path(save_directory)
-    save_path.mkdir(parents=True, exist_ok=True)
-    save_json(config, save_path / _MODEL_CONFIG_FILE)
-    save_safetensors(state_dict, save_path / _WEIGHTS_FILE)
-
-
-def load_model_config(save_directory: str) -> dict:
-    return load_json(Path(save_directory) / _MODEL_CONFIG_FILE)
-
-
-def load_model_weights(save_directory: str) -> dict:
-    return load_safetensors(Path(save_directory) / _WEIGHTS_FILE)

astrai/trainer/schedule.py

@@ -42,7 +42,7 @@ class SchedulerFactory(BaseFactory["BaseScheduler"]):
     """
 
     @classmethod
-    def _validate_component(cls, scheduler_cls: Type[BaseScheduler]) -> None:
+    def _validate_component(cls, scheduler_cls: Type[BaseScheduler]):
         """Validate that the scheduler class inherits from BaseScheduler."""
         if not issubclass(scheduler_cls, BaseScheduler):
             raise TypeError(f"{scheduler_cls.__name__} must inherit from BaseScheduler")

astrai/trainer/strategy.py

@@ -125,7 +125,7 @@ class StrategyFactory(BaseFactory["BaseStrategy"]):
     """
 
     @classmethod
-    def _validate_component(cls, strategy_cls: type) -> None:
+    def _validate_component(cls, strategy_cls: type):
         """Validate that the strategy class inherits from BaseStrategy."""
         if not issubclass(strategy_cls, BaseStrategy):
             raise TypeError(f"{strategy_cls.__name__} must inherit from BaseStrategy")

astrai/trainer/train_callback.py

@@ -15,7 +15,7 @@ from tqdm import tqdm
 
 from astrai.factory import BaseFactory
 from astrai.parallel import only_on_rank
-from astrai.parallel.setup import get_current_device
+from astrai.parallel.setup import get_current_device, get_rank
 from astrai.serialization import Checkpoint
 from astrai.trainer.metric_util import (
     ctx_get_grad_max,
@@ -139,27 +139,27 @@ class CheckpointCallback(TrainCallback):
         weight_only: bool = False,
         state_dict_fn: Optional[Callable[[nn.Module], dict]] = None,
         save_extra_fn: Optional[Callable[["TrainContext"], dict]] = None,
-        load_extra_fn: Optional[Callable[[dict, "TrainContext"], None]] = None,
     ):
         self.save_dir = save_dir
         self.interval = interval
         self.weight_only = weight_only
         self.state_dict_fn = state_dict_fn
         self.save_extra_fn = save_extra_fn or CheckpointCallback.save_extra
-        self.load_extra_fn = load_extra_fn or CheckpointCallback.load_extra
         self.last_ckpt_iter = 0
 
-    @only_on_rank(0)
     def _save_checkpoint(self, context: TrainContext):
-        save_path = os.path.join(
-            self.save_dir, f"epoch_{context.epoch}_iter_{context.iteration}"
-        )
+        # All ranks gather state_dict — collective for FSDP, local for DDP
         state_dict = (
             self.state_dict_fn(context.model)
             if self.state_dict_fn
             else context.model.state_dict()
         )
+        self.last_ckpt_iter = context.iteration
 
+        if get_rank() == 0:
+            save_path = os.path.join(
+                self.save_dir, f"epoch_{context.epoch}_iter_{context.iteration}"
+            )
             extra = self.save_extra_fn(context)
             context.checkpoint = Checkpoint(
                 state_dict=state_dict,
@@ -168,13 +168,7 @@ class CheckpointCallback(TrainCallback):
                 extra=extra,
                 meta=context.config.to_dict(),
             )
-
             context.checkpoint.save(save_path)
-        self.last_ckpt_iter = context.iteration
-
-    def on_train_begin(self, context: TrainContext):
-        if context.checkpoint and context.checkpoint.extra:
-            self.load_extra_fn(context.checkpoint.extra, context)
 
     def on_batch_end(self, context: TrainContext):
         if context.iteration - self.last_ckpt_iter >= self.interval:
@@ -196,12 +190,6 @@ class CheckpointCallback(TrainCallback):
                 extra[name] = obj.state_dict()
         return extra
 
-    @staticmethod
-    def load_extra(extra: dict, context: TrainContext):
-        for name in CheckpointCallback.extra_keys:
-            if name in extra:
-                getattr(context, name).load_state_dict(extra[name])
-
 
 @CallbackFactory.register("progress_bar")
 class ProgressBarCallback(TrainCallback):

astrai/trainer/train_context.py

@@ -1,4 +1,5 @@
 from dataclasses import dataclass, field
+from pathlib import Path
 from typing import Optional, Self
 
 import torch.nn as nn
@@ -10,7 +11,7 @@ from astrai.model.components.lora import inject_lora
 from astrai.parallel.executor import BaseExecutor, ExecutorFactory
 from astrai.parallel.setup import get_current_device, get_rank, get_world_size
 from astrai.protocols import OptimizerProtocol, SchedulerProtocol
-from astrai.serialization import Checkpoint
+from astrai.serialization import Checkpoint, load_model_weights
 from astrai.trainer.strategy import BaseStrategy, StrategyFactory
 
 
@@ -42,10 +43,10 @@ class TrainContextBuilder:
         config: TrainConfig,
     ):
         self.config = config
-        self._checkpoint: Optional[Checkpoint] = None
+        self._resume_dir: Optional[str] = None
 
-    def with_checkpoint(self, checkpoint: Optional[Checkpoint]) -> Self:
-        self._checkpoint = checkpoint
+    def with_resume_dir(self, resume_dir: Optional[str]) -> Self:
+        self._resume_dir = resume_dir
         return self
 
     def build(self) -> TrainContext:
@@ -58,36 +59,40 @@ class TrainContextBuilder:
             **cfg.executor_kwargs,
         )
 
+        model = cfg.model_fn()
+        model = model.to(device=device)
+
         context = TrainContext(
-            model=cfg.model,
+            model=model,
             world_size=get_world_size(),
             rank=get_rank(),
             config=cfg,
             executor=executor,
         )
 
-        context.model = context.model.to(device=device)
-
-        if self._checkpoint is not None:
-            context.epoch = max(self._checkpoint.epoch, cfg.start_epoch)
-            context.iteration = max(self._checkpoint.iteration, cfg.start_batch)
-            if self._checkpoint.state_dict:
-                context.model.load_state_dict(self._checkpoint.state_dict)
-            context.checkpoint = self._checkpoint
+        if self._resume_dir is not None:
+            resume_path = Path(self._resume_dir)
+            if (resume_path / "meta.json").exists():
+                checkpoint = Checkpoint.load(self._resume_dir)
+                state_dict = checkpoint.state_dict
             else:
-            context.checkpoint = Checkpoint(
-                state_dict=context.model.state_dict(),
-            )
+                checkpoint = None
+                state_dict = load_model_weights(self._resume_dir)
+            model.load_state_dict(state_dict, strict=False)
+            if checkpoint is not None:
+                context.epoch = max(checkpoint.epoch, cfg.start_epoch)
+                context.iteration = max(checkpoint.iteration, cfg.start_batch)
+            context.checkpoint = checkpoint
 
         if cfg.lora is not None:
             inject_lora(
-                context.model,
+                model,
                 r=cfg.lora.r,
                 alpha=cfg.lora.alpha,
                 target_modules=set(cfg.lora.target_modules),
             )
 
-        context.optimizer = cfg.optimizer_fn(context.model)
+        context.optimizer = cfg.optimizer_fn(model)
         context.scheduler = cfg.scheduler_fn(context.optimizer)
 
         sampler_offset = context.iteration * cfg.batch_per_device
@@ -125,13 +130,21 @@ class TrainContextBuilder:
 
         context.model, context.optimizer, context.dataloader, context.scheduler = (
             executor.prepare(
-                context.model,
+                model,
                 context.optimizer,
                 context.dataloader,
                 context.scheduler,
             )
         )
 
+        if context.checkpoint and context.checkpoint.extra:
+            extra = context.checkpoint.extra
+            for name in ("optimizer", "scheduler"):
+                if name in extra:
+                    obj = getattr(context, name, None)
+                    if obj is not None:
+                        obj.load_state_dict(extra[name])
+
         context.strategy = StrategyFactory.create(
             model=context.model,
             train_type=cfg.strategy,

astrai/trainer/trainer.py

@@ -3,7 +3,6 @@ from typing import List, Optional
 
 from astrai.config import TrainConfig
 from astrai.parallel.setup import spawn_parallel_fn
-from astrai.serialization import Checkpoint
 from astrai.trainer.train_callback import (
     CallbackFactory,
     TrainCallback,
@@ -54,9 +53,9 @@ class Trainer:
             if method:
                 method(context)
 
-    def _trainer_loop(self, checkpoint: Optional[Checkpoint] = None):
+    def _trainer_loop(self, resume_dir: Optional[str] = None):
         context = (
-            TrainContextBuilder(self.train_config).with_checkpoint(checkpoint).build()
+            TrainContextBuilder(self.train_config).with_resume_dir(resume_dir).build()
         )
         executor = context.executor
         self._call_callbacks("on_train_begin", context)
@@ -90,13 +89,13 @@ class Trainer:
                 self._call_callbacks("on_epoch_end", context)
 
         except Exception as e:
-            logger.error(f"Training failed: {str(e)}", exc_info=True)
+            logger.error("Training failed: %s", str(e), exc_info=True)
             self._call_callbacks("on_error", context)
             raise
         finally:
             self._call_callbacks("on_train_end", context)
 
-    def train(self, checkpoint: Optional[Checkpoint] = None):
+    def train(self, resume_dir: Optional[str] = None):
         cfg = self.train_config
         spawn_parallel_fn(
             self._trainer_loop,
@@ -106,5 +105,5 @@ class Trainer:
             master_port=cfg.master_port,
             device_type=cfg.device_type,
             start_method=cfg.start_method,
-            checkpoint=checkpoint,
+            resume_dir=resume_dir,
         )

scripts/tools/evaluate_mmlu.py

@@ -0,0 +1,279 @@
+"""MMLU evaluation via log-likelihood ranking."""
+
+import argparse
+import csv
+import json
+import os
+import shutil
+import urllib.request
+import zipfile
+
+import torch
+import torch.nn.functional as F
+import tqdm
+
+from astrai.model import AutoModel
+from astrai.tokenize import AutoTokenizer
+
+MMLU_URL = "https://github.com/hendrycks/test/archive/refs/heads/master.zip"
+MMLU_SUBJECTS = [
+    "abstract_algebra",
+    "anatomy",
+    "astronomy",
+    "business_ethics",
+    "clinical_knowledge",
+    "college_biology",
+    "college_chemistry",
+    "college_computer_science",
+    "college_mathematics",
+    "college_medicine",
+    "college_physics",
+    "computer_security",
+    "conceptual_physics",
+    "econometrics",
+    "electrical_engineering",
+    "elementary_mathematics",
+    "formal_logic",
+    "global_facts",
+    "high_school_biology",
+    "high_school_chemistry",
+    "high_school_computer_science",
+    "high_school_european_history",
+    "high_school_geography",
+    "high_school_government_and_politics",
+    "high_school_macroeconomics",
+    "high_school_mathematics",
+    "high_school_microeconomics",
+    "high_school_physics",
+    "high_school_psychology",
+    "high_school_statistics",
+    "high_school_us_history",
+    "high_school_world_history",
+    "human_aging",
+    "human_sexuality",
+    "international_law",
+    "jurisprudence",
+    "logical_fallacies",
+    "machine_learning",
+    "management",
+    "marketing",
+    "medical_genetics",
+    "miscellaneous",
+    "moral_disputes",
+    "moral_scenarios",
+    "nutrition",
+    "philosophy",
+    "prehistory",
+    "professional_accounting",
+    "professional_law",
+    "professional_medicine",
+    "professional_psychology",
+    "public_relations",
+    "security_studies",
+    "sociology",
+    "us_foreign_policy",
+    "virology",
+    "world_religions",
+]
+
+
+def _download_and_extract(url: str, data_dir: str):
+    zip_path = os.path.join(data_dir, "mmlu.zip")
+    os.makedirs(data_dir, exist_ok=True)
+    print(f"Downloading MMLU data from {url}...")
+    urllib.request.urlretrieve(url, zip_path)
+    print("Extracting...")
+    with zipfile.ZipFile(zip_path, "r") as zf:
+        zf.extractall(data_dir)
+    os.remove(zip_path)
+
+
+def download_mmlu(data_dir: str):
+    _download_and_extract(MMLU_URL, data_dir)
+    src = os.path.join(data_dir, "test-master", "data")
+    if os.path.exists(src):
+        for item in os.listdir(src):
+            os.rename(os.path.join(src, item), os.path.join(data_dir, item))
+        shutil.rmtree(os.path.join(data_dir, "test-master"))
+    print(f"MMLU data saved to {data_dir}")
+
+
+def _strip_prefix(text: str, prefix: str) -> str:
+    if text.startswith(prefix):
+        return text[len(prefix) :].strip()
+    return text
+
+
+def load_csv(path: str) -> list[dict]:
+    data = []
+    with open(path, "r", encoding="utf-8") as f:
+        for row in csv.reader(f):
+            if len(row) < 6:
+                continue
+            if row[0].strip().lower() == "question":
+                continue
+            data.append(
+                {
+                    "question": row[0].strip(),
+                    "A": _strip_prefix(row[1].strip(), "A)"),
+                    "B": _strip_prefix(row[2].strip(), "B)"),
+                    "C": _strip_prefix(row[3].strip(), "C)"),
+                    "D": _strip_prefix(row[4].strip(), "D)"),
+                    "answer": row[5].strip(),
+                }
+            )
+    return data
+
+
+def build_prompt(
+    question: str, choices: dict, subject: str, n_shot: int, dev_data: list[dict]
+) -> str:
+    prompt = ""
+    if n_shot > 0 and dev_data:
+        prompt = f"The following are multiple choice questions (with answers) about {subject}.\n\n"
+        for item in dev_data[:n_shot]:
+            prompt += f"Question: {item['question']}\n"
+            for k in ("A", "B", "C", "D"):
+                prompt += f"{k}. {item[k]}\n"
+            prompt += f"Answer: {item['answer']}\n\n"
+    prompt += f"Question: {question}\n"
+    for k in ("A", "B", "C", "D"):
+        prompt += f"{k}. {choices[k]}\n"
+    prompt += "Answer:"
+    return prompt
+
+
+def choice_logprob(
+    model, tokenizer, context_ids: list[int], choice_letter: str, device: str
+) -> float:
+    choice_text = f" {choice_letter}"
+    choice_ids = tokenizer.encode(choice_text, add_special_tokens=False)
+    input_ids = context_ids + choice_ids
+    max_len = model.config.max_len
+    if len(input_ids) > max_len:
+        overflow = len(input_ids) - max_len
+        input_ids = input_ids[overflow:]
+        ctx_len = len(input_ids) - len(choice_ids)
+    else:
+        ctx_len = len(context_ids)
+
+    input_tensor = torch.tensor([input_ids], device=device, dtype=torch.long)
+    with torch.inference_mode():
+        logits = model(input_tensor)["logits"][0]
+
+    score = 0.0
+    for i, tid in enumerate(choice_ids):
+        pos = ctx_len - 1 + i
+        if pos >= len(logits):
+            break
+        score += F.log_softmax(logits[pos], dim=-1)[tid].item()
+    return score
+
+
+def evaluate_subject(
+    model,
+    tokenizer,
+    subject: str,
+    test_data: list[dict],
+    dev_data: list[dict] | None,
+    device: str,
+    n_shot: int,
+) -> tuple[float, int, int]:
+    correct = 0
+    total = 0
+    for item in tqdm.tqdm(test_data, desc=f"{subject:40s}", leave=False):
+        prompt = build_prompt(item["question"], item, subject, n_shot, dev_data or [])
+        context_ids = tokenizer.encode(prompt)
+        scores = {
+            c: choice_logprob(model, tokenizer, context_ids, c, device)
+            for c in ("A", "B", "C", "D")
+        }
+        if max(scores, key=scores.get) == item["answer"]:
+            correct += 1
+        total += 1
+    return correct / total, correct, total
+
+
+def main():
+    parser = argparse.ArgumentParser(description="MMLU evaluation")
+    parser.add_argument(
+        "--param_path", type=str, default="./params", help="Model directory"
+    )
+    parser.add_argument(
+        "--data_dir", type=str, default="./mmlu_data", help="MMLU data directory"
+    )
+    parser.add_argument("--download", action="store_true", help="Download MMLU data")
+    parser.add_argument(
+        "--n_shot", type=int, default=5, help="Few-shot examples (0 for zero-shot)"
+    )
+    parser.add_argument(
+        "--subjects", type=str, nargs="+", help="Specific subjects (default: all)"
+    )
+    parser.add_argument("--output", type=str, help="Output JSON path")
+    parser.add_argument("--split", type=str, default="test", choices=["test", "val"])
+    parser.add_argument(
+        "--device",
+        type=str,
+        default="cuda" if torch.cuda.is_available() else "cpu",
+        help="Device",
+    )
+    parser.add_argument(
+        "--dtype",
+        type=str,
+        default="bfloat16" if torch.cuda.is_available() else "float32",
+        help="Torch dtype",
+    )
+    args = parser.parse_args()
+
+    if args.download or not os.path.exists(args.data_dir):
+        download_mmlu(args.data_dir)
+
+    model = AutoModel.from_pretrained(args.param_path)
+    tokenizer = AutoTokenizer.from_pretrained(args.param_path)
+    device = args.device
+    dtype = getattr(torch, args.dtype)
+    model.to(device=device, dtype=dtype)
+
+    subjects = args.subjects or MMLU_SUBJECTS
+    results = {}
+    total_correct = 0
+    total_questions = 0
+
+    for subject in subjects:
+        dev_path = os.path.join(args.data_dir, "dev", f"{subject}_dev.csv")
+        test_path = os.path.join(
+            args.data_dir, args.split, f"{subject}_{args.split}.csv"
+        )
+
+        if not os.path.exists(test_path):
+            print(f"  Skipping {subject}: test file not found")
+            continue
+
+        dev_data = load_csv(dev_path) if os.path.exists(dev_path) else None
+        test_data = load_csv(test_path)
+
+        acc, corr, tot = evaluate_subject(
+            model, tokenizer, subject, test_data, dev_data, device, args.n_shot
+        )
+        results[subject] = {"accuracy": round(acc, 4), "correct": corr, "total": tot}
+        total_correct += corr
+        total_questions += tot
+        print(f"  {subject:40s}  {acc:.2%}  ({corr}/{tot})")
+
+    overall = total_correct / total_questions if total_questions else 0
+    print(f"\n{'=' * 70}")
+    print(f"  Overall: {overall:.2%}  ({total_correct}/{total_questions})")
+    results["_overall"] = {
+        "accuracy": round(overall, 4),
+        "correct": total_correct,
+        "total": total_questions,
+    }
+
+    if args.output:
+        with open(args.output, "w", encoding="utf-8") as f:
+            json.dump(results, f, indent=2)
+        print(f"Results saved to {args.output}")
+
+
+if __name__ == "__main__":
+    main()

scripts/tools/perplexity.py

@@ -10,11 +10,11 @@ from astrai.tokenize import AutoTokenizer
 
 
 def process_file(
-    model_dir: str, input_file: str, output_file: str, batch_size: int, text_key: str
+    param_path: str, input_file: str, output_file: str, batch_size: int, text_key: str
 ):
     # Load model and tokenizer
-    model = AutoModel.from_pretrained(model_dir)
-    tokenizer = AutoTokenizer.from_pretrained(model_dir)
+    model = AutoModel.from_pretrained(param_path)
+    tokenizer = AutoTokenizer.from_pretrained(param_path)
     model.to(device="cuda", dtype=torch.bfloat16)
 
     with open(input_file, "r", encoding="utf-8") as f:
@@ -44,8 +44,8 @@ def process_file(
 
         for seq in batch_encoded:
             pad_len = max_len - len(seq)
-            padded_seq = [tokenizer.pad_id] * pad_len + seq
-            mask = [False] * pad_len + [True] * len(seq)
+            padded_seq = seq + [tokenizer.pad_id] * pad_len
+            mask = [True] * len(seq) + [False] * pad_len
             padded_ids.append(padded_seq)
             masks.append(mask)
 
@@ -88,7 +88,7 @@ def process_file(
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Run perplexity with a Khaosz model.")
     parser.add_argument(
-        "--model_dir", type=str, required=True, help="Path to the model directory."
+        "--param_path", type=str, required=True, help="Path to the model directory."
     )
     parser.add_argument(
         "--input_file", type=str, required=True, help="Path to the input file."

scripts/tools/server.py

@@ -18,7 +18,7 @@ def main():
         "--reload", action="store_true", help="Enable auto-reload for development"
     )
     parser.add_argument(
-        "--param-path",
+        "--param_path",
         type=Path,
         default=None,
         help="Path to model parameters (default: project_root/params)",

scripts/tools/train.py

@@ -8,7 +8,6 @@ import torch.optim as optim
 from astrai.config import AutoRegressiveLMConfig, TrainConfig
 from astrai.dataset import DatasetFactory
 from astrai.model import AutoRegressiveLM
-from astrai.serialization import Checkpoint
 from astrai.trainer import SchedulerFactory, Trainer
 
 
@@ -147,8 +146,8 @@ def parse_args() -> argparse.Namespace:
         "--parallel_mode",
         type=str,
         default="none",
-        choices=["none", "ddp"],
-        help="Parallel training strategy.",
+        choices=["none", "ddp", "fsdp"],
+        help="Parallel training strategy (none, ddp, fsdp).",
     )
     parser.add_argument(
         "--device_type", type=str, default="cuda", help="Device type to use."
@@ -166,6 +165,10 @@ def parse_args() -> argparse.Namespace:
     return args
 
 
+def create_model(config):
+    return AutoRegressiveLM(config).to(dtype=torch.bfloat16)
+
+
 def create_optimizer(model, **kwargs) -> optim.Optimizer:
     return optim.AdamW(model.parameters(), fused=True, **kwargs)
 
@@ -228,6 +231,8 @@ def train(
 ):
     assert train_type in ["seq", "sft", "dpo", "grpo"]
     assert os.path.exists(param_path)
+    if nprocs > 1 and parallel_mode == "none":
+        raise ValueError("--nprocs > 1 requires --parallel_mode to be 'ddp' or 'fsdp'")
 
     # Load config
     config_path = os.path.join(param_path, "config.json")
@@ -236,15 +241,6 @@ def train(
     if window_size is None:
         window_size = config.max_len
 
-    # Create model and load full checkpoint (state_dict + optimizer + scheduler + meta)
-    checkpoint = Checkpoint.load(param_path)
-    model = AutoRegressiveLM(config).to(dtype=torch.bfloat16)
-    model.load_state_dict(checkpoint.state_dict, strict=False)
-
-    # Strip state_dict to avoid pickling ~7GB through mp.spawn pipe
-    # (model weights already loaded into model above)
-    checkpoint.state_dict = {}
-
     strategy_kwargs = {
         "beta": dpo_beta,
         "label_smoothing": label_smoothing,
@@ -259,6 +255,7 @@ def train(
         "broadcast_buffers": False,
     }
 
+    model_fn = partial(create_model, config)
     dataset = DatasetFactory.load(
         train_type=train_type,
         load_path=data_root_path,
@@ -290,7 +287,7 @@ def train(
     )
 
     train_config = TrainConfig(
-        model=model,
+        model_fn=model_fn,
         strategy=train_type,
         dataset=dataset,
         optimizer_fn=optimizer_fn,
@@ -315,7 +312,7 @@ def train(
     )
 
     trainer = Trainer(train_config)
-    trainer.train(checkpoint=checkpoint)
+    trainer.train(resume_dir=param_path)
 
 
 if __name__ == "__main__":

tests/data/test_dataset.py

@@ -7,10 +7,8 @@ import torch
 
 from astrai.dataset.dataset import DatasetFactory, SEQDataset
 from astrai.dataset.storage import (
-    BaseSegmentFetcher,
-    H5Storage,
-    MultiSegmentFetcher,
-    StorageFactory,
+    H5Store,
+    StoreFactory,
     detect_format,
     load_json,
     save_h5,
@@ -318,37 +316,48 @@ def test_unloaded_dataset_len():
     assert len(dataset) == 0
 
 
-def test_base_segment_fetcher_empty():
-    """BaseSegmentFetcher with empty segments list"""
-    fetcher = BaseSegmentFetcher([])
-    assert len(fetcher) == 0
-    with pytest.raises(ValueError, match="out of bounds"):
-        fetcher.fetch_data(0, 1)
+def test_store_unloaded_len():
+    """Unloaded Store has __len__ == 0"""
+    store = H5Store()
+    assert len(store) == 0
+    assert store.keys == []
 
 
-def test_base_segment_fetcher_begin_equals_end(base_test_env):
-    """fetch_data with begin == end returns empty tensor"""
+def test_store_fetch_begin_equals_end(base_test_env):
+    """Store.fetch with begin == end returns empty tensor"""
     test_dir = base_test_env["test_dir"]
     dummy = {"sequence": [torch.randint(0, 1000, (100,), dtype=torch.int64)]}
     save_h5(test_dir, "empty_fetch", dummy)
 
     dataset = DatasetFactory.load("seq", test_dir, window_size=32)
-    fetcher = dataset.storage._fetcher.multi_fetchers["sequence"]
-    result = fetcher.fetch_data(10, 10)
+    result = dataset.storage.fetch(10, 10, "sequence")
     assert result.numel() == 0
 
 
-def test_multi_segment_fetcher_empty_dict():
-    """MultiSegmentFetcher with empty dict has __len__ == 0"""
-    fetcher = MultiSegmentFetcher({})
-    assert len(fetcher) == 0
+def test_store_empty_data_len(base_test_env):
+    """Store loaded with empty data has __len__ == 0"""
+    import os
+
+    test_dir = base_test_env["test_dir"]
+    data_dir = os.path.join(test_dir, "empty_store")
+    os.makedirs(data_dir, exist_ok=True)
+
+    with open(os.path.join(data_dir, "data.json"), "w") as f:
+        json.dump({"sequence": [[1, 2, 3]]}, f)
+
+    store = StoreFactory.create("json")
+    store.load(data_dir)
+    assert len(store) > 0
+
+    empty_store = H5Store()
+    assert len(empty_store) == 0
 
 
-def test_storage_fetch_before_load():
-    """BaseStorage.fetch before load raises RuntimeError"""
-    storage = H5Storage()
+def test_store_fetch_before_load():
+    """Store.fetch before load raises RuntimeError"""
+    store = H5Store()
     with pytest.raises(RuntimeError, match="not loaded"):
-        storage.fetch(0, 10, "sequence")
+        store.fetch(0, 10, "sequence")
 
 
 def test_detect_format_nonexistent_path():
@@ -367,10 +376,10 @@ def test_detect_format_unsupported_file(base_test_env):
         detect_format(path)
 
 
-def test_create_storage_invalid_type():
-    """StorageFactory.create raises ValueError for unknown type"""
+def test_create_store_invalid_type():
+    """StoreFactory.create raises ValueError for unknown type"""
     with pytest.raises(ValueError, match="Unknown component"):
-        StorageFactory.create("parquet")
+        StoreFactory.create("parquet")
 
 
 def test_json_pretokenized_without_tokenizer(base_test_env):
@@ -407,14 +416,23 @@ def test_load_json_skips_config_file(base_test_env):
     assert len(result["sequence"]) == 1
 
 
-def test_base_segment_fetcher_multi_segment():
-    """fetch_data across multiple segment boundaries"""
+def test_store_multi_segment_concat(base_test_env):
+    """Multi-segment H5 data is concatenated into single tensor at load time"""
+    import os
+
+    test_dir = base_test_env["test_dir"]
+    data_dir = os.path.join(test_dir, "multi_seg")
+    os.makedirs(data_dir, exist_ok=True)
+
     segs = [
         torch.tensor([1, 2, 3]),
         torch.tensor([4, 5, 6, 7]),
         torch.tensor([8, 9]),
     ]
-    fetcher = BaseSegmentFetcher(segs)
-    assert len(fetcher) == 9
-    result = fetcher.fetch_data(2, 7)
+    save_h5(data_dir, "data", {"sequence": segs})
+
+    store = StoreFactory.create("h5")
+    store.load(data_dir)
+    assert len(store) == 9
+    result = store.fetch(2, 7, "sequence")
     assert result.tolist() == [3, 4, 5, 6, 7]

tests/trainer/conftest.py

@@ -27,7 +27,7 @@ class TrainerDataset(Dataset):
 
 
 def create_train_config(
-    model: torch.nn.Module,
+    model_fn,
     dataset: Dataset,
     test_dir: str,
     device: str,
@@ -43,7 +43,7 @@ def create_train_config(
     """Factory function to create common TrainConfig for tests.
 
     Args:
-        model: The model to train
+        model_fn: Model factory (callable returning nn.Module)
         dataset: Training dataset
         test_dir: Checkpoint directory
         device: Device type ("cuda" or "cpu")
@@ -70,7 +70,7 @@ def create_train_config(
 
     return TrainConfig(
         strategy=strategy,
-        model=model,
+        model_fn=model_fn,
         dataset=dataset,
         optimizer_fn=optimizer_fn,
         scheduler_fn=scheduler_fn,

tests/trainer/test_callbacks.py

@@ -106,7 +106,7 @@ def test_gradient_checkpointing_trainer_integration(base_test_env, random_datase
         )
 
     train_config = TrainConfig(
-        model=base_test_env["model"],
+        model_fn=lambda: base_test_env["model"],
         strategy="seq",
         dataset=random_dataset,
         optimizer_fn=optimizer_fn,
@@ -140,7 +140,7 @@ def test_callback_integration(base_test_env, random_dataset):
         )
 
     train_config = TrainConfig(
-        model=base_test_env["model"],
+        model_fn=lambda: base_test_env["model"],
         strategy="seq",
         dataset=random_dataset,
         optimizer_fn=optimizer_fn,

tests/trainer/test_early_stopping.py

@@ -4,7 +4,6 @@ import numpy as np
 import torch
 
 from astrai.config.train_config import TrainConfig
-from astrai.serialization import Checkpoint
 from astrai.trainer.schedule import SchedulerFactory
 from astrai.trainer.trainer import Trainer
 
@@ -24,7 +23,7 @@ def test_early_stopping_simulation(base_test_env, early_stopping_dataset):
         strategy="seq",
         optimizer_fn=optimizer_fn,
         scheduler_fn=scheduler_fn,
-        model=base_test_env["model"],
+        model_fn=lambda: base_test_env["model"],
         dataset=early_stopping_dataset,
         ckpt_dir=base_test_env["test_dir"],
         log_dir=os.path.join(base_test_env["test_dir"], "logs"),
@@ -39,17 +38,20 @@ def test_early_stopping_simulation(base_test_env, early_stopping_dataset):
     trainer = Trainer(train_config)
 
     # Should handle early stopping gracefully
-    checkpoint = None
     try:
-        checkpoint = trainer.train()
+        trainer.train()
     except Exception:
-        # Handle any exceptions
         pass
 
+    # Resume from latest checkpoint
     load_dir = os.path.join(base_test_env["test_dir"], "epoch_0_iter_2")
-    checkpoint = Checkpoint.load(load_dir)
-    trainer.train(checkpoint)
+    trainer = Trainer(train_config)
+    trainer.train(resume_dir=load_dir)
 
+    # Verify checkpoint was saved at expected iteration
     load_dir = os.path.join(base_test_env["test_dir"], "epoch_1_iter_10")
-    checkpoint = Checkpoint.load(load_dir)
-    assert checkpoint.iteration == 10
+    import json
+
+    with open(os.path.join(load_dir, "meta.json")) as f:
+        meta = json.load(f)
+    assert meta["iteration"] == 10

tests/trainer/test_trainer.py

@@ -9,7 +9,7 @@ def test_different_batch_sizes(base_test_env, random_dataset, train_config_facto
 
     for batch_per_device in batch_sizes:
         train_config = train_config_factory(
-            model=base_test_env["model"],
+            model_fn=lambda: base_test_env["model"],
             dataset=random_dataset,
             test_dir=base_test_env["test_dir"],
             device=base_test_env["device"],
@@ -25,7 +25,7 @@ def test_gradient_accumulation(base_test_env, random_dataset, train_config_facto
 
     for grad_accum_steps in grad_accum_steps_list:
         train_config = train_config_factory(
-            model=base_test_env["model"],
+            model_fn=lambda: base_test_env["model"],
             dataset=random_dataset,
             test_dir=base_test_env["test_dir"],
             device=base_test_env["device"],
@@ -50,7 +50,7 @@ def test_memory_efficient_training(base_test_env, random_dataset, train_config_f
 
     for config in small_batch_configs:
         train_config = train_config_factory(
-            model=base_test_env["model"],
+            model_fn=lambda: base_test_env["model"],
             dataset=random_dataset,
             test_dir=base_test_env["test_dir"],
             device=base_test_env["device"],