# OPENGAIT RUNTIME KNOWLEDGE BASE

## OVERVIEW
`opengait/` is the runtime package: distributed launch entry, model lifecycle orchestration, data/evaluation integration.

## STRUCTURE
```text
opengait/
├── main.py         # DDP entrypoint + config load + model dispatch
├── modeling/       # BaseModel + model/backbone/loss registries
├── data/           # dataset parser + sampler/collate/transform
├── evaluation/     # benchmark-specific evaluation functions
└── utils/          # config merge, DDP passthrough, logging helpers
```

## WHERE TO LOOK
| Task | Location | Notes |
|------|----------|-------|
| Start train/test flow | `main.py` | parses `--cfgs`/`--phase`, initializes DDP |
| Resolve model name from YAML | `modeling/models/__init__.py` | class auto-registration via iter_modules |
| Build full train loop | `modeling/base_model.py` | loaders, optimizer/scheduler, ckpt, inference |
| Merge config with defaults | `utils/common.py::config_loader` | overlays onto `configs/default.yaml` |
| Shared logging | `utils/msg_manager.py` | global message manager |

## CONVENTIONS
- Imports are package-relative-at-runtime (`from modeling...`, `from data...`, `from utils...`) because `opengait/main.py` is launched as script target.
- Runtime is DDP-first; non-DDP assumptions are usually invalid.
- Losses and models are configured by names, not direct imports in `main.py`.

## ANTI-PATTERNS
- Don’t bypass `config_loader`; default config merge is expected by all modules.
- Don’t instantiate models outside registry path (`modeling/models`), or YAML `model_cfg.model` lookup breaks.
- Don’t bypass `get_ddp_module`; attribute passthrough wrapper is used for downstream method access.