tenseleyflow/sway / 4cde232

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sway(core): ScalableDifferentialBackend protocol for adapter-scale access

Authored by espadonne
SHA
4cde23284d23c934fbfd04ba8b1ec62873b5badc
Parents
cc8e52f
Tree
28e9323

2 changed files

StatusFile+-
M src/dlm_sway/__init__.py 2 0
M src/dlm_sway/core/scoring.py 21 0
src/dlm_sway/__init__.pymodified
@@ -13,6 +13,7 @@ from dlm_sway.core.result import ProbeResult, SuiteResult, SwayScore, Verdict
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 from dlm_sway.core.scoring import (
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     DifferentialBackend,
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     RollingLogprob,
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+    ScalableDifferentialBackend,
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     ScoringBackend,
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     TokenDist,
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 )
@@ -26,6 +27,7 @@ __all__ = [
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     "ProbeError",
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     "ProbeResult",
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     "RollingLogprob",
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+    "ScalableDifferentialBackend",
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     "ScoringBackend",
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     "SpecValidationError",
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     "SuiteResult",
src/dlm_sway/core/scoring.pymodified
@@ -140,6 +140,27 @@ class DifferentialBackend(Protocol):
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     def as_finetuned(self) -> AbstractContextManager[_ScoringModel]: ...
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+@runtime_checkable
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+class ScalableDifferentialBackend(DifferentialBackend, Protocol):
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+    """A differential backend that can also scale the LoRA additive term.
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+
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+    LoRA applies ``W + (alpha/r) · B @ A`` to a base weight matrix. This
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+    protocol exposes a context manager that temporarily multiplies that
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+    additive term by ``lam`` for everything inside the ``with`` block.
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+
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+    ``lam = 0.0`` is equivalent to :meth:`as_base`.
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+    ``lam = 1.0`` is equivalent to :meth:`as_finetuned`.
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+    ``lam = 1.25`` overshoots — useful for N2 AdapterAblation's
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+    response-curve measurement.
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+
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+    Only the HF backend ships an implementation in v0.1. Probes that
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+    need scaling check via ``isinstance(backend, ScalableDifferentialBackend)``
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+    at runtime and SKIP gracefully when unavailable.
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+    """
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+
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+    def as_scaled_adapter(self, lam: float) -> AbstractContextManager[_ScoringModel]: ...
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+
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+
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 # Helper Protocol for type-checking the yielded context object: it
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 # must satisfy both Model and ScoringBackend. mypy doesn't support
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 # intersection types, so we spell it out explicitly.