feat: support frozen Rain neutral predictors

1 files changed, 6 insertions, 3 deletions

diff --git a/sdil/rain_ep_adapter.py b/sdil/rain_ep_adapter.py
index bcdc410..27314bd 100644
--- a/sdil/rain_ep_adapter.py
+++ b/sdil/rain_ep_adapter.py
@@ -87,8 +87,8 @@ class RainGradientCorrector:
     ) -> None:
         if mode not in self.MODES:
             raise ValueError(f"unrecognized correction mode {mode}")
-        if neutral_cadence < 1:
-            raise ValueError("neutral cadence must be positive")
+        if neutral_cadence < 0:
+            raise ValueError("neutral cadence must be nonnegative")
         self.mode = mode
         self.predictor_rate = predictor_rate
         self.neutral_cadence = neutral_cadence
@@ -155,7 +155,10 @@ class RainGradientCorrector:
         else:
             if self.debiaser is None:
                 self._initialize_debiaser(clean)
-            if self.steps % self.neutral_cadence == 0:
+            if (
+                self.neutral_cadence > 0
+                and self.steps % self.neutral_cadence == 0
+            ):
                 self.debiaser.update_neutral(
                     bases, bias, self.predictor_rate)
             corrected = self.debiaser.residual(bases, measured)