# GPU Feature Parity Contract V1

Status: `accepted`.

The contract requires exact structure and NaN placement, exact decision/state-transition conditions, and per-family measured numeric limits. Numeric drift is never accepted when it changes a decision.

## Family Limits

- `bollinger`: max abs 1.8262653611600399e-09, max rel 2.9899920253705082e-14, max ULP 251, MAE 6.4296249767118589e-10.
- `supertrend`: max abs 0, max rel 0, max ULP 0, MAE 0.
- `donchian`: max abs 0, max rel 0, max ULP 0, MAE 0.
- `keltner`: max abs 2.9103830456733704e-11, max rel 4.2852960505130111e-16, max ULP 2, MAE 9.9198121522888284e-16.
- `psar`: max abs 0, max rel 0, max ULP 0, MAE 0.

## Gates

- Shapes, dtypes, and NaN masks must match exactly.
- Price-comparison signs, crossings above/below, and state-transition conditions must match exactly.
- Bollinger and Keltner upper/lower relationships must match exactly.