Fix calculation of gap thresholds #408
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…ratio computations In the calculation of `gapLow[y]` and `gapHigh[y]`, the expressions for the ratio-based thresholds were incorrectly using `Math.abs(a)` where `a = scale[y] * point[startPosition + y]`. Since `point[startPosition + y]` is the normalized value `(x - mean) / std`, multiplying by `scale[y]` (which is `std`) gives `(x - mean)`. However, to accurately compute the thresholds based on the actual value `x`, we need to add back the mean (`shiftBase`). Therefore, `(a + shiftBase)` equals `(x - mean) + mean = x`. The corrected code now uses `Math.abs(a + shiftBase)` in PredictorCorrector. Testing done: 1. added a IT. Signed-off-by: Kaituo Li <[email protected]>
greaa-aws
approved these changes
Oct 10, 2024
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Issue #, if available:
Description of changes:
In the calculation of
gapLow[y]andgapHigh[y], the expressions for the ratio-based thresholds were incorrectly usingMath.abs(a)wherea = scale[y] * point[startPosition + y]. Sincepoint[startPosition + y]is the normalized value(x - mean) / std, multiplying byscale[y](which isstd) gives(x - mean).However, to accurately compute the thresholds based on the actual value
x, we need to add back the mean (shiftBase). Therefore,(a + shiftBase)equals(x - mean) + mean = x.The corrected code now uses
Math.abs(a + shiftBase). Read changes in PredictorCorrector for details.Testing done:
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