Double ErfcInv(Double y)
Inverse complementary error function.
| # | Name | Type | Description |
|---|---|---|---|
| 1 | y | Double | scalar |
Returns: Double - x such that Erfc(x) equals y, for 0 < y < 2.
Remarks:
Shares the ALGORITHM AS241 (PPND16) rationals with Dew.Math.Units.Math387.ErfInv but takes the complementary probability, which keeps both tails exact: y/2 is a power-of-two scaling and 1-y/2 is exact by Sterbenz, so no information is lost at either end. ErfInv(1-y) would instead cap the small-y tail at an absolute 5.55E-17. Returns +MAXNUM at y=0 and -MAXNUM at y=2; raises outside 0..2.
See Also: Math387.ErfInv, Math387.Erfc