úÎ ÀÎ NoneInverse error functions, e.g., inverf . erf = id and erf . inverf = id assuming  the appropriate codomain for . B Note that the accuracy may drop radically for extreme arguments. "Error function related functions. The derivative of  is  x -> 2 / sqrt pi * exp (x^2),  and this uniquely determines  by  erf 0 = 0. Minimal complete definition is  or .  erfc x = 1 - erf x erfcx x = exp (x*x) * erfc x normcdf x = erfc(-x  sqrt 2)  2           erf-2.0.0.0Data.Number.ErfInvErfinverfinverfc invnormcdfErferferfcerfcxnormcdfc_erfcfc_erffc_erfcc_erfinorm $fInvErfFloat$fInvErfDouble $fErfFloat $fErfDouble