erfcx_cody_middle()

double stan::math::internal::erfcx_cody_middle ( double  y )

inline

Cody (1969) second-interval rational, valid for 0.46875 <= x <= 4.

Cody writes this interval as erfc(x) = exp(-x*x) * R(x), so erfcx is R(x) with the exponential cancelled analytically: no exp and no erfc call.

Parameters

y	argument, 0.46875 <= y <= 4

Returns

scaled complementary error function

Definition at line 156 of file erfcx.hpp.