Lines Matching refs:erf
41 // Coefficients for approximation to erf on [00.84375]
57 // Coefficients for approximation to erf in [0.843751.25]
187 /* double erf(double x)
191 * erf(x) = --------- | exp(-t*t)dt
195 * erfc(x) = 1-erf(x)
197 * erf(-x) = -erf(x)
202 * erf(x) = x + x*R(x^2)
203 * erfc(x) = 1 - erf(x) if x in [-.84375,0.25]
208 * | R - (erf(x)-x)/x | <= 2
212 * erf(x) = (2/sqrt(pi))*(x - x^3/3 + x^5/10 - x^7/42 + ....)
216 * point of erf(x) is near 0.6174 (i.e., erf(x)=x when x is
218 * guarantee the error is less than one ulp for erf.
222 * erf(x) = sign(x) * (c + P1(s)/Q1(s))
225 * |P1/Q1 - (erf(|x|)-c)| <= 2**-59.06
227 * erf(1+s) = erf(1) + s*Poly(s)
230 * erf(1+s) - (c = (single)0.84506291151)
238 * erf(x) = 1 - erfc(x)
247 * erf(x) = sign(x)*(1.0 - erfc(x)) if x < 6, else
248 * erf(x) = sign(x)*(1.0 - tiny)
271 * erf(x) = sign(x) *(1 - tiny) (raise inexact)
276 * erf(0) = 0, erf(inf) = 1, erf(-inf) = -1,
278 * erfc/erf(NaN) is NaN