CCCoreLib 31 May 2022
CloudCompare Core algorithms
|
A class to compute the Error function (erf) More...
#include <ErrorFunction.h>
Static Public Member Functions | |
static double | erfc (double x) |
Computes erfc(x) More... | |
static double | erf (double x) |
Computes erf(x) More... | |
A class to compute the Error function (erf)
See for example http://mathworld.wolfram.com/Erf.html. Most of the code comes from "erf.cpp" by Steve Strand (29-Jan-04).
|
static |
Computes erf(x)
erf(x) = 2/sqrt(pi)*integral(exp(-t^2),t,0,x) = 2/sqrt(pi)*[x - x^3/3 + x^5/5*2! - x^7/7*3! + ...] = 1-erfc(x)
x | a real variable |
|
static |
Computes erfc(x)
erfc(x) = 2/sqrt(pi)*integral(exp(-t^2),t,x,inf) = exp(-x^2)/sqrt(pi) * [1/x+ (1/2)/x+ (2/2)/x+ (3/2)/x+ (4/2)/x+ ...] = 1-erf(x) (expression inside [] is a continued fraction so '+' means add to denominator only).
x | a real variable |