cloudViewer::ErrorFunction Class Reference

A class to compute the Error function (erf) More...

#include <ErrorFunction.h>

Inheritance diagram for cloudViewer::ErrorFunction:

Collaboration diagram for cloudViewer::ErrorFunction:

Static Public Member Functions
static double	erfc (double x)
	Computes erfc(x) More...
static double	erf (double x)
	Computes erf(x) More...

Detailed Description

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).

Definition at line 28 of file ErrorFunction.h.

Member Function Documentation

erf()

double ErrorFunction::erf ( double  x )

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)

Parameters

x	a real variable

Returns

erf(x)

Definition at line 22 of file ErrorFunction.cpp.

References abs(), and erfc().

Referenced by cloudViewer::NormalDistribution::computeP(), cloudViewer::NormalDistribution::computePfromZero(), and define_ErrorFunction().

erfc()

double ErrorFunction::erfc ( double  x )

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).

Parameters

x	a real variable

Returns

erfc(x)

Definition at line 49 of file ErrorFunction.cpp.

References abs(), cloudViewer::c_erfRelativeError, and one_sqrtpi.

Referenced by define_ErrorFunction(), and erf().

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The documentation for this class was generated from the following files:

• /root/ACloudViewer/core/include/ErrorFunction.h
• /root/ACloudViewer/core/src/ErrorFunction.cpp