Difference between revisions of "GammaI"
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== Library == | == Library == | ||
Advanced Math, [[Distribution Densities Library]] ([[media:Distribution Densities.ana|Distribution Densities.ana]]) | Advanced Math, [[Distribution Densities Library]] ([[media:Distribution Densities.ana|Distribution Densities.ana]]) | ||
− | :Use | + | :Use [[File menu|File]] → '''Add Library...''' to add this library |
== See Also == | == See Also == |
Latest revision as of 21:16, 24 May 2016
GammaI(x, a, b)
Returns the incomplete gamma function, defined as:
- [math]\displaystyle{ GammaI(x,a,b) = {1\over{\gamma(a)}} \int_0^{x/b} e^{-t} t^{a-1} dt }[/math]
«a» is the shape parameter, «b» is an optional scale factor (default b = 1). Note that some textbooks use [math]\displaystyle{ \lambda = 1/a }[/math] as the scale factor. The incomplete gamma function is defined for x ≥ 0.
The incomplete gamma function returns the cumulative area from zero to «x»' under the Gamma distribution.
The incomplete gamma function is useful in a number of mathematical and statistical contexts.
Library
Advanced Math, Distribution Densities Library (Distribution Densities.ana)
- Use File → Add Library... to add this library
See Also
- GammaFn -- the complete gamma function
- LGamma
- Gamma -- the gamma distribution
- GammaIInv -- the inverse of GammaI
- BetaI -- the incomplete beta function
- Distribution Densities Library
- Distribution Densities.ana
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