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dzeroc Zero Cumulant Distribution
DESCRIPTION
Density of the Zero Cumulant Distribution of order 6. The first six cumulants are specified, and the others are assumed zero.
 
USAGE
dzeroc(x,kappa)
 
REQUIRED ARGUMENTS
x vector of quantiles.
kappa vector of length 6 holding the cumulants of the distribution.
 
VALUE
Vector of same length as x giving the density of the distribution with cumulants given by kappa.
 
DETAILS
Uses 400-point Gaussian quadrature to invert the moment generating function.
 
REFERENCE
Smyth, G. K. (1993). Zero cumulant distribitions. Unpublished manuscript.
 
EXAMPLES
The normal distribution is determined exactly by its first two cumulants:
> dzeroc(x=c(0,1,2,3),kappa=c(0,1,0,0,0,0))
[1] 0.398942280 0.241970725 0.053990967 0.004431848
> dnorm(x=c(0,1,2,3))
[1] 0.398942280 0.241970725 0.053990967 0.004431848
 
The gamma distribution can be approximated by its first 6 cumulants:
> dzeroc(x=5,kappa=rep(5,6))
[1] 0.1754872
> dgamma(x=5,shape=5)
[1] 0.1754674

 

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Gordon Smyth. Copyright © 1996-2016. Last modified: 10 February 2004