vec2lmom {lmomco}

Convert a Vector of L-moments to a L-moment Object

Description

This function converts a vector of L-moments to a L-moment object of lmomco. The object is an R list. This function is intended to facilitate the use of L-moments (and TL-moments) that the user might have from other sources. L-moments and L-moment ratios of arbitrary length are supported.

Because in typical practice, the k \ge 3 order L-moments are dimensionless ratios (\tau_3, \tau_4, and \tau_5), this function computes \lambda_3, \lambda_4, \lambda_5 from \lambda_2 from the ratios. However, typical practice is not set on the use of \lambda_2 or \tau as measure of dispersion. Therefore, this function takes an lscale optional logical (TRUE|FALSE) argument—if \lambda_2 is provided and lscale=TRUE, then \tau is computed by the function and if \tau is provided, then \lambda_2 is computed by the function.

Usage

vec2lmom(vec, lscale=TRUE,
         trim=NULL, leftrim=NULL, rightrim=NULL, checklmom=TRUE)

Arguments

vec

A vector of L-moment values in \lambda_1, \lambda_2 or \tau, \tau_3, \tau_4, and \tau_5 order.

lscale

A logical switch on the type of the second value of first argument. L-scale (\lambda_2) or LCV (\tau). Default is TRUE, the second value in the first argument is \lambda_2.

trim

Level of symmetrical trimming, which should equal NULL if asymmetrical trimming is used.

leftrim

Level of trimming of the left-tail of the sample, which will equal NULL even if trim = 1 if the trimming is symmetrical.

rightrim

Level of trimming of the right-tail of the sample, which will equal NULL even if trim = 1 if the trimming is symmetrical.

checklmom

Should the lmom be checked for validity using the are.lmom.valid function. Normally this should be left as the default unless TL-moments are being constructed in lieu of using vec2TLmom.

Value

An R list is returned.

Author(s)

W.H. Asquith

See Also

lmoms, vec2pwm

Examples

lmr <- vec2lmom(c(12,0.6,0.34,0.20,0.05),lscale=FALSE)