This function estimates the parameters of the Rayleigh distribution given the L-moments of the data in an L-moment object such as that returned by lmoms
. The relations between distribution parameters and L-moments are
$$\alpha = \frac{2\lambda_2\sqrt{\pi}}{\sqrt{2} - 1}\mbox{,}$$
and
$$\xi = \lambda_1 - \alpha\sqrt{\pi/2}\mbox{.}$$
parray(lmom, xi=NULL, checklmom=TRUE, ...)
An R
list
is returned.
The type of distribution: ray
.
The parameters of the distribution.
The source of the parameters: “parray”.
An L-moment object created by lmoms
or vec2lmom
.
The lower limit of the distribution. If \(\xi\) is known then alternative algorithms are triggered and only the first L-moment is required for fitting.
Should the lmom
be checked for validity using the are.lmom.valid
function. Normally this should be left as the default and it is very unlikely that the L-moments will not be viable (particularly in the \(\tau_4\) and \(\tau_3\) inequality). However, for some circumstances or large simulation exercises then one might want to bypass this check.
Other arguments to pass.
W.H. Asquith
Hosking, J.R.M., 1986, The theory of probability weighted moments: Research Report RC12210, IBM Research Division, Yorkton Heights, N.Y.
lmomray
,
cdfray
, pdfray
, quaray
lmr <- lmoms(rnorm(20))
parray(lmr)
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