# dalapl: Density and random draws from the asymmetric Laplace... In mombf: Bayesian Model Selection and Averaging for Non-Local and Local Priors

## Description

`dalapl` evaluates the probability density function, `palapl` the cumulative probability function and `ralapl` generates random draws.

## Usage

 ```1 2 3 4 5``` ```dalapl(x, th=0, scale=1, alpha=0, logscale=FALSE) palapl(x, th=0, scale=1, alpha=0) ralapl(n, th=0, scale=1, alpha=0) ```

## Arguments

 `x` Vector of values at which to evaluate the pdf/cdf `n` Number of random draws `th` Location parameter (mode) `scale` Scale parameter (proportional to variance) `alpha` Asymmetry parameter, must be between -1 and 1 `logscale` If TRUE the log-pdf is returned

## Details

For x<=th the asymmetric Laplace pdf is

0.5*exp(-abs(th-x)/(sqrt(scale)*(1+alpha)))/sqrt(scale)

and for x>th it is

0.5*exp(-abs(th-x)/(sqrt(scale)*(1-alpha)))/sqrt(scale)

## Value

`dalapl` returns the density function, `palapl` the cumulative probability, `ralapl` random draws.

David Rossell

## Examples

 ```1 2 3 4 5``` ```library(mombf) e <- ralapl(n=10^4, th=1, scale=2, alpha=0.5) thseq <- seq(min(e),max(e),length=1000) hist(e, main='', breaks=30, prob=TRUE) lines(thseq, dalapl(thseq, th=1, scale=2, alpha=0.5), col=2) ```

mombf documentation built on Dec. 6, 2019, 3:01 a.m.