# rexptr: Random generator for a Truncated Exponential distribution. In RGeode: Geometric Density Estimation

## Description

Simulate random number from a truncated Exponential distribution.

## Usage

 `1` ```rexptr(n = 1, lambda = 1, range = NULL) ```

## Arguments

 `n` int, optional number of simulations. `lambda` double, optional parameter of the distribution. `range` array_like, optional domain of the distribution, where we truncate our Exponential. range(0) is the min of the range and range(1) is the max of the range.

## Details

It provide a way to simulate from a truncated Exponential distribution with given pameter λ and the range range. This will be used during the posterior sampling in th Gibbs sampler.

## Value

`rexptr` returns the simulated value of the distribution:

 `u` double it is the simulated value of the truncated Exponential distribution. It will be a value in (range(0), range(1)).

## Author(s)

L. Rimella, lorenzo.rimella@hotmail.it

## References

• [1] Y. Wang, A. Canale, D. Dunson. "Scalable Geometric Density Estimation" (2016).
The implementation of rgammatr is inspired to the Matlab implementation of rexptrunc by Ye Wang.

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23``` ```#Simulate a truncated Exponential with parameters 0.5 in the range #5,Inf. #Set the range: range<- c(1,Inf) #Simulate the truncated Gamma set.seed(123) vars1<-rexptr(1000,0.5,range) #Look at the histogram hist(vars1,freq=FALSE,ylim=c(0,2),xlim = c(0,5)) lines(density(vars1)) #Compare with a non truncated Exponential set.seed(123) vars2<-rexp(1000,0.5) #Compare the two results lines(density(vars2),col='red') #Observation: simulate without range is equivalent to simulate from #rexp(1000,0.5) ```

RGeode documentation built on May 2, 2019, 1:09 p.m.