# [R] LHS random number generator

Jim Lemon drj|m|emon @end|ng |rom gm@||@com
Tue Apr 13 09:02:10 CEST 2021

```Hi Shah,
I think what you are struggling toward is this:

prior_lhs <- list(r_mu=c( 0.00299, 0.0032),
r_sd=c( 0.001, 0.002),
lmp=c( 0.40, 0.43),
gr_mu=c( 0.14, 0.16),
gr_s=c( 0.01, 0.020),
alpha1=c( 0.0001, 0.0018),
alpha2=c(0.0017, 0.0028),
alpha3=c( 0.005, 0.009),
beta=c(0.69, 0.75))
for(i in 1:length(prior_lhs))
prior_lhs[[i]]<-seq(prior_lhs[[i]][1],prior_lhs[[i]][2],length.out=4)

This gives you the "quartiles" you need for randomLHS function in the
"lhs" package if I read the help page correctly.

Jim

On Mon, Apr 12, 2021 at 10:21 PM Shah Alam <dr.alamsolangi using gmail.com> wrote:
>
> Hello everyone,
>
> I am using the LHS package to generate a combination of a
> set of parameter values. However, I am not sure how to fix some parameter
> values to 2 decimal points.
> For example:
>
> I want to make combinations in such a way that values for parameter
> c("lmp", 0.40, 0.43) are taken as 0.40, 0.41, 0.42,0.43.
>
> My codes are:
>
> prior_lhs <- list(c("r_mu", 0.00299, 0.0032),
>                   c("r_sd", 0.001, 0.002),
>                   c("lmp", 0.40, 0.43),
>                   c("gr_mu", 0.14, 0.16),
>                   c("gr_sd", 0.01, 0.020),
>                   c("alpha1", 0.0001, 0.0018),
>                   c("alpha2", 0.0017, 0.0028),
>                   c("alpha3", 0.005, 0.009),
>                   c("beta", 0.69, 0.75)
> )
>
>
> ### Simulation with priors from LHS ####
> nb_simul <- 10000
> nparam <- length(prior_lhs)
> random_tab = randomLHS(nb_simul, nparam)
> lhs_index = 1
> param <- matrix(rep(0, nparam), nrow = 1, ncol = nparam)
>
> for (i in 1:nb_simul) {
>   temp_par <- matrix(rep(0, nparam), nrow = 1, ncol = nparam)
>   for (j in 1:nparam) {
>     temp_par[j] = as.numeric(prior_lhs[[j]][2]) +
>       (as.numeric(prior_lhs[[j]][3]) - as.numeric(prior_lhs[[j]][2])) *
> random_tab[lhs_index, j]
>   }
>   param <- rbind(param, temp_par)
>   lhs_index <- lhs_index+1
> }
> param <- param[-1,]
>
> Best regards,
> Shah
>
>         [[alternative HTML version deleted]]
>
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