[R-es] optimización de código en R

[Carlos J. Gil Bellosta]

Hola, ¿qué tal?

Prueba esta alternativa:

sim2 <- function(nreps)  {
  nb1 <- 10  # 10 blue marbles in Urn 1
  nb2 <- 6  # 6 blue marbles orig. in Urn 2
  n1 <- 18  # number of marbles in Urn 1 at 1st pick
  n2 <- 13  # number of marbles in Urn 2 at 2nd pick
  count <- 0  # number of repetitions in which get blue from Urn 2

  nb2 <- nb2 + (runif(nreps) < nb1 / n1)
  mean( runif(nreps) < nb2 / n2  )

  #return(count/nreps)  # est. P(pick blue from Urn 2)
}

> system.time(sim1(10000))
   user  system elapsed
  0.092   0.000   0.094
> system.time(sim2(10000))
   user  system elapsed
  0.000   0.000   0.001

Un saludo,

Carlos J. Gil Bellosta
http://www.datanalytics.com



2013/1/17 Tania Patiño <taniuxpc en gmail.com>:
> Hola, me gustaria saber como óptimizar el siguiente código para que corra
> en menos tiempo de ejecución:
>
> sim1 <- function(nreps)  {
>    nb1 <- 10  # 10 blue marbles in Urn 1
>    n1 <- 18  # number of marbles in Urn 1 at 1st pick
>    n2 <- 13  # number of marbles in Urn 2 at 2nd pick
>    count <- 0  # number of repetitions in which get blue from Urn 2
>    for (i in 1:nreps)  {
>       nb2 <- 6  # 6 blue marbles orig. in Urn 2
>       # pick from Urn 1 and put in Urn 2; is it blue?
>       if (runif(1) < nb1/n1) nb2 <- nb2 + 1
>       # pick from Urn 2; is it blue?
>       if (runif(1) < nb2/n2) count <- count + 1
>    }
>    return(count/nreps)  # est. P(pick blue from Urn 2)
> }
>
>
> Gracias,
>
> Tania
>
>         [[alternative HTML version deleted]]
>
>
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