A trip to the Spatial Task View on CRAN might be in order. The RandomFields
package comes to mind.
-Don
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
Lab cell 925-724-7509
On 11/9/17, 12:37 AM, "R-help on behalf of PIKAL Petr"
<r-help-boun...@r-project.org on behalf of petr.pi...@precheza.cz> wrote:
Hi
it smells like a homework, this list has no homework policy.
Anyway, maybe the sample approach could be used.
Generate x,y coordinates - ?expand.grid
sample n centers - ?sample
select all points within defined area - ?point.in.polygon, package sp
select desired number of points - ?sample
Cheers
Petr
> -----Original Message-----
> From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of john
lukore
> Sent: Thursday, November 9, 2017 4:40 AM
> To: r-help@r-project.org
> Subject: [R] R-help
>
> Generate a clustered pattern in [0; 1]2 as follows:
>
> (a) Generate nc, say 20, independent cluster centres (which can be called
> parents) that are distributed i.i.d. uniformly in the unit square;
>
> (b) then n daughters are assigned i.i.d. uniformly to these parents and
such
> that each daughter is located i.i.d. uniformly in a disk of radius r =
> 0:1 centred at her parent, under the periodic boundary conditions (i.e.
the
> square = a torus).
>
>
> My attempt so far is:
>
>
> set.seed(1) library(spatstat)
>
> n_parent <- 2
>
> n_daughter <- 4
>
> r = 0.1
>
> cnt <- n
>
> W <- disc(radius=3, centre=c(0,0)) i <- 1
>
> while(i <= n_daughter){
>
> d_x <- runif(1)
>
> d_y <- runif(1)
>
> if (d_x ^2+d_y^2 <r) {
>
> i = i+1}}
>
>
> #need a condition here such that (d_x,d_y) lies in B(0,r)
>
> #where B(0,r) is a ball of center origin and of radius r
>
> In above we should obtain one ball with n_daughters. Next step is to
generate
> parent centers and distribute the n_daughters in the ball into n_parents.
>
> [[alternative HTML version deleted]]
>
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