search for: numspploop

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2009 Apr 06
3
how to subsample all possible combinations of n species taken 1:n at a time?
...at about 25 taxa. The expand.grid() method: n <- 11 toto <- vector("list",n) titi <- lapply(toto,function(x) c(0,1)) tutu <- expand.grid(titi) The combn() method (a slightly lengthlier function): samplecommunityD<- function(n,numsamples) { super<-mat.or.vec(,n) for (numspploop in 1:n) { minor<-t(combn(n,numspploop)) if (dim(minor)[1]<numsamples) { minot<-mat.or.vec(dim(minor)[1],n) for (loopi in 1:dim(minor)[1]) { for (loopbi in 1:dim(minor)[2]) { minot[loopi,minor[loopi,loopbi]] <- 1 } } super<-rbind(sup...