[R] Fwd: Simulate nested data

[Sarah Goslee]

Andrea,

I don't understand what you want. Why don't you start over, and
explain what the inputs are, and what your desired outputs are.

Using your previous code:

# pre-specified number of groups
groups <- 3
# what is species? It needs to be defined before
# we can assign a value to a component of it
species <- ???

# randomly assign between 1 and 10
# species per functional group for each group
# specified in the groups variable
species$groups<-as.integer(runif(groups,1,10))

# original code to set up p
# I assumed this was supposed to create an
# array of groups dimension, but apparently
# that isn't true
p<-array(NA,dim=c(species$groups))

# you wrote:
# > I need to have a single value of p per species, and the total number of
# > elements in p would be whatever number results from
# > species(group1)+species(group2)+species(group3)
# which suggests to me that you do not need an array at all, but
# simply a vector of the length of the number of species:
p <- rep(NA, sum(species$groups))

# but that isn't clear to me because I'm not sure what you
# mean by species(group1), since there is no species()
# function defined




On Fri, Nov 9, 2012 at 2:49 PM, Andrea Goijman
<agoijman at cnia.inta.gov.ar> wrote:
> Yes, I tried your suggestion, but it didn't help. It just creates a
> tri-dimentional array for p... and that is not what I want p per species
> (within groups) to be an unbalanced array...
>
> I need to have a single value of p per species, and the total number of
> elements in p would be whatever number results from
> species(group1)+species(group2)+species(group3)
>
>
>
>
> On Fri, Nov 9, 2012 at 2:40 PM, Sarah Goslee <sarah.goslee at gmail.com> wrote:
>>
>> Andrea,
>>
>> I simply meant that I couldn't run your code assigning a value to
>> species$groups
>> because the code didn't include any information about creating the R
>> object species. Thus, I changed the name of that R object to
>> speciesgroups and altered your code so that it runs by removing the
>> erroneous c().
>>
>> Did you try my suggestion, and did or did it not help your problem?
>>
>> Sarah
>>
>> On Fri, Nov 9, 2012 at 2:37 PM, Andrea Goijman
>> <agoijman at cnia.inta.gov.ar> wrote:
>> > Hi Sarah,
>> >
>> > Maybe I expressed myself wrong, but so far, I don't have the species;
>> > I'm
>> > just wanting to generate simulated data. For example, creating an
>> > unbalanced
>> > (and random) number of species per group, and then run the for-loops
>> >
>> > for example:
>> > Group1: 3 species
>> > Group2: 5 species
>> > Group3: 8 species
>> >
>> > then, I want to create an array "p" to be able to fill the following
>> > loop
>> >
>> > for (g in 1:groups){
>> >            for (i in 1:species[g]){
>> >                p[i] <- rnorm(1, mu.p[g], tau.p[g])
>> >      }#species
>> > }
>> >
>> >
>> > Andrea
>> >
>> >
>> >
>> >
>> > On Fri, Nov 9, 2012 at 2:26 PM, Sarah Goslee <sarah.goslee at gmail.com>
>> > wrote:
>> >>
>> >> Hi Andrea,
>> >>
>> >> Without knowing what species is, I can't run your code as is, but try
>> >> this:
>> >>
>> >>
>> >> groups<-3
>> >> speciesgroups <- as.integer(runif(groups,1,10))
>> >> # I'd use sample(1:10, groups, replace=TRUE)
>> >> p<-array(NA,dim=speciesgroups)
>> >>
>> >>
>> >> Mostly you're trying to use c() on something that's already a vector.
>> >>
>> >> Sarah
>> >>
>> >> On Fri, Nov 9, 2012 at 2:16 PM, Andrea Goijman
>> >> <agoijman at cnia.inta.gov.ar> wrote:
>> >> > I know this seems like a very easy question (and maye it is) but I've
>> >> > been
>> >> > trying to simulate nested data and been unsucessful so far..
>> >> >
>> >> > I want to simulate a varying number of species within a group; and
>> >> > then
>> >> > create an array to store the results of my for-loop. For example:
>> >> >
>> >> > groups<-3
>> >> > species$groups<-as.integer(runif(groups,1,10))  #species per
>> >> > functional
>> >> > group
>> >> >
>> >> > ###create arrays to store results
>> >> >
>> >> > p<-array(NA,dim=c(species$groups))
>> >> >
>> >> > So, far this is not working...
>> >> >
>> >> > Thanks!
>> >>
>> >>


--
Sarah Goslee
http://www.functionaldiversity.org