Seems to me you're going about it in a bit of a difficult way. Assuming
you know you want to run 20 samples (x = 1 to 20), just generate sets of
20 random variables for each of your inputs.
for example,
ss <-rnorm(20,mean=.3, sd=.08)
Then inside the loop, replace "ss" with "ss[x]"
By the way, I found it a bit confusing that you used 'x' as an index.
For historical reasons, and because 'x' is the most common name for a
variable in all of math, people usually use 'i,', 'j,' 'k,' or names
beginning with those letters for indices.
Carl
<quote>
I would like to get some help from you.
Here I attach you a model, that I would like to be stochastic so I would
need each time the value of x changed, the values of parameters (ss,
emrg, gf, spp, sr) did too according to a normal distribution, with mean
its value and standard deviation given by the parameter name preceded by
SDV (In the case of parameter ss, mean is 0.3 and Standad deviation
0.08). I explain myself, the model take the mean value of these
parameter (ss, emrg, gf, spp, sr) and I would like for example, when x
changed to the value 2, the parameters values changed randomly according
to their normal distribution (given the mean and standard deviation
values) and got another mean value. And when x was 3 again, and every
time until 20. Does anyone, know how to do it?
ss <- 0.3
emrg <- 0.35
gf <- 0.22
spp <- 100
sr <- 0.52
SDVss <- 0.08
SDVemrg <- 0.05
SDVgf <- 0.04
SDVspp <- 22
SDVsr <- 0.1
data.frame <- matrix(0,20,7)
data.frame
data.frame[,1] <- 1:20
data.frame
for(x in 1:20){
if(x==1){
data.frame[1,2] <- 50
data.frame[1,3] <- 18
data.frame[1,4] <- 3
data.frame[1,5] <- 300
data.frame[1,6] <- NA
data.frame[1,7] <- NA
}else{
data.frame[x,2] <-
(data.frame[(x-1),2]-data.frame[(x-1),3]+data.frame[(x-1),5]*sr)*ss
data.frame[x,3] <- data.frame[x,2]*emrg
data.frame[x,4] <- data.frame[x,3]*gf
data.frame[x,5] <- data.frame[x,4]*spp
data.frame[x,6] <- data.frame[x,2]-
data.frame[(x-1),2]
data.frame[x,7] <- data.frame[x,2]/
data.frame[(x-1),2]
}
}
end
data.frame
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
