On Mar 23, 2010, at 11:00 PM, Hongwei Dong wrote:
Hi, please use the following the matrix z as the example:
x<-c(2,4,5,7,6,9,8,2,0)
y<-matrix(x,3,3)
z<-apply(y,2,function(x)x/sum(x))
z
[,1] [,2] [,3]
[1,] 0.1818182 0.3181818 0.8
[2,] 0.3636364 0.2727273 0.2
[3,] 0.4545455 0.4090909 0.0
require(Hmisc)
# rMultinomial expects its subject probs to be in rows rather than in
columns
# here is twenty realizations of three subjects
rMultinom(t(z), 20)
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,
13] [,14]
[1,] 3 3 2 2 1 3 3 3 3 2 2
2 2 3
[2,] 2 3 1 2 3 3 3 1 2 1 1
1 3 3
[3,] 1 1 1 2 1 1 1 1 1 1 1
1 1 1
[,15] [,16] [,17] [,18] [,19] [,20]
[1,] 3 2 3 3 3 2
[2,] 1 1 3 3 3 3
[3,] 2 1 1 1 1 1
On Tue, Mar 23, 2010 at 6:59 PM, David Winsemius <dwinsem...@comcast.net
> wrote:
On Mar 23, 2010, at 9:05 PM, Hongwei Dong wrote:
Hi, R-helpers,
I'm trying to use R to do a Monte Carlo simulation and need the
help. What I
have is a matrix that consists of the probabilities for the persons to
choose zones. For example, in the matrix shown below, each column
represents
a person, and each row represents a zone. So, the probability that
the first
person will choose the 2nd zone is 30%.
25% 30% 10% 30% 20% 0% 20% 50% 60% 50% 0% 10% 20% 0% 20%
As Alex Trebeck would say: Can you put that in the form of an R data
object?
Based on this matrix, I want to locate the persons to zones based on
the
probability using a Monte Carlo method. The result I want to see is
like
this:
0 0 0 0 0 0 0 1 1 1 0 0 0 0 0
Could anyone please give some help? Thanks.
You cannot specify what the result _will_ be and call the process
simulation of results at the same time. The sample function should
work for a vector. Why not use it?
--
David.
David Winsemius, MD
West Hartford, CT
David Winsemius, MD
West Hartford, CT
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