Hello there!
Remmy is my name and I came across an interesting code in R on this web
https://stat.ethz.ch/pipermail/r-help/2004-May/050424.html , there are some
parts that I have not followed and I would like to get some comments if you may!
Please comment on the highlighted two parts of the code below in color blue!
I create a rotine for a problem like this, I hope this is useful for you
------------
#############################################
## MARKOV CHAIN ##
## ##
## ini- initial state ##
## trans- transition matrix ##
## n - number of transitions ##
## f - ini%*%trans ##
## fase - f consolidate ##
## ##
#############################################
# initial state
ini<-matrix(c(10,0,0,0,0,0,0,0,0),nrow=3,ncol=3)
# transition matrix
#
# [,1] [,2] [,3]
# [1,] 0.85 0.1 0.05
# [2,] 0.00 0.7 0.3
# [3,] 0.00 0.0 1.0
#
# In R the command is
trans<-matrix(c(.85,0,0,.1,.7,0,0.05,0.3,1),ncol=3)
markov<-function(ini,trans,n){
l<-ncol(ini)
fase<-matrix(0,nrow=l,ncol=l)
fases<-array(0,dim=c(nrow(ini),ncol(ini),n))
for (i in 1:n){
f<-ini%*%trans
for (w in 1:l){fase[w,w]<-sum(f[,w])}
ini<-fase
fases[,,i]<-fase
# print(fase)
#
# Fase allow calcule de value for transition:
# If sate 1 value 0,95, state 2 value 0,3 and state 3
# value 0 QALY.
# I´m calculate de value of any transition if
# print(sum(fase%*%c(.95,.3,0)))
#
#
}
return(fases)
}
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