[R] simulation data in SEM

[Don McKenzie]

What errors?  What is your output?  What output did you expect?

On Sep 14, 2014, at 6:56 AM, thanoon younis <thanoon.younis80 at gmail.com> wrote:

> Dear R members
> I want to simulate data depending on SEM and when i applied the code below
> i found some errors and i still cannot run it.
> many thanks in advance
> 
> 
> Thanoon
> 
> #Do simulation for 100 replications
> N<-1000; P<-10
> 
> phi<-matrix(data=c(1.0,0.3,0.3,1.0),ncol=2) #The covariance matrix of xi
> Ro<-matrix(data=c(7.0,2.1,2.1,7.0), ncol=2)
> yo<-matrix(data=NA,nrow=N,ncol=P) p<-numeric(P); v<-numeric(P)
> 
> for (t in 1:100) {
>    #Generate the data for the simulation study
>    for (i in 1:N) {
>        #Generate xi
>        xi<-mvrnorm(1,mu=c(0,0),phi)
>        #Generate the fixed covariates
>        co<-rnorm(1,0,1)
>        #Generate error term is structural equation
>        delta<-rnorm(1,0,sqrt(0.3))
>        #Generate eta1 according to the structural equation
>        eta<-0.8*co[i]+0.6*xi[1]+0.6*xi[2]+0.8*xi[1]*xi[2]+delta
>        #Generate error terms in measurement equations
>        eps<-rnorm(3,0,1)
> 
>        #Generate theta according to measurement equations
>        v1[1]<-1.0+eta+eps[1]; v1[2]<-1.0+0.7*eta+eps[2]
>        v1[3]<-1.0+0.7*eta+eps[3]
>        v1[4]<-1.0+xi[1]; v1[5]<-1.0+0.8*xi[1]; v1[6]<-1.0+0.8*xi[1]
>        v1[7]<-1.0+xi[2]; v1[8]<-1.0+0.7*xi[2]; v1[9]<-1.0+0.7*xi[2];
>        v1[10]<-1.0+0.7*xi1[2]
> 
> 
>        #transform theta to orinal variables
>        for (j in 1:10) { if (v[j]>0) yo[i,j]<-1 else yo[i,j]<-0 }
> 
> 
>    #Input data set for WinBUGS
>    data<-list(N=200,P=10,R=Ro,z=yo)
> 
> }   #end
> 
> 	[[alternative HTML version deleted]]
> 
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Don McKenzie
Research Ecologist
Pacific Wildland Fire Sciences Lab
US Forest Service

Affiliate Professor
School of Environmental and Forest Sciences
University of Washington
dmck at uw.edu