#mplusfile: name of mplus file without extension.
#number.results: number of parameters + standard errors + fit info reported by MPLUS
#conditions: vector of descriptors of conditions being manipulated
run_sem=function(mplusfile,number.results,conditions) {

 #Run Mplus.
inputfile <- paste(mplusfile,".inp",sep="")
system(paste("mplus.exe",inputfile,sep=" "), wait = TRUE, show.output.on.console = F)

#scan all results.
results <- scan(file="results.txt")

#organize the data into a table.
results <- matrix(results,,number.results, byrow = T)

#obtain the number of iterations that converged
number.converged <- nrow(results)

#organize results.
condition.descriptors <- matrix(conditions,dim(results)[1],length(conditions),byrow=T)
results <- data.frame(condition.descriptors,results)

#save results
write.table(results, file = "all_results.csv",sep=",", row.names = F,col.names = F, append = T)

} #close function.