[R] Writing output to a file in a loop

[Wojtek Slusarski]

Hello,
My problem is, that I have to build hundreds of GARCH models to obtain 
volatility forecasts. I would like to run a loop, that would build those 
forecasts for me. There is no problem, with writing only the results of 
the forecasts, but I'd like to have stored results of the models in some 
file, that I could check later, what are the models like, to be able to 
compare if I should use GARCH(1,1) or GARCH(0,4) or any other, that 
suits the data best. The data file looks like that:

TICKER;DTYYYYMMDD;OPEN;HIGH;LOW;CLOSE;VOL
WIG20;19940414;1000,00;1000,00;1000,00;1000,00;71600
WIG20;19940418;1050,47;1050,47;1050,47;1050,47;99950
WIG20;19940419;1124,92;1124,92;1124,92;1124,92;138059
...
I wrote a script to do that, but when I use sink() to save the results 
in a text file, after running the script files are empty. I read in FAQ, 
that in a loop R only computes and prints only some warning messages, 
but I don't know how to do that in any other way, to ommit this problem.
Below I enclose the code:

############################################################
library(tseries)
wig20 <- read.csv("wig20.txt", sep=";", dec=",")
m <- 2321    #upper bound of time series
niter <- 10        #length(wig20$CLOSE)- m
fcv <- 0
for (i in 1:niter){
        
        m <- m + 1
        r <- 100*diff(log(wig20$CLOSE[1:m]))
        y <- r - mean(r)
        fit <- garch(y, order = c(1,1))
        sink("garch21.txt", append = TRUE)
                summary(fit)
                logLik(fit)
        sink()
        cv <- predict(fit, genuine=TRUE)
        fcv <- c(fcv,cv[length(cv)/2,1])
        postscript("garch21.ps",encoding="ISOLatin2",
                        title = paste("Day: ",wig20$DTYYYYMMDD[m]),
                        paper = "a4",
                        family = "URWTimes",
                        append = TRUE)
                
                plot(fit, ask=FALSE)
                
        dev.off()
        
}
sink("forecasts.txt")
    fcv
sink()
###################################################
The most wondering thing for me is that, plots are stored in the ps 
file, but only the ones from last iteration. In manuals there is:

append: logical; currently *disregarded*; just there for
          compatibility reasons.
What does *disregarded* actually mean and when I will be able to add a 
title before each set of plots, because now the option title is not 
adding anything to file.

I will be very thankfull for any help.
Best regards,
Wojtek Slusarski
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