[R] How to improve this code?

[Danny Heuman]

Hi all,

I've got some functioning code that I've literally taken hours to
write.  My 'R' coding is getting better...it used to take days :)

I know I've done a poor job of optimizing the code.  In addition, I'm
missing an important step and don't know where to put it.

So, three questions:

1)  I'd like the resulting output to be sorted on distance (ascending)
and to have the 'rank' column represent the sort order, so that rank 1
is the first customer and rank 10 is the 10th.  Where do I do this?

2)  Can someone suggest ways of 'optimizing' or improving the code?
It's the only way I'm going to learn better ways of approaching R.

3)  If there are no customers in the store's Trade Area, I'd like the
output file have nothing written to it .  How can I do that?

All help is appreciated.

Thanks,

Danny


*********************************************************
library(fields)

#Format of input files:  ID, LONGITUDE, LATITUDE

#Generate Store List
storelist <- cbind(1:100, matrix(rnorm(100, mean = -60,  sd = 3), ncol
= 1),
	     matrix(rnorm(100, mean = 50, sd = 3), ncol = 1))

#Generate Customer List
customerlist <- cbind(1:10000,matrix(rnorm(10000, mean = -60,  sd =
20), ncol = 1),
	     matrix(rnorm(10000, mean = 50, sd = 10), ncol = 1))


#Output file
outfile <- "c:\\output.txt"
outfilecolnames <- c("rank","storeid","custid","distance")
write.table(t(outfilecolnames), file = outfile, append=TRUE,
sep=",",row.names=FALSE, col.names=FALSE)

#Trade Area Size
TAsize <- c(100)

custlatlon <- customerlist[, 2:3]

for(i in 1:length(TAsize)){
	for(j in 1:nrow(storelist)){
		cat("Store: ", storelist[j],"  TA Size = ", TAsize[i],
"\n")
		
		storelatlon <- storelist[j, 2:3]
		
		whichval <-
which(rdist.earth(t(as.matrix(storelatlon)), as.matrix(custlatlon),
miles=F) <= TAsize[i])

		dist <-
as.data.frame(rdist.earth(t(as.matrix(storelatlon)),
as.matrix(custlatlon), miles=F)[whichval])

		storetag <-
as.data.frame(cbind(1:nrow(dist),storelist[j,1]))
		fincalc <-
as.data.frame(cbind(1:nrow(dist),(customerlist[whichval,1]),rdist.earth(t(as.matrix(storelatlon)),
as.matrix(custlatlon), miles=F)[whichval]))

		combinedata <- data.frame(storetag, fincalc)

		combinefinal <- subset(combinedata, select= c(-1,-3))
		
		flush.console()
	
		write.table(combinefinal, file = outfile, append=TRUE,
sep=",", col.names=FALSE)
	}
	
}