Memory filling up while looping

Hey,

I have an double loop like this:


chunk <- list(1:10, 11:20, 21:30)
for(k in 1:length(chunk)){
        print(chunk[k])
        DummyCatcher <- NULL
        for(i in chunk[k]){
                print("i load something")
                dummy <- 1
                print("i do something")
                dummy <- dummy + 1
                print("i do put it together")
                DummyCatcher = rbind(DummyCatcher, dummy)
        }
        print("i save a chunk and restart with another chunk of data")
}

The problem now is that with each 'chunk'-cycle the memory used by R becomes
bigger and bigger until it exceeds my RAM but the RAM it needs for any of
the chunk-cycles alone is only a 1/5th of what I have overall.

Does somebody have an idea why this behaviour might occur? Note that all the
objects (like 'DummyCatcher') are reused every cycle so that I would assume
that the RAM used should stay about the same after the first 'chunk' cycle.


Best, Peter


SystemInfo:

R version 2.15.2 (2012-10-26)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Win7 Enterprise, 8 GB RAM