[R] Problems with lpSolve/Memory ? R crashes

[TEMPL Matthias]

Hello!

I have a curious problem, which I cannot solve.
With my code I solve thousands of small linear programs with the package lpSolve automatically.
But R crashes sometimes (~always, but always on different linear programs) in a strange way.
For illustration, I tried to prepare a simple example, which shows the nature of the problem.
The function aaa (see below) declares some constants (only in this special example) and in the end it solves the linear program.

aaa(1)
      [,1] [,2]
 [1,]    0    0
 [2,]    0    0
 [3,]    0    0
 [4,]    0    0
 [5,]   52    0
 [6,]    2    2
 [7,]    0    0
 [8,]    2    0
 [9,]    0    0
[10,]    0    0
[11,]    0    0
[12,]    0    0
[13,]   54    0

Works fine.
Now I make the *same* calculation, say 1000 times:
aaa(1000)
R (I have tried it with R2.0.1, 2.0.0, 1.9.1, 2.1.0dev) crashes completly - without warning and error message under Windows XP, Intel Pentium 3 with 256 MB RAM
Under Linux SuSe 8.2 R (2.0.1) it crashes again, but in this case I get the following message:
Calloc of 40004 bytes failed on line 114 of file lpkit.c
...
Calloc of 80008 bytes failed on line 113 of file lpkit.c
Error: cannot allocate vector of size 3 Kb

Now I´m completly lost. Solving the linear program one time makes no problem. Solving it twice in the same way makes no problem either. Running the same calculation, say 1000 times, causes a crash. Why should there be a problem with memory?

For any hint, I would be really happy. 
Thank you,
Matthias


### ---------- function aaa ------------

aaa <- function(amount=1){
f.obj <- rep(0,33)

w <- c(3,4,5,6,11,13,17,22,25,26,27,28,33)

m <- matrix(c(0,0,1,1,1,1,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

              0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,

              0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,-1,-1,-1,0,0,0,0,1,

              0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

              0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

              0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,

              0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,

              0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,

              0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,

              0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

              0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

              0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

              0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

              0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,1

              ),ncol=33,byrow=TRUE)

f.dir <- c("=","=","=","=","=","=","=","=","=","=","=",
"=","=","=","=","=","=","=","=","=","=","=","=",
"=","=","=","=","=","=","=","=","=","=")

f.rhs <- c(-52,0,54,0,2,0,0,0,0,0,0,0,0,0)

lp.out <- matrix( ncol = 2, nrow = 13 )

for(ii in 1:amount){ # - simple iterate the same

for( i in 1:13 ){

	f.obj[ w[i] ] <- 1

	lp.out[ i, 1 ] <- lp("min", f.obj, m, f.dir, f.rhs)$objval

	lp.out[ i, 2 ] <- lp("max", f.obj, m, f.dir, f.rhs)$objval

	f.obj <- rep( 0, 33 )

}

}
lp.out

}