Problems with lpSolve/Memory ? R crashes

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

}