[R] Once again in search of memory

[Eric Lecoutre]

Hello any R user,

Working on R 1.8.1 or R 1.9 on Windows, 256 Mb RAM.
I am trying to debug/correct/speedup the execution of one of our student's 
program. Basically, we perform simulations.
R is launched with high memory-limits.
One execution of the program requires nearly 200 Mbs and is OK the first 
time.  Then, launching it again does strange things: seen from Windows 
manager, the RAM used by R never exceed those 200 Mbs (often near 130Mb). 
seen from R:

 > gc(TRUE)
Garbage collection 280 = 85+59+136 (level 2) ...
396784 cons cells free (40%)
145.7 Mbytes of heap free (53%)
            used  (Mb) gc trigger  (Mb)
Ncells   587240  15.7     984024  26.3
Vcells 16866491 128.7   35969653 274.5

And then each new call to the function
foo()
will always imply a grow of this memory use (Vcells)
How comes Windows Manager states R only uses 71 Mb RAM as seen in the 
attached screenshot?
Is this a known issue? Is there any tip to "really" release memory for all 
those objects we dont use anymore?

I tried also memory.profile() which states there are more list-type 
objects. We wanipulated matrices. Could they come from calls to 'apply'?

Thansk for insights and advices on how to handle memory. I am turning and 
turning round on help pages.

Eric





Eric Lecoutre
UCL /  Institut de Statistique
Voie du Roman Pays, 20
1348 Louvain-la-Neuve
Belgium

tel: (+32)(0)10473050
lecoutre at stat.ucl.ac.be
http://www.stat.ucl.ac.be/ISpersonnel/lecoutre

If the statistics are boring, then you've got the wrong numbers. -Edward 
Tufte