R has some strange behavior in its memory management. (R-0.62.2 and R-0.63.0 of July 22) If I start R on a PC with 256MB with the option -v 200, and want to see the free memory I get R> gc() Garbage collection ... 111801 cons cells free (55%) 204554k bytes of heap free (-63%) So, I have suddenly a negative percentage of memory free. This value becomes not positive, unless a certain amount of memory is used. R> x <- matrix(0,1000,1000) R> gc() Garbage collection ... 111797 cons cells free (55%) 196741k bytes of heap free (-67%) R> x <- matrix(0,4000,1000) R> gc() Garbage collection ... 111797 cons cells free (55%) 173304k bytes of heap free (-79%) R> x <- matrix(0,5000,1000) R> gc() Garbage collection ... 111797 cons cells free (55%) 165491k bytes of heap free (80%) The second point I came across is the following. R is now started with -v 100 -n 1000000. After R> x <- matrix(0,5000,900) I have still enough memory free. R> gc() Garbage collection ... 911797 cons cells free (91%) 66997k bytes of heap free (65%) So, if x uses 35% of heap memory, there should still be enough memory for a second matrix of this size, but the command R> y <- matrix(0,5000,900) runs out of heap memory. Similarly, I can create a 5000x1300-matrix on a newly started R with -v 100 and have still 50% heap memory free, but I can not create a 5000x1400-matrix, if R is started with -v 100. So, I suppose that R needs a complete copy of this matrix while creating it and therefore I can only create matrices which use less than half of the free memory. Is there any way to avoid this memory usage? ************************************************************************ * Andreas Weingessel * ************************************************************************ * Institut f=FCr Statistik * Tel: (+43 1) 58801 4541 * * Technische Universit=E4t Wien * Fax: (+43 1) 504 14 98 * * Wiedner Hauptstr. 8-10/1071 * Andreas.Weingessel@ci.tuwien.ac.at * * A-1040 Wien, Austria * http://www.ci.tuwien.ac.at/~weingessel * ************************************************************************ -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._