[Rd] maybe a bug in the system.time() function? (PR#10696)

iacob at ceremade.dauphine.fr iacob at ceremade.dauphine.fr
Mon Feb 4 16:45:04 CET 2008

Full_Name: Alessandra Iacobucci
Version: 2.5.1
OS: Mac OS X 10.4.11
Submission from: (NULL) (

I am making some intensive simulations for the testing of a Population Monte
Carlo algorithm. This involves also a study of the CPU times in two different
What I am trying to measure is the "real" CPU time, the one which is independent
on the %CPU. 

I'm using the "system.time" function with gcFirst=TRUE and I realized that all
of the output values (user, system and elapsed) depend on the percentage of the
CPU, meaning that if your program is the only one running on the machine,
system.time() gives you  certain values, and if there are many programs running
at the same time, for the exact same simulation system.time() gives you much
higher values.

Thanks for you answer.

Best regards,

Alessandra Iacobucci

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