Dear List,

 

For what I understand, strptime() simply converts from one class
representation to another; i.e., from character to POSIXct/POSIXlt.

 

One strange feature of this command running on Linux is that there are
repeated calls to system time (as was revealed in a trace of system
calls), which considerably affect performance.  These system calls end
up taking almost 75% of the execution time, and are completely
unnecessary.

 

Code:

ptm <- proc.time()

for (i in 1:100000) strptime("2010-03-10 17:00:00", "%F %H:%M:%S")

(proc.time() -ptm)

 

Output on Windows Box (32-bit R 2.9.1 running on Intel X5472 @ 3.0 GHz):

   user  system elapsed 

   1.31    0.02    1.30

 

Output on Linux Box (64-bit R 2.10.1 running on Intel Xeon E5520 @
2.27GHz):

   user  system elapsed 

   3.33    8.941    12.273

 

Any help would be appreciated.  Also, if I should turn to a different
mailing list for this, please let me know.

 

Regards,

Alex  


	[[alternative HTML version deleted]]

