[Numpy-discussion] extracting a random subset of a vector

Curzio Basso curzio.basso at unibas.ch
Wed Sep 8 02:11:05 CDT 2004


Robert Kern wrote:

 >>>> a question about the method: isn't a bit risky to use the clock() 
for timing the performance? The usual argument is that CPU allocates 
time for different processes, and the allocation could vary.
 >>>
 >>>
 >>> that's why I use time.clock() rather than time.time().
 >>
 >>
 >>   Perhaps clearing up a mutually divergent assumption:  time.clock() 
measures CPU time on POSIX and wallclock time (with higher precision 
than time.time()) on Win32.
 >
 >
 > FWIW, the idiom recommended by Tim Peters is the following:
 >
 > import time
 > import sys
 >
 > if sys.platform == 'win32':
 >     now = time.clock
 > else:
 >     now = time.time
 >
 > and then using now() to get the current time.


Ok, now I'm really confused...

 From the doc of the module 'time': the clock function "return the 
current processor time as a floating point number expressed in seconds." 
AFAIK, the processor time is not the time spent in the process calling 
the function. Or is it? Anyway, "this is the function to use for 
benchmarkingPython or timing algorithms.", that is, if processor time is 
good enough, than use time.clock() and not time.time(), irregardless of 
the system, right?




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