From maintainers-request at octave dot org Sun Jan 30 02:07:44 2005
Subject: Re: min function very slow?
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: "Dmitri A. Sergatskov" <dmitri at unm dot edu>
Cc: Daniel J Sebald <daniel dot sebald at ieee dot org>, maintainers@octave.org
Date: Sun, 30 Jan 2005 02:06:22 -0600

On 30-Jan-2005, Dmitri A. Sergatskov <dmitri at unm dot edu> wrote:

| Though ignore_function_time_stamp = "all", I still get mintime consistently
| longer then maxtime:
| 
| octave:2> [looptime,maxtime,mintime]=mmt(10000)
| looptime = 0.046946
| maxtime = 0.19471
| mintime = 0.22528
| octave:3> [looptime,maxtime,mintime]=mmt(10000)
| looptime = 0.040380
| maxtime = 0.18160
| mintime = 22.642
| octave:4> ignore_function_time_stamp = "all"
| ignore_function_time_stamp = all
| octave:5> [looptime,maxtime,mintime]=mmt(10000)
| looptime = 0.040041
| maxtime = 0.17199
| mintime = 0.21179
| ...
| octave:8> [looptime,maxtime,mintime]=mmt(30000)
| looptime = 0.10826
| maxtime = 0.51337
| mintime = 0.61531
| octave:9> [looptime,maxtime,mintime]=mmt(300000)
| looptime = 0.97805
| maxtime = 5.1094
| mintime = 6.0628

With ignore_fucntion_time_stamp = "all", you tell it to not check to
see if the function is out of date.  But there could still be some
significant overhead to look it up the first time.  It is odd that
searching for a function would take more time when it can be found in
a shared library that is already loaded, but that seems to be what is
happening.  In any case, I don't think this has anything to do with
min or max since you can get similar results with other functions that
are defined from the same .oct file.  Also, try switching the order of
the calls to min and max in your script and run it again in a freshly
started Octave session and you should see that the second function
loaded is the slower one.

jwe