Re: split a list
- To: mathgroup at smc.vnet.net
- Subject: [mg40669] Re: split a list
- From: Bill Rowe <listuser at earthlink.net>
- Date: Sat, 12 Apr 2003 03:13:39 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On 4/11/03 at 11:20 AM, Hartmut.Wolf at t-systems.com (Wolf, Hartmut) wrote: >>-----Original Message----- From: Bill Rowe To: mathgroup at smc.vnet.net >>[mailto:listuser at earthlink.net] Sent: Friday, April 11, 2003 8:06 AM >>To: mathgroup at smc.vnet.net Subject: [mg40669] [mg40639] Re: split a list >>Yes, my enviroment is different (MacOS X, 1024MB Ram, 800 MHz G4, >>Mathematica 4.2.1). With a different environment it isn't surprising >>the actual times are different. But I would have thought the time >>rankings would be the same given the same version of Mathematica. It >>seems interesting this doesn't seem to be the case. Clearly a case of >>user beware. >this is not a surprising phenomenon. As the total computation time is >not the result of a single hardware parameter (say CPU clock), but >involves quite a row: instruction set, CPU architecture, management of >the instruction pipeline, caching hierachy, strategy and cache access >times and finally core memory access. (You may possibly change some >paramters with BIOS set-up.) Also, quite often, machine code is >optimized in different ways for different machine architectures. You make very good points. So, it would seem the only conclusions that can be drawn from timing tests done in a different environment are code that runs significantly faster is likely to be faster on a different environment with the same version of Mathematica If there is only a small difference (10-20%) there is likely to be only a small difference in a different environment and there is no guarantee the code that is faster will continue to be faster.