From help-request at octave dot org Wed Jan 19 02:45:03 2005 Subject: Re: Very slow filter.cc From: David Bateman To: akira at rsch dot tuis dot ac dot jp Cc: help at octave dot org Date: Wed, 19 Jan 2005 09:45:37 +0100 akira at rsch dot tuis dot ac dot jp wrote: >Thanks for your comment, David, > >From: David Bateman > > >>What was going to be my first step was to compile three different >>versions of octave. >>These being 2.1.50, 2.1.57 and 2.1.64, which correspond to the last >>three testing releases. The first before NDArray's were integrated, the >>second when NDArray's were integrated, but the filter function wasn't >>changed to use them and the last with the filter function converted to >>NDArray's. Getting the times of the test case you propose for these >>three build, would really confirm your problem. >> >> > >I tried octave-2.1.50 and octave-2.1.57. It took the same time as >octave-2.1.64. It means NDarray support in both filter.cc and octave >is not the slowing factor, is it right? > >Also, I carefully compared filter.cc of octave-2.1.50 and >octave-2.0.17. It seems there is no difference in filtering algorithm >itself. I realized that the slow filter.cc comes from more essential >part of octave-2.1.x. > > Hi Akira, Then this indeed means that the NDArray support is not the cause of the problem. This might point to a deeper problem, but it is difficult to see what. It might also just be a problem with the time measurement under 2.0.17, or on your machine. Did you do a sanity check on the numbers? You measured 14.7 and 1.62 seconds. Are these the wall-times that these really took? you might also try t = cputime; y = filter(b,1,x); cputime - t rather than using tic/toc and see if there is better consistency between 2.0.17 and the 2.1.x versions... If the problem remains, the next step woul dbe to profile the two versions of octave to figure out what is taking the time. Though that is likely to take a lot of effort... Regards David -- David Bateman David dot Bateman at motorola dot com Motorola CRM +33 1 69 35 48 04 (Ph) Parc Les Algorithmes, Commune de St Aubin +33 1 69 35 77 01 (Fax) 91193 Gif-Sur-Yvette FRANCE The information contained in this communication has been classified as: [x] General Business Information [ ] Motorola Internal Use Only [ ] Motorola Confidential Proprietary ------------------------------------------------------------- Octave is freely available under the terms of the GNU GPL. Octave's home on the web: http://www.octave.org How to fund new projects: http://www.octave.org/funding.html Subscription information: http://www.octave.org/archive.html -------------------------------------------------------------