Le mardi 16 février 2010 à 08:40 -0600, Kumar Appaiah a écrit : > Dear Sylvestre, > > On Tue, Feb 16, 2010 at 03:35:28PM +0100, Sylvestre Ledru wrote: > > > > > > Since SVD is something I consider very important, I would request you > > > > to please re-upload Blas with an optimization level of -O2, so that > > > > things remain sane with all the reverse dependencies. > > > OK, thank for your investigation. I will do that then. > > I had a look and the problem is that blas is compiled by default with > > -03. I am afraid of switching to -02 decreases the performance on a key > > component... > > However, I have a few leads: > > * disable optimisation for just this file > > But which file? From what I can see, zgesvd in Lapack seems to > indirectly call several Blas functions. So, which file would you > compile with -O2? We would have to dig to find out...
> > * see if forcing gcc-4.3 brings back the initial behavior > > True, but this is not a permanent solution, since it is unlikely that > Squeeze will be shipped with two gcc's. Probably not. > > * report upstream (which I will probably have to do anyway) > > That is true. There is a fourth option: > > * Use -O2 on amd64, and -O3 on the rest: this is a sane option, since > Atlas is available anyway on amd64, and Atlas provides better > performance than the corresponding Blas/Lapack libraries > anyway. Would you be agreeable to this? I am not very happy about this neither. amd64 represents now a lot of computers... For the record, I just tried with Scilab and an old version of atlas and I get: 0.0288316 - 0.1225715i 0.2941664 + 0.0112984i - 0.7517416 - 0.0002798i - 0.0345902 - 0.5162818i - 0.3585172 - 0.2455863i 0.6758972 - 0.3549573i - 0.0702840 - 0.8216660i - 0.7627657 + 0.4766231i - 0.0113633 + 0.1333745i Sylvestre -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org