On Wed, 22 Jan 2020, 15:12 Vincent Delecroix, <[email protected]> wrote:
> Le 22/01/2020 à 15:41, Dima Pasechnik a écrit : > > On Wed, Jan 22, 2020 at 2:31 PM Vincent Delecroix > > <[email protected]> wrote: > >> > >> I had the same annoying trouble... Is it really a bug in arch? I don't > >> find anywhere where libopenblas is supposed to provide the LAPACK > >> interface. To me it is just true for SageMath and false for Archlinux. > > > > well, a "bug", in the sense that their openblas configuration just > > does not make any sense, > > because if you install a highly optimised BLAS implementation, which can > also > > provided a highly optimised CBLAS and LAPACK, in a sane world you'd > install them > > too. But Arch does not do this, it instead provides dog-slow CBLAS and > > LAPACK, built > > from another (reference, i.e. no assembler, no optimisation) > implementation. > > This causes Sage's logic, which expects that openblas will also > > provide CBLAS and LAPACK, to fail. > > > > Yes, it is possible to make tests to detect this silly setup, but I > > think that everyone's time > > is much better spent if Arch provided a full build of openblas, with > > CBLAS and LAPACK, > > instead. > > Hence there are two bugs > > * a "logical" bug in archlinux that provides a slow lapack for > (apparently) no good reason > > * a structural bug in SageMath that assumes that openblas does > install the LAPACK interface > > > I tend to agree that the resolution of any of these two would solve > the compilation. But in an ideal world we would just solve the two. > a meaningful resolution of this would be to test openblas for lapack and cblas capacities. this is relatively easy, and would result in openblas on Arch being built by Sage. as far as expanding this to other implementations of blas/lapack, it is harder. > > > >> > >> Le 13/01/2020 à 11:44, Dima Pasechnik a écrit : > >>> On Sat, Jan 11, 2020 at 11:35 AM arojas <[email protected]> wrote: > >>>> > >>>> El sábado, 11 de enero de 2020, 11:23:32 (UTC+1), Dima Pasechnik > escribió: > >>>>> > >>>>> > >>>>> > >>>>> On Sat, 11 Jan 2020, 10:19 arojas, <[email protected]> wrote: > >>>>>> > >>>>>> I suspect this may be due to our openblas package only providing > libblas.so (not libcblas.so or liblapack.so, which in our case come from > the netlib blas). > >>>>> > >>>>> > >>>>> Are you saying that your libopenblas.so does not provide everything > that is in openblas by default? > >>>>> > >>>>> This is largely defeating its purpose. > >>>>> Sage's openblas does provide the cblas and lapack capabilities. > >>>> > >>>> > >>>> In that case, openblas' spkg-configure should check whether cblas > symbols are provided by the system openblas, and if not it should compile > sage's one. It shouldn't unconditionally assume that that's always the case. > >>> > >>> I maintain that it's a bug in Arch, that libopenblas cannot be used as > >>> a replacement of cblas and lapack, for it defeats its purpose. > >>> Most uses of BLAS routines are either via LAPACK, or from C/C++, via > cblas. > >>> > >>> > >>> > >>>> > >>>> -- > >>>> You received this message because you are subscribed to the Google > Groups "sage-devel" group. > >>>> To unsubscribe from this group and stop receiving emails from it, > send an email to [email protected]. > >>>> To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/a1516e56-ab25-410e-be0f-75a7a6713466%40googlegroups.com > . > >>> > >> > >> -- > >> You received this message because you are subscribed to the Google > Groups "sage-devel" group. > >> To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected]. > >> To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/dbf38073-170b-4c7d-63b9-d4429a8794e2%40gmail.com > . > > > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/e3ad609d-8d21-bb10-2876-367fdf1b7e24%40gmail.com > . > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/CAAWYfq3p7x9KmwHLmhjOtuoy_3PdsohHN6RJ0fp0Bzxv-wHODQ%40mail.gmail.com.
