On Sep 16, 2007, at 10:53 AM, William Stein wrote: > On 9/16/07, David Joyner <[EMAIL PROTECTED]> wrote: >>> (0) The talk on SAGE went quite well and generated interest.
Glad to hear. >> Which basic commands (like polynomial >> multiplication) can be parallelized? [...] > So I think nontrivial parallelization at the low-level arithmetic > level is not > something that is going to happen soon, except if any third party > libraries were to do it. One exception is linear algebra, where SAGE > uses Linbox, which in turn using a system-wide optimized BLAS -- and > one can get optimized BLAS's that really do leverage multicore > machines, > e.g., this is standard on OS X. So already much of SAGE's linear > algebra > benefits from multicore machines, without us doing any work to make > that happen. > > Parallelization at a higher level, e.g., dsage, ipython1, etc., is > of course > very important and is currently being used all the time by people. It should be noted that the Python GIL puts a serious damper on parallelizing things at the python level, but as mentioned parallelizing at other levels is certainly used and valuable. If GAP can take advantage of multiple processors, it is probably a matter of setting flags when starting it up to let SAGE do this too. >> (5) How easy would it be to "certify" a computation? Suppose >> f is a function, x is input and y is output and I claim GAP (or SAGE) >> tells me that, after several days, y = f(x). I want you to believe >> me, >> so I "certify this". One way (maybe) is to have SAGE encrypt the >> start time, finish time, and printout (and maybe a pickle of some >> relevant data) into a file. This file looks random but a SAGE >> Oracle can >> verify its authenticity within a reasonable probability. > > Probably anything you could imagine doing along the above lines > could be forged. In any case, it's such a standard problem/question > that either it has been solved in other programs or systems > like Mathematica, and it's obvious what to do, or it's like DRM and > there is always a way to trick it. If somebody knows something about > this sort of question, please reply... > > Are we supposed to assume the person doing the signature is > malicious? Are do we assume the person is somewhat like me > who is -- I claim -- not malicious, and just isn't very good at > keeping > track of what they are doing, and wants a double check on what > they've computed? Then wouldn't a log be good enough? If we one wants certification, I would dump a log of the entire session (?), pickled result object, sage version information, and short description into a file and sign it with PGP. (This is assuming they have a pgp key and utility on their computer, if not I don't think it's a necessarily a good idea to try and replicate that infrastructure.) This could be automated (modulo entering a password). - Robert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
