All, Then there is also John Gustafson's <http://www.johngustafson.net/bio/current-resume.pdf> Unums & Posits, which are specifically designed to extend the floating-point range on binary computers: The End of (Numeric) Error - John L. Gustafson <https://ubiquity.acm.org/article.cfm?id=2913029> The Unum Number Format (Wikipedia) <https://en.wikipedia.org/wiki/Unum_(number_format)> Beyond Floating Point: Next-Generation Computer Arithmetic <https://web.stanford.edu/class/ee380/Abstracts/170201.html> Beyond Floating Point - Slides <https://web.stanford.edu/class/ee380/Abstracts/170201-slides.pdf>
Skip Cave Cave Consulting LLC On Wed, Feb 3, 2021 at 2:22 PM Henry Rich <[email protected]> wrote: > The multiplication algorithm is brute-force. FFT methods are orders of > magnitude faster for large numbers. > > Numbers are actually stored in base 10000 IIRC. > > Extended arithmetic is not a mainstream use, but if we support it we > might as well do it as well as we can. > > Henry Rich > > On 2/3/2021 3:05 PM, 'Pascal Jasmin' via Programming wrote: > > The core performance bottleneck with extended precision numbers in J is > that they are stored in base 10. That decision does come with a > performance advantage of its own: input and display. I'd favour the move > to 32/64 bit storage even if it "broke" the 3!:1 format (although 3!:1 > could convert to old storage style). J is already shipping with openssl > that has large integer operations. Is there that big a case to add GMP as > a dependency? > > > > > > > > > > > > > > On Wednesday, February 3, 2021, 09:47:51 a.m. EST, Henry Rich < > [email protected]> wrote: > > > > > > > > > > > > IF you want to get yourself in shape to make JE changes, I have a > > starter project for you: replace the extended-integer and rational > > support with GMP (or some other equally-good library). The current code > > is serviceable but sized for 32-bit machines, and lacks fast > multiplication. > > > > The code resides in vx.c and vq.c, which would be replaced with new > > versions. There are also bits in k.c (conversions) and d.c (display). > > > > I will help as needed. > > > > Henry Rich > > > > On 2/1/2021 11:25 PM, ethiejiesa via Programming wrote: > >> Raul Miller <[email protected]> wrote: > >>> https://github.com/jsoftware/jsource/commits/master might interest > you... > >> Indeed, I have the repo cloned locally! > >> > >> However, when digging through old bug reports, I find it quite > challenging to > >> match up the "fixed" notices with the corresponding code commits. In > cases with > >> a clear test case demonstrating the bug, we can use git-bisect to > sleuth out > >> the commit that eliminates the failure. However, cases without this > almost > >> invariably defeat my investigative skills. > >> > >> For posterity's sake, and if it's not too much of a hassle, I thought > it might > >> be helpful to have some commits/diffs/comments attached to those "fixed" > >> messages. > >> > >> I will admit to a bit of an ulterior motive here, though. > >> > >> Bill, Eric, and Henry have deep domain knowledge about JE. I am > personally > >> hoping that sharing the diffs would also spark discussion and give a > natural > >> avenue to share and spread such expertise. > >> > >> The gory details are exceptionally interesting! > >> > >> > >> Permit me to query a broader point, though. > >> > >> It strikes me that the git-shortlog on the repo is very short: > >> > >> $ git shortlog --summary > >> 6 Chris Burke > >> 231 Eric Iverson > >> 1430 HenryHRich > >> 1 bill > >> 597 bill lam > >> 3 cdb > >> 3 kbi > >> > >> For the most part, we only have 3 devs, with all of them part of the > old guard, > >> per se. Better yet, Henry has authored over 62% of all commits! > Granted, this > >> only reflects the history from 2016 onward, but my question is this: Do > we have > >> up and coming JE hackers that can pick up the torch when the time comes? > >> > >> > >> Anyway, maybe JSoftware has a vision for the future that I've failed to > pick up > >> on. The ulterior motive behind my "share a bit about the fix" is to > perhaps > >> open a channel with the community that sucks in potential JE devs like > myself! > >> I was just trying to be sneaky about things by suggesting something > very simple > >> and, hopefully, hassle-free. > >> > >> > >> 2!:55 > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > > > > > -- > This email has been checked for viruses by AVG. > https://www.avg.com > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
