Mathematica on iPad

By: Maynard Handley (, October 21, 2017 9:58 am
Room: Moderated Discussions
dmcq ( on October 21, 2017 7:03 am wrote:
> Adrian ( on October 21, 2017 1:49 am wrote:
> > Maynard Handley ( on October 20, 2017 8:16 pm wrote:
> >
> > > ...
> >
> >
> >
> > Thanks for the interesting information.
> >
> >
> > The low performance for multi-precision operations is not surprising.
> >
> > While this version of Mathematica can probably be improved a lot, it cannot not reach parity
> > with x86, because this (support for multi-precision operations) is exactly the area were the
> > ARMv8 ISA is the most deficient compared with the x86 ISA (especially since Broadwell, but
> > also Intel since Nehalem & the AMD before Bulldozer were far above any competition).
> >
> >
> > Other deficiencies of the initial ARMv8 have already been addressed in the later extensions
> > (e.g. atomic operations), but I have not heard anything about any plans for bignums.
> I'm not sure what you mean. As far as I can see the multi-precision ADOX and
> ADCX operations of Broadwell correspond to single instructions including the
> actions on flags on ARMv8 and MULX becomes two instructions on ARMv8.

I explained my take on this in a comment just above, but also you and Adrian need to remember that I did my Macbook Pro testing on an Ivy Bridge, so whatever niceness Broadwell brings to the party, it's not relevant to the leading order difference we're seeing.
Really, like I said, I think it's all the difference between "how can you track overflow bits in C" (via branches) vs how can you do it in assembly (much faster!); though once you have that down, certainly the next step is you want to be able to grab the high bits of multiplication, and for that again you need to go outside C.
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TopicPosted ByDate
Mathematica on iPadMaynard Handley2017/10/20 01:34 AM
  Mathematica on iPaddmcq2017/10/20 07:26 AM
    Mathematica on iPadMaynard Handley2017/10/20 01:41 PM
      Mathematica on iPadMaynard Handley2017/10/20 08:16 PM
        Does this give better formatting?Maynard Handley2017/10/20 08:20 PM
          Does this give better formatting?anon2017/10/20 09:37 PM
            Does this give better formatting?Maynard Handley2017/10/20 10:29 PM
              Does this give better formatting?anon2017/10/21 12:52 AM
                Does this give better formatting?Maynard Handley2017/10/21 09:48 AM
                  Does this give better formatting?anon2017/10/21 10:01 AM
        Mathematica on iPadAdrian2017/10/21 01:49 AM
          Sorry for the typoAdrian2017/10/21 01:51 AM
          Mathematica on iPaddmcq2017/10/21 07:03 AM
            Mathematica on iPadMaynard Handley2017/10/21 09:58 AM
          Mathematica on iPadWilco2017/10/21 07:16 AM
            Mathematica on iPadDoug S2017/10/21 09:02 AM
              Mathematica on iPadMegol2017/10/22 05:24 AM
            clang __builtin_addcllMichael S2017/10/21 11:05 AM
          Mathematica on iPadMaynard Handley2017/10/21 09:55 AM
  Mathematica on iPadAnon2017/10/21 04:20 PM
    Mathematica on iPadMaynard Handley2017/10/21 05:51 PM
      Mathematica on iPadAnon2017/10/21 09:56 PM
        Mathematica on iPadMaynard Handley2017/10/22 12:23 AM
      A quick search shows that Mathematica is using Intel MKLGabriele Svelto2017/10/21 11:38 PM
        A quick search shows that Mathematica is using Intel MKLAnon2017/10/22 05:12 PM
          A quick search shows that Mathematica is using Intel MKLMaynard Handley2017/10/22 06:08 PM
            A quick search shows that Mathematica is using Intel MKLDoug S2017/10/22 10:40 PM
            A quick search shows that Mathematica is using Intel MKLMichael S2017/10/23 05:32 AM
  Mathematica on iPadnone2017/10/22 06:06 AM
    Mathematica on iPaddmcq2017/10/23 03:43 AM
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