(I forgot about that. It would have to go too, in such a mode. Fortunately
avx512 has an (almost) full-width integer multiply. Or do it with extendeds,
which should be the same speed once I'm done with them.)
On Mon, 9 Jan 2023, Henry Rich wrote:
The implementation is floating point.
Henry Rich
On Mon, Jan 9, 2023, 8:24 PM Marshall Lochbaum <mwlochb...@gmail.com> wrote:
The matrices in my example are integral.
Marshall
On Mon, Jan 09, 2023 at 05:20:49PM -0800, Elijah Stone wrote:
> I've thought in the past that it would be nice to have a mode for
> reproducible fp, but there is none yet (try +/ vs ([+])/). But it is
moot
> in this case, as the matrices in question were integral.
>
> (I don't think strict interpretation per se is necessary; just something
> reliable and consistent. EG I imagine picking and committing to a way of
> associating +/ which requires log space but admits efficient
implementation
> on any sort of parallel architecture.)
>
> On Mon, 9 Jan 2023, Marshall Lochbaum wrote:
>
> > I don't think you'd want to reorder matrix multiplications as that can
> > change the results by an arbitrary amount. Here's an example where
> > multiplication on one side cancels but not on the other side.
> >
> > (+/ .*&.>/ , +/ .*&.>~/@:|.) 1e6 1e7;(1e13+=i.2);1 _1
> > ┌────────┬──────────┐
> > │_9000000│_8.99482e6│
> > └────────┴──────────┘
> >
> > Marshall
> >
> > On Mon, Jan 09, 2023 at 01:45:32PM -0500, Henry Rich wrote:
> > > If f is known to be associative, f/\ proceeds from start to end in
linear
> > > time. Elijah has thoughts about how you could inform the
interpreter that a
> > > function is associative. Till that is implemented, you can use
f/\.&.|.
> > > which has linear time, or you can use Fold.
> > >
> > > Henry Rich
> > >
> > > On 1/9/2023 1:23 PM, Omar Antolín Camarena wrote:
> > > > Am I right in thinking that the J interpreter does use a linear
time algorithm for u/\ for some u including + and *? If so, maybe the case
of +/ . * is worth adding.
> > > >
> > >
> > >
----------------------------------------------------------------------
> > > For information about J forums see
http://www.jsoftware.com/forums.htm
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
