Skip,
you wrote "Shouldn't converting _0.25 to a SORN, then back to a
J number produce _0j0.5, NOT _0.5? "
I believe the result given is correct, because _0.25 is in the
interval (_0.5 0) in 4-bit precision.
A =: SFJN _0.25
(> A) # UNUMS
+------+
¦_1r2 0¦
+------+
Rendering this as a complex number, with real for lower bound _1r2
and imaginary for upper bound 0 gives 0.5j0 which is presented by J
as a real number because imag = 0
] B =: JNFS A
_0.5
datatype B
complex
B = _0.5j0
1
I rest my case.
These conversions are not yet finished nor documented, in fact the whole
thing is pretty rough. On that subject, let me mention that until I get it
cleaned up, users should avoid one-character lower case variables, because
of my sloppy style of doing global assigns to what should be local.
I thought it would be best to use rationals for the values, rather than
reals,
so that the computations for the lookup tables would be exact.
Regards
On Wed, Aug 17, 2016 at 3:02 PM, Skip Cave <[email protected]> wrote:
> Playing with 4-bit unums (compact SORNS), I thought I would see how the
> J-to-SORN & SORN-to-J conversions worked:
>
> JNFS SFJN _3
>
> __j_2
>
> JNFS SFJN _2.5
>
> __j_2
>
> JNFS SFJN _2
>
> _2
>
> JNFS SFJN _1.5
>
> _2j_1
>
> JNFS SFJN _1
>
> _1
>
> JNFS SFJN _0.5
>
> _1r2
>
> JNFS SFJN _0.25
>
> _0.5 NB. ??
>
> JNFS SFJN _0
>
> 0
>
> JNFS SFJN 0
>
> 0
>
> JNFS SFJN 0.25
>
> 0j0.5
>
> JNFS SFJN 0.5
>
> 1r2
>
> JNFS SFJN 0.75
>
> 0.5j1
>
> JNFS SFJN 1
>
> 1
>
> JNFS SFJN 1.5
>
> 1j2
>
> JNFS SFJN 1.75
>
> 1j2
>
> JNFS SFJN 2
>
> 2
>
> JNFS SFJN 2.5
>
> 2j_
>
> JNFS SFJN 3
>
> 2j_
>
> JNFS SFJN _
>
> 2j_
>
> JNFS SFJN __
>
> __
>
>
> This would have been easier if JNFS and SFJN could handle vectors. In any
> case, everything looked good, once I understood how Roger was representing
> intervals in J as complex numbers, EXCEPT converting _0.25. Shouldn't
> converting _0.25 to a SORN, then back to a J number produce _0j0.5, NOT
> _0.5?
>
>
> Skip
>
>
> Skip Cave
> Cave Consulting LLC
>
> On Wed, Aug 17, 2016 at 7:21 AM, Skip Cave <[email protected]>
> wrote:
>
> > Is there a way for the unum lab to discover where it was started from,
> and
> > then set the working directory to that location, rather than having the
> > user have to set the directory?
> >
> > Skip
> >
> > Skip Cave
> > Cave Consulting LLC
> >
> > On Wed, Aug 17, 2016 at 6:47 AM, roger stokes <[email protected]>
> > wrote:
> >
> >> Dear All,
> >>
> >> Please accept my apologies for wasting your time, and my thanks
> >> for your patience, persistence and help.
> >>
> >> Skip, Raul, Vijay, you are quite right about 1 !: 44 .
> >> Instead of cd .... I should have said
> >>
> >> 1 !: 44 'yourdirectory' NB. full pathname is recommended
> >>
> >>
> >> Vijay, I made a correction following your mention of general/misc/fndef
> .
> >> This file should not be needed.
> >>
> >>
> >> Bob, thanks for the suggestion - it's a good way to get the lab
> started
> >> but there is still the need to find the other scripts. I will ponder
> this
> >> and see if there is a better way than as it is.
> >>
> >> Bill, thanks for the information about jconsole - I didn't know this
> >> and am very glad you mentioned it.
> >>
> >> I have now uploaded a corrected version to
> www.learningj.com/unumslab.zip
> >> .
> >> However, I hope, I believe, that the VERSION YOU ALREADY HAVE should
> run
> >> OK by doing this:
> >>
> >> 1 !: 44 'yourdirectory'
> >>
> >> first =: {. NB. workaround for Vijay's issues
> >> snd =: 1 & {
> >>
> >> load 'labs/labs'
> >>
> >> lab_jlab_ 'unums.ijt'
> >>
> >>
> >> Thanks again, everyone
> >>
> >> On Wed, Aug 17, 2016 at 4:12 AM, bill lam <[email protected]> wrote:
> >>
> >> > In the readme, it said
> >> > ... jconsole doesn't support labs
> >> >
> >> > This is incorrect. One can run labs on jconsole
> >> > and type labrun_jlab_ '' (and up arrow to recall)
> >> > to advance.
> >> >
> >> > Вт, 16 авг 2016, roger stokes написал(а):
> >> > > Dear All,
> >> > >
> >> > > I've heard it said that you don't understand a subject
> >> > > unless you can explain it to a computer. With that in mind
> >> > > I've attempted a software implementation of Gustafson's Unums 2.0
> >> > >
> >> > > ( http://www.johngustafson.net/presentations/Unums2.0.pdf ).
> >> > >
> >> > > If anyone is interested, there is a demo available in the
> >> > > form of a J lab. To run the lab
> >> > >
> >> > > Download www.learningj.com/unumslab.zip
> >> > >
> >> > > Unzip into any convenient directory
> >> > >
> >> > > Follow directions in the readme file
> >> > >
> >> > > Comments and criticisms appreciated.
> >> > >
> >> > > Regards
> >> > > ------------------------------------------------------------
> >> ----------
> >> > > For information about J forums see http://www.jsoftware.com/forum
> >> s.htm
> >> >
> >> > --
> >> > regards,
> >> > ====================================================
> >> > GPG key 1024D/4434BAB3 2008-08-24
> >> > gpg --keyserver subkeys.pgp.net --recv-keys 4434BAB3
> >> > gpg --keyserver subkeys.pgp.net --armor --export 4434BAB3
> >> > ------------------------------------------------------------
> ----------
> >> > 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
>
----------------------------------------------------------------------
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