All, I agree that the unum for _0.25 should be "_0.5j0" My previous statement was wrong in its declaration of what *should be*, but it wasn't wrong about what *is wrong in the lab*.
I said: "Shouldn't converting _0.25 to a SORN, then back to a J number produce _0j0.5, NOT _0.5? " I should have said: "Shouldn't converting _0.25 to a SORN, then back to a J number produce _0.5j0, NOT _0.5? " The key here is the words "NOT _0.5". Here are the lab results copied directly from the session: JNFS SFJN 0.25 0j0.5 JNFS SFJN _0.25 _0.5 So as I tried to state in my previous post: The lab is producing wrong results for conversions of _0.25 to SORNS and back to J numbers. The lab should produce " _0.5j0 " for the result of JNFS SFJN _0.25 For that matter, the lab produces wrong results for the whole interval from 0 < x < 0.5 JNFS SFJN _0.25 _0.5 JNFS SFJN _0.35 _0.5 JNFS SFJN _0.1 _0.5 JNFS SFJN _0.499 _0.5 JNFS SFJN _0.5 _1r2 I believe that all these results should be " _0.5j0 " in the lab. Then the lab gets it right again once we cross the _1r2 border (heading negatively): JNFS SFJN _0.6 _1j_0.5 Skip Skip Cave Cave Consulting LLC On Wed, Aug 17, 2016 at 10:47 AM, roger stokes <[email protected]> wrote: > Typo in my last: "gives 0.5j0" should be "Gives "_0.5j0" > > Sorry. > > On Wed, Aug 17, 2016 at 4:43 PM, roger stokes <[email protected]> > wrote: > > > 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/forum > >> s.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
