Skip, Thanks for your message and thanks for all the trouble you have gone to. Let me try to explain the results you are seeing.
First, the important thing to note is that J itself displays a complex number with imaginary part zero as looking like a real number. To check this, try entering 0.5j0 _0.5j0 directly into any J session: 0.5j0 _0.5j0 0.5 _0.5 Second, the result you are seeing is indeed complex: Z =: JNFS SFJN _0.25 datatype Z complex but it looks like a real number (and hence your objection) Z _0.5 but it does have the value that you say it should have Z = _0.5j0 1 Hope this is useful Regards On Wed, Aug 17, 2016 at 8:35 PM, Skip Cave <[email protected]> wrote: > 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 > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
