> As Henry points out, the NuVoc page is quite a bit clearer on this topic.
Sample google search: site:jsoftware.com inurl:nuvoc complex Quite a bit of reading there, if you have the patience for it (be sure to mix in plenty of trial and error, though, or it's a total snoozer). Thanks, -- Raul On Fri, Jun 30, 2017 at 11:30 PM, Rob Hodgkinson <[email protected]> wrote: > Hi Lawrence, the “ill-formed number” is because "j." is a verb, quite > different to “j” which is part of a noun construct (like 3j4, or 1e3 for > 1000). > > So in your examples ... > > NB. But wait, not so fast: > 1j.(2^0.5)%2 > |ill-formed number > NB. No > > NB. Now try to separate the “j.” verb with a space either side to make it > clear to J that this is not “1jxxx” where J would assume you are trying to > make a complex constant. > 1 j. (2^0.5)%2 > 1j0.707107 > > The reason is that J can also directly interpret ‘complex constants’ entered > directly using the j notation (as a continuous sequence of non-blank chars)… > 3j4 NB. This is a single complex constant 3+i4 > 3j4 > > 3 j4 NB. But now J tries to view this as a list of (3) and (j4) which > which J would assume is (3) and a variable called (j4). > |syntax error > | 3 j4 > > As Henry points out, the NuVoc page is quite a bit clearer on this topic. > > HTH, Regards Rob > > >> On 1 Jul 2017, at 1:14 pm, Lawrence Wickert <[email protected]> wrote: >> >> Hello, I am a old EE still trying to learn. I am a real beginner having no >> end of problems with specifying complex numbers. I am using j64-804 on >> ubuntu 12.04. I am either doing something really stupid or I need to update >> to 806. Updating anything gives me heartburn or worse so I hope it is just >> my misunderstanding of basic principles. Although I have a bad habit of RTFM >> as a last resort I have tried the Dictionary to no avail. I appreciate any >> guidance. >> >> 0j(2^0.5)%2 >> |ill-formed number >> >> 0j((2^0.5)%2) >> |ill-formed number >> >> j.(2^0.5)%2 >> 0j0.707107 >> NB. Eureaka, OK, I get it! >> >> NB. But wait, not so fast: >> 1j.(2^0.5)%2 >> |ill-formed number >> NB. No >> >> 1j(2^0.5)%2 >> |ill-formed number >> NB. Still No >> >> 1+j.(2^0.5)%2 >> 1j0.707107 >> NB. This works! >> >> Let's try to do something with it: >> k=:(0 1+j.(2^0.5)%2 3 4 0 5) >> |length error >> | k=:(0 1 +j.(2^0.5)%2 3 4 0 5) >> >> NB. Maybe parantheses will help: >> k=:(0 (1+j.(2^0.5)%2) 3 4 0 5) >> |syntax error >> | k=:( 0(1+j.(2^0.5)%2)3 4 0 5) >> >> NB. This one has to work: >> k=:(0 1j0.7071 3 4 0 5) >> k >> 0 1j0.7071 3 4 0 5 >> NB. It does but it can't be the only way to do it. >> >> NB. One last rry: >> g=: 1+j.(2^0.5)%2 >> g >> 1j0.707107 >> NB. That's nice. >> >> k=:(0 g 3 4 0 5) >> |syntax error >> | k=:( 0 g 3 4 0 5) >> NB. This isn't nice. >> >> Lost in the high desert of New Mexico, Larry Wickert >> >> ---------------------------------------------------------------------- >> 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
