I think you have assumed that the user will use these with "0 or only on atomic numbers?
Thanks, -- Raul On Wed, Aug 9, 2017 at 3:39 PM, Louis de Forcrand <ol...@bluewin.ch> wrote: > A few handy tests which are good to know: > > N=: GI *. 1 0 e.~ * NB. naturals > Z=: GI *. R NB. integers > R=: = + NB. reals > C_R=: + = - NB. pure imaginaries (C-.R) > GI=: = <. NB. gaussian integers > > These were made to accept any J number. They could be optimised if one knows > that they are working only with real numbers, for example. In that case > > 1 0 e.~ * > > could be replaced by > >>:&0 > > and the test for reals can be skipped in Z. > > In addition, these work with the mathematical definitions of the different > number sets, not with J's internal storage types. > > Louis > >> On 9 Aug 2017, at 11:42, Skip Cave <s...@caveconsulting.com> wrote: >> >> Martin, >> >> The original problem I was working on was a post on Quora ( >> https://goo.gl/NrZde2). I use these Quora math questions to help sharpen my >> J skills. I try to see if I can "brute force" the solutions using J, while >> most other posters try to solve these things by algebraic manipulation. My >> answer to that question is here: (https://goo.gl/FhdJAg). There are several >> Quora problems that I have posted J solutions for, mostly to show how >> simple a brute force solution can be when using an array language. You can >> find those posts by searching for my name ("Skip Cave") in Quora >> >> In this problem all I really needed to do was to find all the results from >> the equation that were integers, so I used the 0=1|| scheme to find them. >> >> Our discussion on the J forum got me thinking about finding both the >> fractional part and the integer part of numbers, and I thought the pair of >> verbs (fp, ip) would be a nice addition to the Phrases doc, which is >> defined as listing phrases "useful to beginners in learning the language, >> and of continuing use to practical programmers." >> >> Also, when I obtained the fractional part, I wanted to keep the fact that >> the fractional part came from a negative number, hence the attempt to have >> negative fractional parts. >> >> Skip >> >> Skip Cave >> Cave Consulting LLC >> >>> On Wed, Aug 9, 2017 at 9:35 AM, Martin Kreuzer <i...@airkreuzer.com> wrote: >>> >>> From what I've gathered so far is, that people seem to not mind that much, >>> when extracting the fractional part from a (negative) float, they use >>> >>> (1&|) _8.11 >>> 0.89 >>> >>> or >>> >>> (1&#:) _8.11 >>> 0.89 >>> >>> or >>> >>> (**1||) _8.11 >>> _0.11 >>> >>> as long as the integer and fractional part added up produce the original >>> float value. >>> >>> Q: Would somebody care to give a (scaled down) real-world example so as to >>> give me a chance to understand where this ip/fp extraction usually comes >>> into play and what part of the data is used for decision-making..? Thanks. >>> >>> -M >>> >>> >>> >> ---------------------------------------------------------------------- >> 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
