Ooops! it looks like fp2 isn't so good after all. Skip
Skip Cave Cave Consulting LLC On Mon, Aug 7, 2017 at 4:02 PM, Martin Kreuzer <i...@airkreuzer.com> wrote: > Was it meant like that..? > > fp2 0.3 _0.3 3 _3 > 0.3 _0.3 0 _1 > > -M > > > At 2017-08-07 20:38, you wrote: > > It looks like we have two good solutions to find a fractional part: >> >> v >> >> _2.375 _5.84615 _11.4 13.0028 13.0014 13 12.9986 >> fp1=. * * 1|| NB. Martin >> fp2 =. (1&| - 0&>) NB. Bo & Raul collaboration. >> >> fp1 v >> >> _0.375 _0.846154 _0.4 0.0027933 0.00139082 0 0.998621 >> >> fp2 v >> >> _0.375 _0.846154 _0.4 0.0027933 0.00139082 0 0.998621 >> >> >> Also the converse - integer part: >> >> ip=: * * <.@| >> >> ip v NB. Louis >> >> _2 _5 _11 13 13 13 12 >> >> >> These two verbs need to be somewhere in the "Numbers" section of the J >> Phrases doc. Maybe under "8A-Numbers & Counting", or 8C-Representations", >> or "8D-Arithmetic". How do we get them in there? Can I edit the Phrases >> doc? >> >> >> Skip >> >> >> >> Skip Cave >> Cave Consulting LLC >> >> On Sun, Aug 6, 2017 at 11:22 AM, Louis de Forcrand <ol...@bluewin.ch> >> wrote: >> >> > ip would be best implemented as >> >> > ip=: * * <.@| >> >> > as it would return an integer result. >> >> > Louis >> >> > > On 06 Aug 2017, at 12:17, Skip Cave <s...@caveconsulting.com> wrote: >> > > >> > > All, Thanks for the help. >> > > >> > > Here's some real numbers from a problem I'm working on: >> > > Calculate some values from this equation: >> > > v=:2%(3r19-%1 2 3 245 246 247 248) >> > > v >> > > _2.375 _5.84615 _11.4 13.0028 13.0014 13 12.9986 >> > > Raul's first suggestion: >> > > 1|v >> > > 0.625 0.153846 0.6 0.0027933 0.00139082 0 0.998621 >> > > More precision, but signs are wrong on the negative numbers. >> > > >> > > Nolaig's suggestion: >> > > (- <.) v >> > > 0.625 0.153846 0.6 0.0027933 0.00139082 1.77636e_15 0.998621 >> > > Negative signs are still wrong, and the 6th entry should be zero. >> Looks >> > > like a compare tolerance problem. >> > > >> > > Pascal's solution: >> > > >> > > 1 (| |)v >> > > >> > > 0.375 0.846154 0.4 0.0027933 0.00139082 0 0.998621 >> > > Still has the negatives wrong. >> > > >> > > Martin's solution: >> > > fp=.**1|| >> > > >> > > fp v >> > > >> > > _0.375 _0.846154 _0.4 0.0027933 0.00139082 0 0.998621 >> > > Negatives are right, zeroes are right. This fractional part verb >> needs to >> > > be in the documentation as part of the numbers chapter. >> > > >> > > Also the integer part verb: ip=.]-**1|| should be included in the >> > > numbers section as well. >> > > ip v >> > > >> > > _2 _5 _11 13 13 13 12 >> > > >> > > Skip >> > > >> > > Skip Cave >> > > Cave Consulting LLC >> > > >> > > On Sun, Aug 6, 2017 at 6:42 AM, Raul Miller <rauldmil...@gmail.com> >> > wrote: >> > > >> > >> 1&| does work, actually. >> > >> >> > >> And, if you want an offset of -1 on that result when the original >> > >> value was negative, you can use (1&| - 0&>) >> > >> >> > >> Thanks, >> > >> >> > >> -- >> > >> Raul >> > >> >> > >> On Sun, Aug 6, 2017 at 3:19 AM, Martin Kreuzer <i...@airkreuzer.com> >> > >> wrote: >> > >>> In easy steps (and for further reference) ... >> > >>> >> > >>> From these test data (two floats, two integers, different signs), to >> > get >> > >> the >> > >>> fractional parts >> > >>> >> > >>> v=. 2.25 _8.11 16 _3 >> > >>> >> > >>> simply taking the Residue (when dividing by 1) doesn't work (error >> at >> > >>> negative float position) >> > >>> >> > >>> 1|v >> > >>> 0.25 0.89 0 0 >> > >>> >> > >>> So first get Magnitude >> > >>> >> > >>> | v >> > >>> 2.25 8.11 16 3 >> > >>> >> > >>> then take Residue >> > >>> >> > >>> 1 | (| v) >> > >>> 0.25 0.11 0 0 >> > >>> >> > >>> then get the sign right (see Raul's remark below) >> > >>> >> > >>> (*v) * (1 | | v) >> > >>> 0.25 _0.11 0 0 >> > >>> >> > >>> and put it as verb (fp), written as a fork >> > >>> >> > >>> fp=. * * 1|| >> > >>> fp v >> > >>> 0.25 _0.11 0 0 >> > >>> >> > >>> -M >> > >>> >> > >>> >> > >>> At 2017-08-06 02:14, you wrote: >> > >>> >> > >>>> Eh... but that's wrong. You can't add any integer to 0.542857 to >> get >> > >>>> _0.542857. >> > >>>> >> > >>>> If you want signed fractions, you'd need something like (*@] * (| >> |)) >> > >>>> >> > >>>> Thanks, >> > >>>> >> > >>>> -- >> > >>>> Raul >> > >>>> >> > >>>> >> > >>>> On Sat, Aug 5, 2017 at 10:01 PM, 'Pascal Jasmin' via Programming >> > >>>> <programm...@jsoftware.com> wrote: >> > >>>>> combining other answers we get the cute: >> > >>>> >> > >>>>> 1 (| |) _0.542857 _1.1875 1.96552 2.92308 4.13043 5.7 7.82353 >> > 10.8571 >> > >>>>> 15.5455 23.75 >> > >>>> >> > >>>> >> > >>>> >> > >>>> >> > >>>>> ________________________________ >> > >>>>> From: Bill <bbill....@gmail.com> >> > >>>>> To: "programm...@jsoftware.com" <programm...@jsoftware.com> >> > >>>>> Sent: Saturday, August 5, 2017 8:30 PM >> > >>>>> Subject: Re: [Jprogramming] Fractional parts >> > >>>> >> > >>>> >> > >>>> >> > >>>>> this also depends on what do you expect for negative numbers. >> > >>>> >> > >>>>> Sent from my iPhone >> > >>>> >> > >>>>> On 6 Aug, 2017, at 7:35 AM, Skip Cave <s...@caveconsulting.com> >> > >> wrote: >> > >>>> >> > >>>>>> Oops! i meant: >> > >>>>>> >> > >>>>>> How does one find the fractional parts of a vector of floating >> point >> > >>>>>> numbers? >> > >>>>>> >> > >>>>>> 0.542857 1.1875 1.96552 2.92308 4.13043 5.7 7.82353 10.8571 >> 15.5455 >> > >>>>>> 23.75 >> > >>>>>> 41.8 114 247 >> > >>>>>> >> > >>>>>> i want: >> > >>>>>> 0.542857 0.1875 0.96552 0.92308 0.13043 0.7 0.82353 0.8571 5.5455 >> > >> 0.75 >> > >>>>>> 0.8 >> > >>>>>> 0 0 >> > >>>>>> >> > >>>>>> (Last two integers have zero fractional part.) >> > >>>>>> >> > >>>>>> >> > >>>>>> Skip Cave >> > >>>>>> Cave Consulting LLC >> > >>>>>> >> > >>>>>> On Sat, Aug 5, 2017 at 6:30 PM, Skip Cave < >> s...@caveconsulting.com> >> > >>>>>> wrote: >> > >>>>>> >> > >>>>>>> How does one find the fractional parts of a vector of floating >> > point >> > >>>>>>> numbers? >> > >>>>>>> >> > >>>>>>> 0.542857 1.1875 1.96552 2.92308 4.13043 5.7 7.82353 10.8571 >> 15.5455 >> > >>>>>>> 23.75 >> > >>>>>>> 41.8 114 247 >> > >>>>>>> >> > >>>>>>> i want: >> > >>>>>>> 0.542857 0.1875 0.96552 0.92308 0.13043 0.7 0.82353 0.8571 >> 5.5455 >> > >> 0.75 >> > >>>>>>> 0.8 >> > >>>>>>> 114 247 >> > >>>>>>> >> > >>>>>>> Skip >> > >>>>>>> >> > >>>>>>> Skip Cave >> > >>>>>>> Cave Consulting LLC >> > >>>>>> ------------------------------------------------------------ >> > >> ---------- >> > >>>>>> 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/forum >> s.htm >> > >> ------------------------------------------------------------ >> ---------- >> > >> For information about J forums see http://www.jsoftware.com/forum >> s.htm >> > >> >> > > ------------------------------------------------------------ >> ---------- >> > > 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
