No space saving for 64 bit integers.
-----Original Message----- From: Programming [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Skip Cave Sent: Tuesday, August 8, 2017 23:48 To: programm...@jsoftware.com Subject: Re: [Jprogramming] Fractional parts Don, You're right. Your approach achieves the same result when re-combining the fractional and integer part: ]v=:2%(3r19-%1 2 3 245 246 247 248) ]'i f'=:|:0 1#:v _3 _6 _12 13 13 13 12 0.625 0.153846 0.6 0.0027933 0.00139082 0 0.998621 i _3 _6 _12 13 13 13 12 f 0.625 0.153846 0.6 0.0027933 0.00139082 0 0.998621 v = i+f 1 1 1 1 1 1 1 However, datatype f floating datatype i floating Where as the original fp/ip verbs give: datatype fpv floating datatype ipv integer So either approach will work, but ip returns integers, while your approach returns floats in both i & f cases. The fact that I originally called the verb the "integer part" probably led to the initial integer solution from the group. I'm not sure what advantages either approach would have, other than a space savings for pure integers. Skip Skip Cave Cave Consulting LLC On Tue, Aug 8, 2017 at 8:04 PM, Don Guinn <dongu...@gmail.com> wrote: > There are many ways to handle the fractional part of a number, > depending on the problem at hand. The real difficulty seems to be > handling negative numbers. I like this, which rounds down negative > numbers. But others might want a different way. > > ]'i f'=:|:0 1#:1.2 3.7 _2.1 > 1 3 _3 > 0.2 0.7 0.9 > i > 1 3 _3 > > f > 0.2 0.7 0.9 > i+f > 1.2 3.7 _2.1 > > On Tue, Aug 8, 2017 at 3:56 PM, Skip Cave <s...@caveconsulting.com> wrote: > > > The purpose of the "negative fractional part" is to satisfy the > > identity condition when the two parts are added back together: > > > > ]v=:2%(3r19-%1 2 3 245 246 247 248) NB. Create some long > > fractional parts. > > > > _2.375 _5.84615 _11.4 13.0028 13.0014 13 12.9986 > > > > > > fp=. * * 1|| NB. The fractional part verb > > > > ip=: * * <.@| NB. The integer part verb > > > > > > ]fpv =: fp v NB. Save the fractional part > > > > _0.375 _0.846154 _0.4 0.0027933 0.00139082 0 0.998621 > > > > > > ]ipv =: ip v NB. Save the integer part > > > > _2 _5 _11 13 13 13 12 > > > > > > > > ]sm =: ipv + fpv NB. Add the two parts back together > > > > _2.375 _5.84615 _11.4 13.0028 13.0014 13 12.9986 > > > > > > NB. The result of adding the two parts should be identical to the > original > > vector. > > > > > > sm = v > > > > 1 1 1 1 1 1 1 > > > > Skip Cave > > Cave Consulting LLC > > > > On Tue, Aug 8, 2017 at 2:14 PM, 'Bo Jacoby' via Programming < > > programm...@jsoftware.com> wrote: > > > > > The integer part a and the fractional part b of a number x > > > is > such > > > that x=a+b and a is an integer and 0<:b and b<1 . I do know of no > > use > > > of a "negative fractional part". > > > > > > Den 20:39 tirsdag den 8. august 2017 skrev Raul Miller < > > > rauldmil...@gmail.com>: > > > > > > > > > I think we've mostly been using the wiki for live documents. (I'm > > > not sure what all would be involved in changing the phrase book.) > > > > > > Thanks, > > > > > > -- > > > Raul > > > > > > > > > On Tue, Aug 8, 2017 at 2:35 PM, Skip Cave > > > <s...@caveconsulting.com> > > wrote: > > > > It looks like we have a reliable solution to find a fractional > > > > part > of > > a > > > > floating point number, while maintaining the sign: > > > > > > > > v > > > > > > > > _2.375 _5.84615 _11.4 13.0028 13.0014 13 12.9986 > > > > > > > > fp=. * * 1|| NB. Thanks to Martin > > > > > > > > fp v > > > > > > > > _0.375 _0.846154 _0.4 0.0027933 0.00139082 0 0.998621 > > > > > > > > > > > > Credit should also go to the people who suggested the building > blocks, > > > e.g. > > > > > > > > (1|y) Raul -- (1||y) Pascal -- (*y) Raul > > > > > > > > It is also nice to have the companion verb - integer part: > > > > > > > > ip=: * * <.@| NB. Thanks to Louis > > > > > > > > ip v > > > > > > > > _2 _5 _11 13 13 13 12 > > > > > > > > > > > > I have needed these functions more than once in my enginering > > > > work. I believe that these two verbs need to be inserted > > > > 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 the document? What section do they fit the > > > > best > > in? > > > > Can I edit the Phrases doc? > > > > > > > > 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/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
