Here are the integers represented by these 10 binary numbers. bitcomb=: 13 :'(x=+/"1 #:i.2^y)#"2#:i.2^y' 3 bitcomb 5 0 0 1 1 1 0 1 0 1 1 0 1 1 0 1 0 1 1 1 0 1 0 0 1 1 1 0 1 0 1 1 0 1 1 0 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 #.3 bitcomb 5 7 11 13 14 19 21 22 25 26 28
Linda -----Original Message----- From: Programming [mailto:[email protected]] On Behalf Of Linda Alvord Sent: Saturday, November 11, 2017 4:49 AM To: [email protected] Subject: Re: [Jprogramming] K-sets - bitmap representation of sets. WAS: Partitions Also since tacit has been an issue: bitcomb ([ = [: +/"1 [: #: [: i. 2 ^ ]) #"2 [: #: [: i. 2 ^ ] Linda -----Original Message----- From: Programming [mailto:[email protected]] On Behalf Of 'Mike Day' via Programming Sent: Friday, November 10, 2017 11:28 AM To: [email protected] Subject: Re: [Jprogramming] K-sets - bitmap representation of sets. WAS: Partitions Nice. Note that d doesn't need to be global. The 63 bit (or 31 for older hardware) limit shouldn't be a problem in practice?! Wondering if it was possible to avoid boxing, I've found this version - not faster, though more parsimonious in space, so probably not for serious use: combbitub =: 4 : 0 assert y<:<:##:_1 (32 b.) 1 lshift =.33 b. or =.23 b. k =. (y->:ix =. i.>:d=.y-x)lshift 1 z =. ,0 l =. 1#~ #k NB. "box-sizes" as successively 1s, i.#k, triangular nums etc. for. i.x do. nz =. _1 lshift z z =. nz or {.k for_j. }. i.#k do. NB. tack on the smaller "boxes" z =. z, (j{k) or (-j{l) {. nz end. l =. +/\. l NB. bump up the box sizes end. #: z ) 3 (combbit -: combbitub) 5 1 Cheers, Mike 10/11/2017 11:46, Erling Hellenäs wrote: > Hi all! > > Bitmap version of comb. Unfortunately handles sets of max 63 items. > > I tried to make a general version, but hit the problem with #: . > > ts'5 combbit 10' > 3.37831e_5 20864 > ts'5 combbool 10' > 3.89148e_5 22400 > ts'5 combREBoss 10' > 5.51649e_5 44416 > ts'5 comb 10' > 3.76319e_5 50944 > > ts'13 combbit 26' > 0.44835 8.03039e8 > ts'13 combbool 26' > 0.880373 1.4314e9 > ts'13 combREBoss 26' > 2.39319 4.22297e9 > ts'13 comb 26' > 2.59969 4.41693e9 > > ts'60 combbit 63' > 0.00416474 5.26221e6 > ts'60 combbool 63' > 0.0534253 1.73281e7 > ts'60 combREBoss 63' > 0.0344776 6.81943e7 > ts'60 comb 63' > 0.310994 1.38554e8 > > combbit=: 4 : 0 > assert y<:<:##:_1 (32 b.) 1 > lshift=.33 b. > or=.23 b. > k=.<"0 (y->:i.>:d=:y-x)lshift 1 > z=. (d$<i.0),<0 > for. i.x do. z=. k (or)&.> ,&.>/\. (_1&lshift)&.> z end. > #: ;z > ) > > Cheers, > > Erling Hellenäs > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ---------------------------------------------------------------------- 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
