Henry, I can't quite understand your comment. I think you are saying that you transpose the RGB with 0 1&|: but I don't know where to go with u;._3 from there because the RGB data arrives as shape R C 3, I believe.
In light of Robs trimalt (see my comment about using the right tine as a pre-process constant), I'm not even sure whether it is worth pursuing u;._3 any further for my case. But I am still interested in your observations. Thanks, On Thu, Jun 1, 2017 at 2:44 PM, Henry Rich <[email protected]> wrote: > When I do image work I use RGB planes (shape 3 512 512 for example). > u;.n is much faster on rank 2 than on higher ranks. > > Henry Rich > > > On 6/1/2017 2:30 PM, robert therriault wrote: > >> Brian, >> >> I thought that as well, but I just finished a slightly different approach >> where I went directly to the selection of the triples from the matrix. It >> looks more complicated but is at least twice as fast and a third of the >> space. >> >> trim1 =: >@(tess &(cp;._3))@:(<"1) >> 100000 timespacex 'trim1 i. 7 10 3' >> 5.78836e_6 21632 >> >> trimalt=: {~ <@:(>:@:(3 * i.)@:<.@:(%&3)&.>)@:}:@:$ NB. Hook with >> {~ the left tine >> 100000 timespacex 'trimalt i. 7 10 3' >> 2.41935e_6 7040 >> >> 6.17228e_6 21632 >> >> (trim1-:trimh) i."1 _3[\ , >,&3 each {3&+@:i. each 15 ;15 NB. >> combinations from 3 3 3 to 15 15 3 >> 1 >> >> For indices of less than 3 there is a difference in the shape produced, >> so watch out for that boundary. >> >> $ trimalt i. 2 2 3 >> 0 0 3 >> $ trim1 i. 2 2 3 >> 0 0 >> >> Cheers, bob >> >> On Jun 1, 2017, at 11:18 AM, Brian Schott <[email protected]> wrote: >>> >>> That's very thorough and appears to suggest that no dramatic improvements >>> can be made >>> >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > > > --- > This email has been checked for viruses by AVG. > http://www.avg.com > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- (B=) <-----my sig Brian Schott ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
