We just haven’t paid much attention to it. Can you file a new issue, unless there is already one, which can be bumped?
-viral > On 18-Apr-2015, at 1:44 am, Thomas Covert <[email protected]> wrote: > > Was this issue ever resolved? I'm also interested in seeing a faster > sortrows(), to the extent that this is possible. > > For example, sorting 20 million random Float64s on my machine takes about > 2-2.5 seconds, but a sortrows() on a 20 million by 2 matrix (again, random > Float64 values) takes about 250 seconds. My algorithm theory is rusty here - > is lexicographic sorting THAT much harder than simple sorting? Shouldn't it > be nlogn? > > > > On Sunday, January 18, 2015 at 12:46:36 PM UTC-6, Viral Shah wrote: > Certainly do file an issue with an easy to produce test case. I am pretty > sure we have not paid much attention to sortrows, and there is room for > improvement. > > -viral > > On Sunday, January 18, 2015 at 5:30:38 PM UTC+5:30, Tim Holy wrote: > If you can reduce this to a standalone, runnable test case that uses only > code > from Base, it would be helpful to file an issue. > > --Tim > > On Saturday, January 17, 2015 05:36:36 PM Arch Call wrote: > > Give alg=MergeSort a whirl. The doc says this is slower than alg=QuickSort > > for numeric arrays, but who knows until you try. > > > > On Saturday, January 17, 2015 at 4:57:20 PM UTC-5, Petr Krysl wrote: > > > Hi guys, > > > > > > This one has me scratching my head. > > > > > > Matlab code: > > > > > > function Out =myunique(A) > > > > > > sA=sort(A,2); > > > [sA,rix] = sortrows(sA);; > > > d=sA(1:end-1,:)~=sA(2:end,:); > > > ad=[true; any(d,2)]; > > > iu =find((ad&[ad(2:end);true])==true); > > > Out =A(rix(iu),:); > > > > > > end > > > > > > was rewritten in Julia. Since some of the functionality is different (or > > > slower) as written, I had to rewrite a bit. The surprise was that even > > > after the rewrite the Julia code runs in around 24 seconds whereas the > > > Matlab code gets it done in two seconds. As I went poking around to find > > > what is slow, I found that 95% of the time were spent in the sort() and > > > sortrrows() functions. > > > > > > Any idea of what could cause this slowness? By the way, @code_warntype > > > gives the code a clean bill... So are those two functions somehow slow by > > > themselves? > > > > > > The Julia version of this is posted at > > > https://gist.github.com/PetrKryslUCSD/cde67dfa0f1b0a1f98ac > > > > > > Thanks, > > > > > > Petr >
