[PD] list-sort

[Martin Peach]

Matt Barber wrote:
>
>So instead, actually implement it in an array and sort it in place!
>
>Very fast.
>

(Of course it works for lists of numbers only). It would be even faster to 
have coded externals that operate on tables like that. I have made one, 
[mrpeach/tabfind], that gives the nth index of a number or list of numbers 
found in a table. This follows Miller's suggestion that tables are the right 
way to manipulate strings without adding them to the symbol table. An 
external that sorted a table in place would be very fast.


Martin






>
>On Tue, Dec 2, 2008 at 10:16 PM, Matt Barber <brbrofsvl at gmail.com> wrote:
> > Also, I find it extremely tempting to think of a list of numbers as an
> > array[ ], but this analogy won't hold because you can't operate on the
> > list in-place -- I'm sure a lot of the overhead is in feeding entire
> > lists back and forth and around to the different parts of the patches.
> >  Maybe the algorithm with the fewest total [list] operations sometimes
> > wins out over the algorithm that's in general more efficient.
> >
> > Matt
> >
> >
> >
> > On Tue, Dec 2, 2008 at 10:01 PM, Matt Barber <brbrofsvl at gmail.com> 
>wrote:
> >> For what it's worth,
> >>
> >> I just ran one possible benchmark on the [list-*sort] abstractions
> >> submitted recently, using [list-random] and [realtime].
> >>
> >> I think overall the overhead for [list-sort] is much less than for
> >> [list-shellsort] -- for short lists (<100) it takes about half the
> >> time.  [list-shellsort] is a bit quicker when the variance of the
> >> elements is smaller (which makes sense because the more alike the
> >> elements are the less the innermost loop will have to run) -- but
> >> [list-sort] still beats it.  I have a feeling that some of the
> >> overhead in [list-shellsort] is in the [list-swap] function and other
> >> list-abs objects, which are a little too feature-rich and/or
> >> idiot-proof for this particular use.  =o)
> >>
> >>
> >> However, after some trial and error with [list-sort] I found I am
> >> unable to sort a list of more than exactly 121 elements without
> >> freezing Pd -- 122 and up will freeze it.  This is because the main
> >> loop is not controlled with an [until] -- I think you can see the
> >> structure of [list-drip] for similar reasoning (the [until] is not
> >> "needed" logically, but helps with long lists to do it in steps).
> >> After implementing the [until] loop, I found that [list-sort] is even
> >> quicker than before, but the efficiency of the [list-shellsort]
> >> algorithm take over for list sizes >450 -- above that [list-shellsort]
> >> is substantially quicker (and quicker yet if the variance is low).  It
> >> beats [list-sort] by half for a list about 1300-1400 elements long or
> >> so (but not within reason -- it still takes about 2 seconds!).
> >>
> >>
> >> I attached the new [list-sort] and the goofy little diagnostic.
> >>
> >> Matt
> >>
> >>
> >>> Date: Tue, 2 Dec 2008 13:59:08 +0100
> >>> From: Frank Barknecht <fbar at footils.org>
> >>> Subject: Re: [PD] list-sort
> >>> To: pd-list at iem.at
> >>> Message-ID: <20081202125908.GJ18987 at fliwatut.scifi>
> >>> Content-Type: text/plain; charset="us-ascii"
> >>>
> >>> Hallo,
> >>>
> >>> oh, and I also now committed two more abstractions that Matt Barber
> >>> sent me offlist, of which one is a sorting abstraction as well. Matt's
> >>> [list-shellsort] uses the Shell sorting algorithm:
> >>> http://en.wikipedia.org/wiki/Shell_sort which generally is a bit
> >>> faster than insertion sort, but I didn't benchmark the two Pd
> >>> implementations (the speed in Pd of course also depends on how much
> >>> element shuffling and list-dripping is needed)
> >>>
> >>> Anyway, currently list-shellsort only does ascending sorting, so I
> >>> just decided to include both Michal's list-sort, which probably is
> >>> easier to understand, and Matt's list-shellsort in the current SVN's
> >>> [list]-abs collection. Choose your poison. ;)
> >>>
> >>> Ciao
> >>> --
> >>> Frank
> >>>
> >>> Michal Seta hat gesagt: // Michal Seta wrote:
> >>>
> >>>> Hi all,
> >>>>
> >>>> It is amazing how we take things for granted.  Most programming
> >>>> languages provide some sort of list sorting function/method.
> >>>> Surprisingly (or not) pd does not (or my search skills are null, or I
> >>>> am not bleeding edge enough).  I needed a solution that works with a
> >>>> vanilla pd.
> >>>>
> >>>> I was almost going to do the academia move and announce a pd exam, 
>and
> >>>> have little pd-bees come up with a solution but I needed it *now* 
>else
> >>>> I would not sleep or have terrible nightmares.  So here it is.  Thank
> >>>> heavens (but give your offerings to fbar's footils shrine) for
> >>>> list-abs.
> >>>>
> >>>> Busy pd-bees, should you care to improve on my solution, please be my
> >>>> guest, I am sure there are better ways of accomplishing this trivial
> >>>> task.  In any case, go forth and sort the world around (or within)
> >>>> you.
> >>>>
> >>>> ./MiS
> >>
> >


><< list-shellsort-tab.pd >>


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