[PD] list-sort

[Matt Barber]

So instead, actually implement it in an array and sort it in place!

Very fast.



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
>>
>
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