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Re: Peter Chen and Charles Bachman

From: Gene Wirchenko <genew_at_mail.ocis.net>
Date: Mon, 14 Jun 2004 09:04:37 -0700
Message-ID: <nhhrc09cfm0puvdgn589961rvu6k1cb6t3@4ax.com>


Brian Inglis <Brian.Inglis_at_SystematicSw.Invalid> wrote:

>On Mon, 07 Jun 2004 11:01:17 -0700 in comp.databases.theory, Gene Wirchenko
><genew_at_mail.ocis.net> wrote:
>
>>Brian Inglis <Brian.Inglis_at_SystematicSw.Invalid> wrote:
>>
>>>On Tue, 25 May 2004 19:01:45 -0700 in comp.databases.theory, Gene
>>>Wirchenko <genew_at_mail.ocis.net> wrote:

[snip]

>>>> One of the fast sorts has a structure whose symmetry wrt to two
>>>>variables is obvious with a couple of gotos, but which is lost with
>>>>structured code.
>>>
>>>Are you perhaps referring to the quicksort partitioning step?
>>>If solution symmetry is lost in "structured" code, blame the
>>>programmer's poorly structured thinking, and not the poorly structured
>>>code.
>>
>> When the code is structured the symmetry is not in the code. The
>>two variables appear quite different in use. Do you have a version
>>that retains the symmetry IN THE CODE?
>
>The only asymmetry below seems to be the optimization that requires
>a specific order of operations to replace element swaps by moves.
>Opinion?

[snipped code]

    It has been over 20 years, it was an instructor's example, and I do not recall exactly which fast sort it was. Your code is way longer than I remember. I grant your code has good symmetry.

Sincerely,

Gene Wirchenko

Computerese Irregular Verb Conjugation:

     I have preferences.
     You have biases.
     He/She has prejudices.
Received on Mon Jun 14 2004 - 11:04:37 CDT

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