Re: three by three and two by two rode the six hundred

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From	Don Lancaster <don@tinaja.com>
Newsgroups	comp.lang.postscript
Subject	Re: three by three and two by two rode the six hundred
Date	Sun, 10 Feb 2013 12:00:56 -0700
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On 2/9/2013 1:41 PM, luser- -droog wrote:
> On Saturday, February 9, 2013 1:27:42 PM UTC-6, luser- -droog wrote:
>> Here are two versions of a function to compute 2x2 or 3x3 determinants.
>>
>
> A little less ugly. mat.ps available at http://code.google.com/p/xpost/downloads/detail?name=mat.ps
>
>
> (mat.ps)run
>
> /elem { % M i j
>      3 1 roll get exch get % M_i_j
> } def
>
> /det {
>      dup length 1 index 0 get length ne { /det cvx /typecheck signalerror } if
>      1 dict begin /M exch def
>          M length 2 eq {
>              M 0 0 elem
>              M 1 1 elem mul
>              M 0 1 elem
>              M 1 0 elem mul sub
>          }{
>              M length 3 eq {
>                  M aload pop cross dot
>              }{ /det cvx /rangecheck signalerror } ifelse
>          } ifelse
>      end
> } def
>


Gauss Jordan reduction is vastly better than determinents for most 
equation solving.

< http://www.tinaja.com/glib/gaussjor.pdf >



-- 
Many thanks,

Don Lancaster                          voice phone: (928)428-4073
Synergetics   3860 West First Street   Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml   email: don@tinaja.com

Please visit my GURU's LAIR web site at http://www.tinaja.com

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three by three and two by two rode the six hundred luser- -droog <mijoryx@yahoo.com> - 2013-02-09 11:27 -0800
  Re: three by three and two by two rode the six hundred luser- -droog <mijoryx@yahoo.com> - 2013-02-09 12:41 -0800
    Re: three by three and two by two rode the six hundred John Reiser <jreiserfl@comcast.net> - 2013-02-10 10:48 -0800
    Re: three by three and two by two rode the six hundred Don Lancaster <don@tinaja.com> - 2013-02-10 12:00 -0700

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