Hello Andrew;
I'm not clear on the benefits of such an exercise. I don't know whether I
would term the attitude reflected as primitivistic, or simply Luddite. I
recall the problems I worked on which the appearance of these concepts
seemed to cover quite well, so much so that I no longer saw the need to
recall SKAB(stone knives and bearskins) solutions.
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|\/| Randy A MacDonald | APL: If you can say it, it's done.. (ram)
|/\| [EMAIL PROTECTED] |
|\ | |If you cannot describe what you are doing
BSc(Math) UNBF'83 þas a process, you don't know what you're doing.
Sapere Aude | - W. E. Deming
Natural Born APL'er | Demo website: http://156.34.68.20/
-----------------------------------------------------(INTP)----{ gnat }-
----- Original Message -----
From: "Andrew Nikitin" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, July 10, 2006 8:39 PM
Subject: [Jprogramming] Musings on permutation vectors
From: Brian Schott
I have become more and more comfortable with the permutation
vectors associated with grade up and grade down.
Grade and iota (diadic) are two very powerful operations. In good old days
of flat APL 90% (*) of a job now done by cut conjunction, key adverb,
boxing
and each was done by clever applications of diadic iota and grade. Sure,
cut
and key are very straightforward and easy to use and it was a wise choice
to
add them to the language to make it more practical, but the downside is
that
if you do not excersize your grade muscle you will never know true value
of
it and will not be able to use it in nontrivial cases.
To illustrate try to write
grp +//. values
b >./;.1 values
; b <@/:~;.1 values
(all very natural for writing reports operations) without cut, key and
boxing (which were not available in APL)
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