Path: utzoo!utgpu!watserv1!maytag!mks.com!tslwat!louk
From: louk@tslwat.UUCP (Lou Kates)
Newsgroups: comp.lang.apl
Subject: Re: Statistical Functions in J
Message-ID: <414@tslwat.UUCP>
Date: 29 May 91 02:01:57 GMT
References: <1991May12.145907.19563@yrloc.ipsa.reuter.COM> <356@tslwat.UUCP> <1991May21.042804.21102@yrloc.ipsa.reuter.COM>
Reply-To: louk@tslwat.UUCP (Lou Kates)
Organization: Teleride Sage, Ltd., Waterloo
Lines: 37

In article <1991May21.042804.21102@yrloc.ipsa.reuter.COM> hui@yrloc.ipsa.reuter.COM (Roger Hui) writes:
>Lou Kates writes:
>
>> Nevertheless, I believe the key  concept here is not expectation,
>> probability or  measure  but regression and projection. From this
>> viewpoint the old APL's domino  operator (or regression operator)
>> had it correct and the above suggestions are a step backwards.
> 
>I am puzzled.  How would a belief in regression and projection
>instead of expectation as the key concept materially affect
>the design of the primitives m., n., and s.?
                   ^^^^^^^^^^
When everything you can think of gets put into the lanugage its hard
to see how they all qualify as primitive.

> 
>There are many statistical functions worthy of inclusion in the
>language.  We are adding the new functions ...

I guess its whether you believe in parsimony or not.

Personally I   would   rather have   a wider  family of  powerful
operations at my disposal (such as regression, constrained linear
optimization a la simplex  or Karmarker, eigenvalue calculations,
etc.) that are not easily derivable from each other rather than a
large  set  of functions which are all readily derivable from the
ideas of regression  and   projection.  My own preference, and  I
suspect that of many others too, would be  that if   you feel the
need to  have zillions of functions at  your  disposal,  define a
standard library so that you can take them out of the language so
as to keep  the   language  smaller  and more    manageable.   If
performance is the  issue   then   there  is  nothing  to  stop a
particular  implementation  from implementing  certain   standard
library functions in the kernel.

Lou Kates, Teleride Sage Ltd., louk%tslwat@watmath.waterloo.edu
519-725-0646