Subject: CCL: religious debate

From: <[email-masked]>
Date: Fri, 11 Feb 94 08:29:39 EST

I usually avoid consuming band width for computational theology (e.g., FORTRAN
vs. C; Vector-parallel vs. scalable PP; etc.) but a recent posting needs a
response, if only to provide a alternate perspective to the "young" readers of
this list.

Edward Volpert writes:

>>	Much of what is written for computers currently is in C or C++.  
>>Yet banks still use Cobol, and Fortran is popular with chemistist.  
>>To be honest, those aren't that readable... you have to train yourself
>>to understand what is going on.  In C, you can write some really bone-head
>>statements.  C++ restricts you somewhat, but if you wanted, you stil can
>>write unreadable code.  

FREDVC:	It is true that you can write incomprehensible code in ANY language.
	However, having just gone through a self-tutorial in C, I consider
	it to be MUCH EASIER to do so in C!!.

>>                   IMHO, it's hard to really optimize fortran code, and
>>the compilers out there can't do it as well as someone can opt C code.
>>If someone wanted to try to re-write HONDO in C, I believe it would run
>>faster.

FREDVC:	I have a problem with parts of this.  

    (a)	I don't consider it to be that hard to optimize FORTRAN.  (I began to
	worry about this 9-10 years ago in a serious way, when our first CRAY 
	came in.)  What I have consistently found is that there are some good 
	programming practices which, if adhered to scrupulously, provide 
	improved performance on a wide variety of platforms including vector 
	machines.  Perhaps your view is shaped by being more experienced in C 
	than in FORTRAN.

    (b) FORTRAN compilers are pretty sophisticated these days.  I am told, in 
	fact, that todays best compilers can beat hand-optimized assembler
	code in many instances.  If this is true, there may not be as much of
	a "C advantage" as one might think.  I have done some simple kernels on 
	a CRAY Y-MP in both C & FORTRAN, and their execution speeds are the 
	same within "experimental error".  It may well be, however, that CRAY
	Research, Inc., has put special effort into insuring "comparability".

>>	Now the real question: Who wants to try that?
>>This debate will not end until someone does just that. Period. When you can
>>compare real applications that are as intensive as HONDO, then well have
>>facts about the best programming lang, not just emotions.  Of course, then
>>we could always try APL for HONDO, perhaps that's faster?  Nahhh...

FREDVC:	This is not as simple as it looks:  (1) Which version of HONDO do we
	use as a reference point, GAMESS-87, GAMESS-92, GAMESS-UK??  (2) Do we
	compare to the FORTRAN code as it stands, or do we allow for its 
	optimization as well??  Do we optimize for a vector-parallel platform 
	or a scalable parallel-processing platform??  etc.

	No criticism is intended; I just want to highlight that this is not
	as simple an issue as it would appear at first glance.
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                           FREDERIC A. VAN-CATLEDGE

Scientific Computing Division         ||   Office: (302) 695-1187 or 529-2076
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The DuPont Company                    ||      FAX: (302) 695-9658
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