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Article 1832 of comp.ai.philosophy:
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>From: harwood@umiacs.umd.edu (David Harwood)
Newsgroups: comp.ai.philosophy
Subject: Re: Physical limits when programming neurons and minds
Message-ID: <44126@mimsy.umd.edu>
Date: 3 Dec 91 18:30:41 GMT
References: <445@trwacs.UUCP> <44011@mimsy.umd.edu> <341@idtg.UUCP>
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In article <341@idtg.UUCP> dow@idtg.UUCP (Keith Dow) writes:
(replying to me ...)
>
>>	I recall that 17 years ago, or therabouts (to show how out-of-date
>>I am) - it took hundreds of hours of computing by the current state-of-
>>the-art approximate calculation on a CDC Cyber (now extinct species with
>>long words) for solution of Schroedinger's equation for even the simplest 
>>stripped atoms. This was the first "successful" calculation, and nobody 
>>was sure whether it was correct.
>>	Times have surely changed if "drug companies make millions"
>>out of this sort of thing now. (Do their computers suffer side-effects of
>>these calculations?)
>
>Seventeen years ago, in the world of computers, is two years after
>they invented dirt. :-)  Molecular modeling on workstations runs at about
>one third the speed it does on the fastest supercomputers.  The reason
>is the problem is tightly coupled and cannot be vectorized.
>There is a good article on it in the EE Times of a few weeks back.
>
>Workstations speed up about a factor of two every year.  So you will
>see a lot more power coming up.  
\\\\\\\\\\\\\
	Good to know. I should find easier problems involving tightly-
coupled PDEs and a coupon for a state-of-the-art superscalar PC, instead
of beating my head against a CM_2 to get it to cough up a publication.
	Could you briefly review this article (or other references) for
us to make sure we are all talking about the same thing? Drug companies
are solving Schroedinger's "equation" (or "tightly-coupled PDE system"),
as you suggest, for some pretty big molecules? That is - actually solving
S's and not doing some other useful mathematics, perhaps having some of
the same information?
	Could you simply quote a few sentences to reassure me? (Eg 
"Last night we solved S's equation for 'M' on our 100mflop workstation 
here at the lab in the wooded suburbs of Tarrytown.") I would be very
interested to find out more about this - and wonder why I hadn't read
about it in Science News. I'm cancelling my subscription now.
	Thanks for the reference to EE Times. I'll check it out, if the
issue isn't lost enroute through the departments.


