Subject:
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RE: AI and even more exiciting stuff
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 19 Oct 1999 15:48:01 GMT
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Original-From:
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Jim Thomas <jim.thomas@trw.com(StopSpam)>
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Viewed:
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1783 times
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> -----Original Message-----
> From: Ralph Hempel [mailto:rhempel@bmts.com]
> Sent: Monday, October 18, 1999 5:54 PM
> To: lego-robotics@crynwr.com
> Subject: RE: AI and even more exiciting stuff
>
>
[snip]
> > can recompile. Am I wrong?
>
> Ummm, respectfully, yes. If the team took days to rework the code when
> control data tables change, then they were not using tools and methods
> appropriate to the task at hand. I'm hoping you weren't "them" :-)
I wasn't them... I was involved with the control system algorithm
development and analysis. This bunch was definitely not using a tool --
they were doing it all by hand. I'm sure they were not doing it right
either because sometimes the computations would blow up. It was treated
like a black art -- which I guess in this case it was. They had spent years
developing then tweaking this code -- all in assembly. I wrote it in C for
a simulation I had in two days. A high level language and floating point
math turned the problem into a trivial one. That was the point I was making
about R&D. If there are ways to get the equivalent or near equivalent
productivity with fixed point than by all means do it. The only time I was
writing SW which may have used it (I was generating a lookup table from a
poly curve fit) I went with floating point because the curve fit was unknown
prior to compilation and it only had to be done at initialization.
> The algorithm is the same whether or not you use fixed point math. The
> constants and their REPRESENTATION may change from floats to fixed,
> but that should be easy to handle.
>
> In most cases, the conversion from floating point to fixed
> point should
> be handled by an automatic tool. I have used awk, perl, and even TCL
> to massage floating point numbers to the appropriate fixed
> point format
> for tables.
>
> Geez, the more we talk about this stuff, the less confident I am that
> anyone is paying attention in school. Or maybe they don't have enough
> real-world experience put into school environmnents - the
> common argument
> being that they're only trying to get the idea across, and
> the execution
> doesn't really matter.
It was not part of my schooling but I wasn't CS. I am mostly certain that
there is not enough real-worldlyness in the school environments but this may
be changing.
> Oops, time to get off the soapbox again, sorry.
Well, maybe you should write a book on it. "The Black Art of Fixed Point
Math: EXPOSED!" -- I'd buy it :-)
>
JT
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Message has 1 Reply:
 | | RE: AI and even more exiciting stuff
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| (...) I've done simulations on spreadsheets and simple scripting languages when it was too much bother to get the C compiler running properly.... (...) Oh Oh, don't tempt me. Cheers, Ralph Hempel - P.Eng ---...--- Check out pbFORTH for LEGO (...) (27 years ago, 19-Oct-99, to lugnet.robotics)
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