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Groups > comp.sys.raspberry-pi > #12768
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Newsgroups | comp.sys.raspberry-pi, comp.lang.forth |
| Subject | Re: Jazelle? |
| Date | 2016-07-20 15:35 -0400 |
| Organization | A noiseless patient Spider |
| Message-ID | <nmojp7$nc1$1@dont-email.me> (permalink) |
| References | (4 earlier) <nmnge0$rri$1@dont-email.me> <2016Jul20.121415@mips.complang.tuwien.ac.at> <nmnvi0$e7s$1@dont-email.me> <2016Jul20.163523@mips.complang.tuwien.ac.at> <nmojh4$ncf$1@dont-email.me> |
Cross-posted to 2 groups.
On 7/20/2016 3:30 PM, gareth G4SDW GQRP #3339 wrote:
> "Anton Ertl" <anton@mips.complang.tuwien.ac.at> wrote in message
> news:2016Jul20.163523@mips.complang.tuwien.ac.at...
>> "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> writes:
>>> "Anton Ertl" <anton@mips.complang.tuwien.ac.at> wrote in message
>>> news:2016Jul20.121415@mips.complang.tuwien.ac.at...
>>>> "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> writes:
>>>>> Consider the solution of the quadratic equation expressed in
>>>>> a HLL ...
>>>>> X = (-B + SQRT ( B**2 - 4*A*C))?2*A
>>>> Which HLL uses "?" as division operator that has lower priority than
>>>> "*"; actually, which HLL has a division operator with lower priority
>>>> than "*"?
>>> A minor typo caused by typing with the shift key held down
>>> And, yes, S/B (2*A) but neither critique answers the HLL versus assembler
>>> criticism.
>> "S/B (2*A)"?
>> What "HLL vs. assembler criticism"?
>> If your example was an attempt to show the superiority of the Fortran
>> notation over the Forth notation, then the fact that you made two
>> errors in this one line was not a good testimonial for the Fortran
>> way.
>>>> Anyway, this way of computing one of the solutions for a quadratic
>>>> equation is bad because it introduces more numerical instability than
>>>> is coming from the problem itself. Read more about how to do it
>>>> better in
>>> Not relevant to demonsrtating the ease of use and built in syntax checking
>>> of a HLL compared to an assembler.
>> So you want to demonstrate the superiority of the Fortran notation
>> with an example that no competent Fortran programmer will write in
>> that way? And then you parenthesize it incorrectly, a mistake that
>> will not be detected by "syntax checking".
>> Interestingly, in <913374461.4045.0.nnrp-04.9e98250c@news.demon.co.uk>
>> (from 1998) Gareth Alun Evans (any relation to you?) gave pretty much
>> the same example (in BASIC syntax, though), and made the same
>> parenthesis omission mistake. Not a testimonial for the qualities of
>> infix syntax.
>> If you write the example in a numerically stable way, you get several
>> smaller statements rather than a big one, more like most real
>> programs, and the difference between infix and postfix becomes
>> smaller. I guess that's why you choose this example; apparently it's
>> hard to come up with another huge formula that many people can relate
>> to. So even if the Fortran notation would be better for writing down
>> one solution of a quadratic equation in a numerically unstable way
>> (and the mistakes of you and Gareth Alun Evans are evidence against
>> this thesis), that says little about the quality of that notation for
>> real (and competently written) programs.
>> Anyway, here's a way to compute the roots (if they are real) without
>> the numeric instability (you still have bad condition when bb/4 and ac
>> cancel each other out, so you may want to compute that part with higher
>> precision).
>> : compute-q { f: a f: b/2 f: c -- q }
>> b/2 b/2 f* a c f* f- fsqrt
>> b/2 f0< if fnegate then \ avoids cancelation by the F+ below
>> b/2 f+ ;
>> : quadratic { f: a f: b f: c -- x1 x2 }
>> a b f2/ c compute-q { f: q }
>> q a f/ c q f/ ;
>
> I regret that you seem to be nit-picking over an irrelevance to the
> discussion
> about readability; you discuss the hairs on the skin of the pig and not the
> flavour
> of the pork.
>
> But your last 7 lines above illustrate so well the unreadability of Forth
> being, as it is,
> an assembly language.
>
> I don't use Fortran
It is only unreadable to those who refuse to learn it. The code Anton
posted is very simple and clear. If you can't understand it either you
have not at all tried to learn the words he used or you simply are not
capable of programming in a new language (to you).
He has mentioned how you made errors in your code that would not have
been picked up by the syntax checker. Syntax does not typically find
logic flaws.
--
Rick C
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Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-18 10:50 +0100
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-19 20:25 -0400
Re: Jazelle? The Natural Philosopher <tnp@invalid.invalid> - 2016-07-20 07:08 +0100
Re: Jazelle? Paul <paul@pcserviceselectronics.co.uk> - 2016-07-20 08:54 +0100
Re: Jazelle? The Natural Philosopher <tnp@invalid.invalid> - 2016-07-20 09:29 +0100
Re: Jazelle? Gordon Henderson <gordon+usenet@drogon.net> - 2016-07-20 12:56 +0000
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-20 14:54 +0100
Re: Jazelle? Folderol <general@musically.me.uk> - 2016-07-20 18:40 +0100
Re: Jazelle? The Natural Philosopher <tnp@invalid.invalid> - 2016-07-20 19:12 +0100
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 15:17 -0400
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-20 20:32 +0100
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 15:37 -0400
CAN / LIN auto bus (was Jazelle?) jeffj@panix.com (Jeff Jonas) - 2016-07-20 17:53 -0400
Re: CAN / LIN auto bus (was Jazelle?) Martin Gregorie <martin@address-in-sig.invalid> - 2016-07-20 22:28 +0000
Re: CAN / LIN auto bus (was Jazelle?) druck <news@druck.org.uk> - 2016-07-20 23:37 +0100
Re: Jazelle? alister <alister.ware@ntlworld.com> - 2016-07-20 13:34 +0000
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 10:26 -0400
Re: Jazelle? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-07-20 19:51 -0400
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-20 10:31 +0100
Re: Jazelle? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-07-20 10:14 +0000
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-20 14:49 +0100
Re: Jazelle? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-07-20 14:35 +0000
Re: Jazelle? mm0fmf <none@invalid.com> - 2016-07-20 17:39 +0100
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-20 20:30 +0100
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 15:35 -0400
Re: Jazelle? "WJ" <w_a_x_man@yahoo.com> - 2016-07-21 10:43 +0000
Re: Jazelle? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-07-21 12:44 +0000
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-21 22:59 +0100
Re: Jazelle? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-07-22 06:42 +0000
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-22 12:03 +0100
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-22 09:05 -0400
Re: Jazelle? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-07-22 19:20 +0300
Re: Jazelle? "WJ" <w_a_x_man@yahoo.com> - 2016-07-25 10:43 +0000
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-26 11:41 +0100
Re: Jazelle? Doug Hoffman <glidedog@gmail.com> - 2016-07-20 06:44 -0400
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-20 14:52 +0100
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 10:52 -0400
Re: Jazelle? alister <alister.ware@ntlworld.com> - 2016-07-20 15:40 +0000
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 11:46 -0400
Re: Jazelle? Robert Riches <spamtrap42@jacob21819.net> - 2016-07-21 01:27 +0000
Re: Jazelle? "A. Dumas" <alexandre@dumas.fr.invalid> - 2016-07-21 05:58 +0200
Re: Jazelle? colonel_hack@yahoo.com - 2016-07-21 16:29 -0700
Re: Jazelle? "A. Dumas" <alexandre@dumas.fr.invalid> - 2016-07-22 01:56 +0200
Re: Jazelle? colonel_hack@yahoo.com - 2016-07-22 14:04 -0700
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-22 11:59 +0100
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 10:56 -0400
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 10:24 -0400
Re: Jazelle? Theo Markettos <theom+news@chiark.greenend.org.uk> - 2016-07-20 14:38 +0100
Re: Jazelle? "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-07-20 14:57 +0100
Re: Jazelle? rickman <gnuarm@gmail.com> - 2016-07-20 10:53 -0400
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