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Groups > comp.sys.raspberry-pi > #12777
| From | "WJ" <w_a_x_man@yahoo.com> |
|---|---|
| Newsgroups | comp.sys.raspberry-pi, comp.lang.forth |
| Subject | Re: Jazelle? |
| Date | 2016-07-21 10:43 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <nmq8vk$b52$1@dont-email.me> (permalink) |
| References | (3 earlier) <MPG.31f93e8b429c8383989804@172.16.0.1> <nmnge0$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> |
Cross-posted to 2 groups.
Anton Ertl wrote:
> : 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/ ;
Charles Moore said that local variables are harmful,
but Anton had to use them. Imagine how unwritable
and how unreadable his code would have been without them!
It's atrocious enough already.
Testing:
3e0 -10e0 5e0 quadratic ok
.s <0> ok
f. -0.612574113277207 ok
f. -2.72075922005613 ok
Both results are wrong.
Note a very important fact. None of the Forth "gurus"
posting in this thread noticed that his code produces
absolutely incorrect results. Correctness matters
far less than dogmatic devotion to a stone-age language.
Julia:
quad(a,b,c) = (t = -b/2a; q = sqrt(b^2 - 4a*c)/2a; [t+q, t-q])
julia> quad(3,-10,5)
2-element Array{Float64,1}:
2.72076
0.612574
julia> quad(1,2,-8)
2-element Array{Float64,1}:
2.0
-4.0
Employing the other formula, but using a real language (Julia):
calc_q(a, b_2, c) = copysign(sqrt(b_2^2 - a*c), b_2) + b_2
quad(a,b,c) = (q = -calc_q(a, b/2, c); [q/a, c/q])
julia> quad(1,2,-8)
2-element Array{Float64,1}:
-4.0
2.0
julia> quad(3,-10,5)
2-element Array{Float64,1}:
2.72076
0.612574
--
Amazon bans book. After nearly a month on the site, all traces of the book and
its 80 reviews have been removed.
http://jamesfetzer.blogspot.com/2015/11/debunking-sandy-hook-debunkers-5.html
https://www.youtube.com/watch?v=EEl_1HWFRfo
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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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