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Re: FORTH Trouble--Please Show Me

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From mhx@iae.nl (Marcel Hendrix)
Subject Re: FORTH Trouble--Please Show Me
Newsgroups comp.lang.forth
Message-ID <87851214938435@frunobulax.edu> (permalink)
Date Sun, 21 Oct 2012 23:50:48 +0200
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Paul Rubin <no.email@nospam.invalid> writes Re: FORTH Trouble--Please Show Me
[..]
> Example in Python:
>
>    def square(x):
>      return x*x
>
>    def derivative(f, h):  # approximate numerical derivative
>      def df(x):
>        return (f(x+h) - f(x)) / h
>      return df
>
>    print square(3)  # prints 9
>    print derivative(square,0.0001)(3)   # prints approximately 6

> You could write something like "derivative" in C with function pointers,
> but it would be much messier.
[..]

I doubt the much in "much messier."

-marcel

-- -------------------
ANEW -derivative

: eval ( ? xt -- ? ) ( F: ? -- ? ) EXECUTE ;

: derivative ( xt -- ) ( F: x h -- d )
  LOCAL f   FLOCALS| h x |
  x h F+ f eval   x f eval  F-  h F/ ;

CR 3e FSQR  F.                  \ prints 9
CR ' FSQR 3e 1e-4 derivative F. \ prints approximately 6

\ FORTH> in idata/derivative
\ 9.000000
\ 6.000100  ok

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FORTH Trouble--Please Show Me "Charles Richmond" <numerist@aquaporin4.com> - 2012-10-17 16:56 -0500
  Re: FORTH Trouble--Please Show Me all2001@spambog.com (Wolfgang Allinger) - 2012-10-17 19:11 -0300
    Re: FORTH Trouble--Please Show Me Mark Wills <forthfreak@gmail.com> - 2012-10-18 01:15 -0700
      Re: FORTH Trouble--Please Show Me "Charles Richmond" <numerist@aquaporin4.com> - 2012-10-18 05:25 -0500
  Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-18 00:14 +0200
    Re: FORTH Trouble--Please Show Me Spam@ControlQ.com - 2012-10-17 18:45 -0400
      Re: FORTH Trouble--Please Show Me Anonymous <nobody@remailer.paranoici.org> - 2012-10-18 08:49 +0000
        Re: FORTH Trouble--Please Show Me Spam@ControlQ.com - 2012-10-18 15:58 -0400
          Re: FORTH Trouble--Please Show Me albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-10-18 21:53 +0000
          Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-19 18:39 -0700
            Re: FORTH Trouble--Please Show Me Mark Wills <markrobertwills@yahoo.co.uk> - 2012-10-19 23:22 -0700
            Re: FORTH Trouble--Please Show Me "Charles Richmond" <numerist@aquaporin4.com> - 2012-10-21 13:40 -0500
          Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-19 21:00 -1000
            Re: FORTH Trouble--Please Show Me "A. K." <akk@nospam.org> - 2012-10-20 09:18 +0200
              Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-20 08:40 -1000
          Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-21 12:22 +0200
            Re: FORTH Trouble--Please Show Me Doug Hoffman <glidedog@gmail.com> - 2012-10-21 08:46 -0400
      Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-18 21:08 +0200
        Re: FORTH Trouble--Please Show Me Mark Wills <markrobertwills@yahoo.co.uk> - 2012-10-18 12:29 -0700
  Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-17 20:24 -0700
    Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-19 19:46 -0400
      Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-19 18:46 -0700
        Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-20 21:03 -0400
          Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-20 15:40 -1000
          Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-20 18:52 -0700
            Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-20 16:27 -1000
          Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-20 20:56 -0700
            Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-21 09:40 -0400
              Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-21 12:51 -0700
                Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-21 23:50 +0200
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-21 17:11 -0700
                Re: FORTH Trouble--Please Show Me mhx@iae.nl - 2012-10-22 00:19 -0700
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 00:41 -0700
                Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-22 09:31 -0500
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 08:13 -0700
                Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-22 21:40 +0200
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 13:14 -0700
                Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-22 10:41 -1000
                Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-22 23:21 +0200
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 14:27 -0700
                Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-22 14:16 -1000
                Re: FORTH Trouble--Please Show Me Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-10-23 21:42 +0100
                Re: FORTH Trouble--Please Show Me vandys@vsta.org - 2012-10-22 00:24 +0000
                Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 04:12 -0400
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 01:40 -0700
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 02:39 -0700
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 02:30 -0700
                Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 22:27 -0400
                Re: FORTH Trouble--Please Show Me David Thompson <dave.thompson2@verizon.net> - 2012-11-04 22:18 -0500
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-11-05 15:35 +0100
                Re: FORTH Trouble--Please Show Me humptydumpty <ouatubi@gmail.com> - 2012-10-22 12:22 -0700
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 12:51 -0700
                Re: FORTH Trouble--Please Show Me humptydumpty <ouatubi@gmail.com> - 2012-10-22 23:40 -0700
                Re: FORTH Trouble--Please Show Me anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-23 12:50 +0000
                Re: FORTH Trouble--Please Show Me humptydumpty <ouatubi@gmail.com> - 2012-10-24 09:13 -0700
                Re: FORTH Trouble--Please Show Me anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-25 12:31 +0000
                Re: FORTH Trouble--Please Show Me humptydumpty <ouatubi@gmail.com> - 2012-10-26 09:58 -0700
              Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-21 16:24 -0700
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-22 02:51 +0200
                Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-21 19:55 -0500
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-22 03:02 +0200
                Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 03:50 -0400
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 01:03 -0700
                Re: FORTH Trouble--Please Show Me stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-22 10:12 +0000
                Re: FORTH Trouble--Please Show Me stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-22 10:08 +0000
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-22 18:06 +0200
                Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-22 22:14 +0200
                Re: FORTH Trouble--Please Show Me albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-10-23 00:50 +0000
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-23 03:43 +0200
                Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-23 03:14 -0500
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 19:54 -0700
                Re: FORTH Trouble--Please Show Me Mark Wills <markrobertwills@yahoo.co.uk> - 2012-10-22 22:59 -0700
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-24 09:23 -0700
                Re: FORTH Trouble--Please Show Me stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-23 10:33 +0000
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-24 10:05 -0700
                Re: FORTH Trouble--Please Show Me Doug Hoffman <glidedog@gmail.com> - 2012-10-24 14:56 -0400
                Re: FORTH Trouble--Please Show Me anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-23 11:50 +0000
                Re: FORTH Trouble--Please Show Me stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-23 14:39 +0000
                Application Benchmarks (was: FORTH Trouble--Please Show Me) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-23 15:59 +0000
                Re: Application Benchmarks (was: FORTH Trouble--Please Show Me) stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-24 14:33 +0000
                Re: Application Benchmarks (was: FORTH Trouble--Please Show Me) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-25 14:19 +0000
                Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 03:56 -0400
                Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-21 22:12 -1000
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 02:51 -0700
          Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-21 05:29 -0500
            Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-21 09:35 -0400
            Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-21 15:44 +0200
              Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-21 18:43 -0500
              Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 04:20 -0400

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