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Groups > comp.lang.forth > #19935

Re: OT: ANS Forth

From Paul Rubin <no.email@nospam.invalid>
Newsgroups comp.lang.forth
Subject Re: OT: ANS Forth
Date 2013-02-23 00:31 -0800
Organization Nightsong/Fort GNOX
Message-ID <7xehg7ph2g.fsf@ruckus.brouhaha.com> (permalink)
References (3 earlier) <20130219214611.21680.52657@Nokia-N810-43-7> <51ef1ca5-e3de-42fd-acbd-289de46a90a6@googlegroups.com> <kg53mm$bf5$1@online.de> <7xa9qx4lmi.fsf@ruckus.brouhaha.com> <BIOdneMR_PUj8rvMnZ2dnUVZ_tOdnZ2d@supernews.com>

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Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
> You have a robot arm.  Each axis has a PID task running.  These tasks
> either hold the axis steady, or if a control task tells it to move,
> moves it.  Consider, just for a moment, what happens if you stop PID
> tasks to single-step through some code or inspect a value.

Disclosure: I've never worked on hard-real-time stuff, so maybe my
picture of this kind of coding is unrealistic.  But I'd imagine using
some combination of:

1) stopping the arm when it misbehaves, so that debugger inspection
happens with the arm not moving, and/or

2) using a simulator instead of the actual robot mechanism for debugging
the control software, to the extent possible,

3) modelling the entire system in something like Matlab before even
messing with the physical robot or with fixed-point Forth code.  That
gives you something to compare your Forth program's behavior against.

> If you need to know the value of Y you can just look at it; if it's
> changing rapidly you need a trace.

OK, you've got a trace: you've recorded all the sensor readings and
motor signals while the arm was running, including when it started
misbehaving after some particular motions.  Your Forth algorithm's
output are reasonably close to the more precise Matlab output over most
of the test, but they go seriously wrong at a particular place.  So now
you've got a misbehaving, serial numerical algorithm to debug,
completely separated from the realtime aspect.  It is crunching a bunch
of numbers and going wrong someplace.  

Unless the calculation was horribly complex, I'd tend to approach that
sort of problem by single stepping the program and observing the
intermediate results until I saw something go wrong.

Another place where I find single stepping incredibly useful is in just
understanding what a big unfamiliar piece of code is doing.  E.g.  the
program is building a certain output and I can see where the result
becomes available, and I have to add a feature somewhere before that.
How did the output get to be what it is?  I send in some input,
and start single stepping, observing, interacting, exploring.

The old Lisp Machine environments were fantastically good at this sort
of thing, one reason I regret never having used them.  It sounds very
much in the spirit of Forth as well, so I'm really surprised that the
Forthers here aren't embracing it.

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3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 22:51 +0100
  Re: 3D-graphics calculations using integers? "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-02-07 22:08 +0000
  Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 14:32 -0800
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 23:40 +0100
      Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 17:06 -0800
      Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 17:07 -0800
  Re: 3D-graphics calculations using integers? Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-07 14:36 -0800
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 23:46 +0100
      Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-07 16:38 -1000
        Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 10:22 +0100
      Re: 3D-graphics calculations using integers? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-08 10:26 +0000
  Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-07 12:50 -1000
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:15 +0100
      Re: 3D-graphics calculations using integers? kenney@cix.compulink.co.uk - 2013-02-08 14:51 -0600
        Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:02 +0100
  Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-07 18:21 -0500
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:30 +0100
      Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:39 +0100
        Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-07 18:51 -0500
          Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 12:28 +0100
            Re: 3D-graphics calculations using integers? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-08 12:25 +0000
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:04 +0100
                Re: 3D-graphics calculations using integers? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-09 15:27 +0000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:36 +0100
            Re: 3D-graphics calculations using integers? Mark Wills <forthfreak@gmail.com> - 2013-02-08 05:01 -0800
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 21:58 +0100
            Re: 3D-graphics calculations using integers? Roberto Waltman <usenet@rwaltman.com> - 2013-02-08 10:08 -0500
              Re: 3D-graphics calculations using integers? Roberto Waltman <usenet@rwaltman.com> - 2013-02-08 10:11 -0500
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:05 +0100
              Re: 3D-graphics calculations using integers? Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-08 08:29 -0800
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 18:48 +0100
            Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-08 17:20 -0500
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 23:32 +0100
                Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-09 23:57 -0500
              Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-08 15:02 -1000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 02:24 +0100
                Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-08 15:58 -1000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:43 +0100
                Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-09 10:03 -1000
                Re: 3D-graphics calculations using integers? "Ed" <invalid@nospam.com> - 2013-02-10 11:35 +1100
                Re: 3D-graphics calculations using integers? humptydumpty <ouatubi@gmail.com> - 2013-02-08 23:48 -0800
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:37 +0100
                OT: ANS Forth Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 17:27 +0100
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-09 10:06 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-09 12:26 -0800
                Re: OT: ANS Forth Elizabeth D Rather <erather@forth.com> - 2013-02-09 14:38 -1000
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-22 12:52 -0500
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-22 09:25 -1000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-10 08:15 -0600
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-10 23:34 -0800
                Re: OT: ANS Forth Josh Grams <josh@qualdan.com> - 2013-02-11 22:14 +0000
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-11 13:34 -1000
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-11 11:52 +1100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-10 17:11 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-10 22:06 -1000
                Re: OT: ANS Forth "Charles Childers" <crc@retroforth.org> - 2013-02-11 17:17 -0500
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-13 11:42 +1100
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-12 16:07 -1000
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-15 09:42 +1100
                Re: OT: ANS Forth Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-15 00:16 +0100
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-17 16:05 +1100
                Re: OT: ANS Forth Howerd <howerdo@yahoo.co.uk> - 2013-02-17 04:16 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-17 13:12 +0000
                Re: OT: ANS Forth Howerd <howerdo@yahoo.co.uk> - 2013-02-17 09:15 -0800
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-19 09:35 -0800
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-19 19:25 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-19 15:35 -0600
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 00:37 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 23:07 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 01:38 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 08:50 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 15:44 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 03:41 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 20:00 -0800
                Re: OT: ANS Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-24 13:49 +0000
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 15:04 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 14:52 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 23:51 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 16:23 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-21 03:55 -0600
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-22 13:01 -0500
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-22 12:26 -0600
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-19 21:54 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-19 18:21 -0600
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-20 08:45 -0800
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-20 11:01 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 11:25 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 00:22 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 22:50 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 01:08 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-21 12:42 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-21 13:50 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 09:36 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:32 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:50 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 03:03 +0100
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-21 09:12 -0800
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:38 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 09:01 -1000
                Re: OT: ANS Forth mhx@iae.nl (Marcel Hendrix) - 2013-02-22 00:05 +0200
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-21 13:24 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 09:33 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-21 13:04 -0600
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:41 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:31 -0800
                Re: OT: ANS Forth "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-02-23 09:15 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-23 04:33 -0600
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-23 13:49 +0000
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-23 13:35 -0500
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-23 13:46 -0500
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 15:26 -0800
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-24 09:41 -0500
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 09:09 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:37 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-23 13:57 +0000
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-23 08:47 -1000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:27 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:16 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-23 04:36 -0600
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-23 16:52 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 12:39 -0800
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-25 16:27 +0000
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-23 18:08 -0500
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 02:20 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 20:16 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 16:04 +0100
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-25 17:12 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 20:44 +0100
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 16:45 +0100
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-24 02:09 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 04:03 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-25 17:58 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 20:57 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-02 16:43 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-03-02 18:14 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-03 13:56 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-24 03:45 -0600
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-13 04:12 -0600
                Re: OT: ANS Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-13 12:24 +0000
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-11 14:41 +0000
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-11 19:44 +0000
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-11 21:14 +0000
                Re: 3D-graphics calculations using integers? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-09 18:14 -0600
                Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-10 00:06 -0500

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