Computer Old Farts Forum
 help / color / mirror / Atom feed
From: silas poulson <silas8642@hotmail.co.uk>
To: Will Senn <will.senn@gmail.com>
Cc: COFF <coff@minnie.tuhs.org>
Subject: Re: [COFF] Tail-recursion was Re: [TUHS] Lorinda Cherry
Date: Wed, 23 Feb 2022 00:53:04 +0000	[thread overview]
Message-ID: <A2DEB13F-C738-4EC5-A7C4-F54B5B8E9BD0@hotmail.co.uk> (raw)
In-Reply-To: <52dac66b-3f10-fc5f-9325-a8f4f9bdcc99@gmail.com>

Yes! That’s such as fun presentation!

For those who want the fast version, skip to 6:00 mark.

Silas

> On 23 Feb 2022, at 00:48, Will Senn <will.senn@gmail.com> wrote:
> 
> My all time favorite presentation on tail-recursion:
> 
> https://www.youtube.com/watch?v=-PX0BV9hGZY
> 
> 
> On 2/22/22 4:39 AM, Ralph Corderoy wrote:
>> Hi Otto,
>> 
>>> MacOS uses the GNU implementation which has a long standing issue with
>>> deep recursion.  It even cannot handle the tail recursive calls used
>>> here and will run out of its stack.
>> When learning dc and seeing it relied on tail calls, the first thing
>> I did was check it did tail-call elimination, and it did.  That was
>> GNU dc.
>> 
>> Trying just now, I see no growth in memory usage despite heavy CPU load
>> shown by TIME increasing.
>> 
>>     $ dc
>>     !ps u `pidof dc`
>>     USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
>>     ralph    11489  0.0  0.0   2332  1484 pts/1    S+   10:33   0:00 dc
>>     [lmx]smlmx
>>     ^C
>>     Interrupt!
>>     !ps u `pidof dc`
>>     USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
>>     ralph    11489 75.5  0.0   2332  1488 pts/1    S+   10:33   0:46 dc
>> 
>> The memory used remained at that level during the macro execution too,
>> watched from outside.
>> 
>> Do you have more detail on what GNU dc can't handle?  dc without
>> tail-call elimination is a bit crippled.
>> 
> 
> _______________________________________________
> COFF mailing list
> COFF@minnie.tuhs.org
> https://minnie.tuhs.org/cgi-bin/mailman/listinfo/coff

_______________________________________________
COFF mailing list
COFF@minnie.tuhs.org
https://minnie.tuhs.org/cgi-bin/mailman/listinfo/coff

  reply	other threads:[~2022-02-24  0:18 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAKH6PiVi+JoxDG7ACMG5G+qnTkxTMsohGx6Wq3UNVkogO4N0Vg@mail.gmail.com>
     [not found] ` <CAKr6gn2pJROQNr3M+JGU1vs3bRRh3SrTS5N-8w+vWP2oApwmsw@mail.gmail.com>
     [not found]   ` <alpine.BSF.2.21.9999.2202161122500.45073@aneurin.horsfall.org>
     [not found]     ` <202202160754.21G7sbUa011318@freefriends.org>
     [not found]       ` <1nKFRN-4IZ-00@marmaro.de>
     [not found]         ` <8735kig8vb.fsf@vuxu.org>
     [not found]           ` <m27d9tw9fx.fsf@thuvia.hamartun.priv.no>
     [not found]             ` <alpine.BSF.2.21.9999.2202180810480.45073@aneurin.horsfall.org>
     [not found]               ` <4E3028A1-EC08-424A-B814-CC2AEEEAEC7B@iitbombay.org>
     [not found]                 ` <Yg9Z7Y8RK2+GQeDI@clue.drijf.net>
     [not found]                   ` <20220222103948.1B0482206F@orac.inputplus.co.uk>
2022-02-23  0:48                     ` Will Senn
2022-02-23  0:53                       ` silas poulson [this message]
2022-02-23  1:45                       ` Charles H. Sauer (he/him)

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=A2DEB13F-C738-4EC5-A7C4-F54B5B8E9BD0@hotmail.co.uk \
    --to=silas8642@hotmail.co.uk \
    --cc=coff@minnie.tuhs.org \
    --cc=will.senn@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).