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Subject: 
Re: recursion (was RE: Would-be hacker queries.)
Newsgroups: 
lugnet.robotics
Date: 
Tue, 11 May 1999 21:54:14 GMT
Original-From: 
Paul Speed <pspeed@augustschell.com&ihatespam&>
Viewed: 
973 times
  
Hi,

Important clarification: "data stack" free recursion.  This is
an important significance.  It's really only useful for systems with
no data stack.... or alternately as an interesting conversation piece.

What's usually more clever is using data recursion instead
of code recursion, or figuring out that your algorithm isn't recursive
in the first place despite how cool it looked. :)

-Paul (pspeed@progeeks.com)

Joel Shafer wrote:

Here is an interesting article on implementing stack free recursion.

http://www.olympus.net/biz/7seas/recurse.html

At 10:36 PM 5/11/99 +0000, you wrote:
In lugnet.robotics, rhempel@bmts.com (Ralph Hempel) writes:
You are right, but recursion carries a terrible price in terms of stack
usage.  Most recursion is useful for implementing search and traversal
algorithms, but unless the hardware supports DEEP stacks for the worst
case, the problem is almost always better solved the iterative way...

Don't modern implementations of Lisp/Scheme/Logo automatically convert tail-
recursion into iteration?

--Todd
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics

Joel Shafer    joel@connect.net

--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics



Message has 2 Replies:
  Re: recursion (was RE: Would-be hacker queries.)
 
(...) Actually, he goes on to show that in some cases you can eliminate call stack recursion using simple transforms as well. (...) For example, JVM does this by keeping a frame stack of methods that have been executed. The interpreter main loop (...) (26 years ago, 11-May-99, to lugnet.robotics)
  Re: recursion (was RE: Would-be hacker queries.)
 
(...) Let me say that I have not looked at the algorythm in question, yet, so forgive me if this is their solution... (...) The SmalltalkVM my last company built used much the same idea, however, one might say that it was a truely recursive (...) (26 years ago, 12-May-99, to lugnet.robotics)

Message is in Reply To:
  recursion (was RE: Would-be hacker queries.)
 
Here is an interesting article on implementing stack free recursion. (...) -- Did you check the web site first?: (URL) (26 years ago, 11-May-99, to lugnet.robotics)

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