The Weekly Pheromone Volume 1, Issue 6

[glen e. p. ropella]

                         The Weekly Pheromone
                          Volume 1, Issue 6
                          December 31, 1996


   The Pheromone will stand to inform users of the activities and
goals of the hive and user community.  Contributions are accepted that
announce Swarm-related events or activities in any of the growing
Swarm colonies around the world.  To contribute, send e-mail to
address@hidden  The Pheromone is mailed out on Tuesday if and only
if there is information to be disseminated.

Table of Contents
-----------------

   I.  Happy New Year!
  II.  Bug in Tcl/Tk 7.5/4.1
 III.  SCL Released

========================================================================

   I.  Happy New Year!

  II.  Bug in Tcl/Tk 7.5/4.1

   There seems to be a raster refresh problem in Tcl/Tk 7.5/4.1.  It
causes the raster to go blank any time it is repositioned on the
screen or any time another window occludes it.  The "changes" file in
the Tk 4.2 release has the following to say about a *very* similar
sounding bug:

----------------- Released 4.1b2, 2/23/96 -----------------------
[...]
3/1/96 (bug fix) Palette management was broken and resulted in
incorrect palette realization and refresh behavior.  Also, images were
being drawn incorrectly if they were attached to widgets that had a
private colormap. (SS)

   This makes me think that Tk 4.2 will not show this behaviour.  And
our sysadmin has installed 7.6/4.2 on our systems here at SFI, so I
will probably get to try it out within the next week.  In the
meantime, however, if this behaviour annoys you, you can either revert
to 7.4/4.0 or, if you're feeling industrious, upgrade to 7.6/4.2 and
let me know how it turns out.  And, of course, I'll post a message 
to swarm-support telling the results of our upgrade.


 III.  SCL (Substrate, Catalyst, Link) Released!

   Barry McMullin has contributed his Swarm app.  It's called SCL and
has been placed in the user contribution area.  SCL is significantly
different from the apps provided with Swarm.  For example, it does not
use the Observer/Model Swarm style.  It uses parameter loading and
saving.  It has a special purpose space editor.  And it has a number
of different kinds of agents which are dynamically inserted and
removed from the space.
   He's also provided links to web pages that describe his research.
I will add those to the user links area on the User Community page
soon; but until then, here are the URLs:

Computational Autopoiesis:  The Original Algorithm
   http://www.eeng.dcu.ie/~autonomy/bmcm9701

SCL:  An Artificial Chemistry in Swarm
   http://www.eeng.dcu.ie/~autonomy/bmcm9702

Source code:
   http://www.eeng.dcu.ie/~autonomy/bmcm9702/scl-0.04.tar.gz
or
   ftp://ftp.santafe.edu/pub/swarm/users-contrib/anarchy/scl-0.04.tar.gz



                              =========

The Swarm Bulletin is created by the members of the Swarm project at
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