
		CHATTER BOX ABSTRACTION CODE


This distribution contains code that can be used to eliminate chatter
during a QSIM simulation.  I have assumed that recipients of this
package will be using QSIM 2.0.  This is the most recent release of
QSIM.  We have been distributing this version of QSIM for over a year.

More detailed documentation on the techniques employed and the various
control variables can be found in ENV-ELIM-CH.LISP.

To install this patch:

   1.	Place the file

		chatter-box.system

	in the sys-site directory which has been created under the
	QSIM hierarchy when you installed QSIM 2.0.

	OR

	Add the directory that chatter-box.system is in 
	to the value of mk:*central-registry*.
	At this point mk:*central-registry* might be an atom.  It also
	works if it is a list of directories.

   2.	Modify the special variable

		*chatter-dir*

	in this file to point to the directory with the rest of this
	code.

   3.	To load the chatter-box code execute:

		(compile-system 'chatter-box)

	from within the USER package once QSIM has been loaded.

   4.	You can add this call to whatever file you use to normally
	load QSIM.  There is no reason that this code cannot be used
	in your everyday useage of QSIM.

When you load the chatter-box code, a listing of examples which have also
been loaded is provided.  You can run these examples to see how the results
are displayed.

The special variables that control the chatter-box abstraction are:


	*perform-chatter-abstraction*		Turns chatter abstraction on or off
	*trace-chatter-abstraction*		Traces the abstraction process
	*cleanup-chatter-env-graphs*		If you are doing a large simulation and
						run into space problems, set this variable
						to T and it will destroy the limited
						envisionment graphs after they are used
						so that the space can be reclaimed.
	*elim-chat-around-all-new-lms*		Eliminates chatter around landmarks created
						by QSIM.

Also, if chatter around a landmark occurs then add the clause

	  (elim-lm-chat (<var> <lm-name>))

to the qde where the <lm-name> is a user defined landmark.



If you have any questions, please send mail to clancy@cs.utexas.edu.

Dan Clancy  (May 30, 1992)

	
