[gme-users] various complaints about constraints

[Peter Volgyesi]

Hi,
 
To the short-circuit evaluation problem: have you tried to enable
short-circuit logical operators? (File/Display Constraints/Settings)
 
Also, make sure that "Evaluation ends after the first violation" is set on
this page. 
 
--
peter
 
 


  _____  

From: gme-users-bounces at list.isis.vanderbilt.edu
[mailto:gme-users-bounces at list.isis.vanderbilt.edu] On Behalf Of Matthew J.
Emerson
Sent: Sunday, April 18, 2004 7:16 AM
To: gme-users
Subject: [gme-users] various complaints about constraints



I don't think that the constraint manager really evaluates constraints in
the order of their priority.

 

I have two priority-1 constraints that need to be checked before all others,
because if those two constraints evaluate to false then the other
constraints will crash gme.  Well, no matter what priority I make the other
constraints, gme crashes.  If I delete the lower-priority constraints, gme
does not crash.  If I turn my priority-1 constraints into constraint
functions and then call them as part of the lower-priority constraints as
pre-conditions, then gme does not crash.  But I'm going to have a hard time
finding every case where I need to check these pre-conditions and inserting
the necessary function calls.  I'm going to miss some and gme is going to
soundlessly crash when the constraint manager goes into an infinite loop.

 

I think that if the constraint manager would just check my priority-1
constraints first and then stop checking constraints if they evaluate to
false, my life would be much easier.

 

Also, if the "implies" statement used short-circuit evaluation, it would
make my life easier.  For instance if you say "A implies B", and A is false,
then don't check B.

 

Finally, it would be good if some priority levels beyond level-1 could
result in critical evaluations.  Assuming that the constraint manager
eventually checks constraints in priority order as I described above, it
would be good to be able to specify an evaluation order among critical
constraints.

 

--Matt 

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