Re: ordering events in a swarm ....

[xueyue]

Paul Johnson wrote:
> 
> > - start
> > {
> >   count = 0;
> >   schedule = [Schedule create: globalZone];
> >   [self schedule: 3];
> >    [[schedule activateIn: nil] run];
> >    [schedule at: 7 createActionTo: objecta message: M(actiona)];
> >    [schedule at: 5 createActionTo: objectb message: M(actionb)];
> >   // ...more new schedule for 'schedule' object
> >   // ...
> >    return self;
> > }
> >
> > My original thought was that: 'schedule' object is created, activated,
> > and run at first; then some new objects such as objecta, objectb, ...,
> > are created at some random stages later, and they will randomly send
> > 'schedule' actions, such as actiona, actionb, .....
> > Maybe my original idea was wrong. I will give up trying.
> > Marcus' example currently will help me.
> > Thanks again!
> 
> Just to see if this thread does close off after this, let me make sure I
> understand the problem.  In the code snip above, objecta and objectb DO
> NOT EXIST at the time the start method is executed.  As a result,
> telling the schedule to plan actions for them does nothing.
> 
> In order to rectify this situation, one must first create objects, then
> send a message to the ModelSwarm telling it to place those objects in a
> schedule.
This will explain all problems I met.
In my simulation project, some objects do not exist at the 
beginning, they will be born at random time. That why I created them
after schedule has started running.
Thanks!
> Here is an alternative that I thing might work.  If you change your
> schedule at: command to refer to a list, then objects that are created
> and added to the list would get grabbed by the schedule:
>   [schedule at: 7 createActionForEach: aList message: M(actiona)];
> The object aList must be created before this executes, but it does allow
> the freedom to create objects later, as long as they put themselves in
> aList.
> 
> I've made mistakes of this sort in the past, where code sends messages
> to objects that are not yet created.  It is a frustrating kind of bug
> because you don't necessarily get an error message, its just that
> nothing happens.
> 
> --
> Paul E. Johnson                       email: address@hidden
> Dept. of Political Science            http://lark.cc.ukans.edu/~pauljohn
> University of Kansas                  Office: (785) 864-9086
> Lawrence, Kansas 66045                FAX: (785) 864-5700
> 
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-- 
Dr Xueyue Huang
Center for Transport Studies
Imperial College 
London SW7 2BU

(+44) 171 594 6037

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