[ACT-R-users] puzzled by act-r 5.0.6 behavior

[Bruno Emond]

Dan,

Thanks for the explanation. I guess this is a good example of
parallel processing between modules.

Now is there a way to force act-r to wait for the retrieval to be
finished or do I need to add a third production (see below)?

(p ret1
    =goal>
    isa goal
     status retrieve
    ==>
    +retrieval>
    isa c
     =goal>
     status retrieving
    )
(p ret2
    =goal>
    isa goal
     status retrieving
     =retrieval>
    isa c
    ==>
    -goal>
    )
(p ret3
    =goal>
    isa goal
     status retrieving
    ==>
    !output! "Just waiting for my memory to catch up"
    )



On Saturday, Nov 30, 2002, at 01:54 America/Montreal, Dan Bothell wrote:

>
>
> --On Friday, November 29, 2002 4:27 PM -0500 Bruno Emond
> <bruno.emond at nrc-cnrc.gc.ca> wrote:
>
> > I am puzzled by a retrieval behavior in ACT-R 5.
> > It seems that there is a range of activation values for which
> > neither a chunk nor the failure chunked are retrieved.
> >
>
> What's happening is that the next production is firing before the 
> retrieval
> completes, thus canceling the previous attempt.  In the trace the 
> latency
> displayed shows when that retrieval would complete if it wasn't 
> canceled.  So,
> here for instance
>
> > /*
> > Then there is the problematic section. Between an activation of 
> 2.926 and
> > 2.000 nil is returned, not chunk x2 or failure. Even below and 
> activation of
> > 2.000 nil is returned, contrary to the previous example.
> > */
> >
> >   Sources of activation are: nil
> >      Computing a base level of  2.926 from 1 references from 
> creation time
> > 0.000      Computing a base level of  2.926 from 1 references from 
> creation
> > time  0.000   CHUNK X2 Activation  2.926 Latency  0.054
> >   Time  0.500: Ret Fired
> >   Time  0.500: Ret Selected
> > ==> NIL
> >   Sources of activation are: nil
> >      Computing a base level of  2.841 from 1 references from 
> creation time
> > 0.000      Computing a base level of  2.841 from 1 references from 
> creation
> > time  0.000   CHUNK X2 Activation  2.841 Latency  0.058
> >   Time  0.550: Ret Fired
> >   Time  0.550: Ret Selected
>
> chunk X2 will be retrieved at time .554, but the production is 
> selected and
> fired again at time .550 so the retrieval doesn't get a chance to 
> complete.
>
> Hope that clears things up,
> Dan
>
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