opencog-dev team mailing list archive

["Ben Goertzel" <ben@xxxxxxxxxxxx>]

gotcha

but even so: doesn't this violate Linas's immutability assumption somehow?

ben

On Tue, Sep 30, 2008 at 1:58 PM, Joel Pitt <joel.pitt@xxxxxxxxx> wrote:

> As far as I'm aware only the incoming set can change...
>
> The outgoing set is fixed when you add a link to the AtomSpace/AtomTable.
>
> J
>
> On Tue, Sep 30, 2008 at 10:55 AM, Ben Goertzel <ben@xxxxxxxxxxxx> wrote:
> >
> > Also, of course, the ingoing or outgoing set of an Atom may be changed by
> a
> > MindAgent ... why is this not a problem for concurrency?
> >
> > On Tue, Sep 30, 2008 at 1:51 PM, Linas Vepstas <linasvepstas@xxxxxxxxx>
> > wrote:
> >>
> >> 2008/9/30 Ben Goertzel <ben@xxxxxxxxxxxx>:
> >> >
> >> > Linas,
> >> >
> >> > But the truth values, attention values, etc. associated with an Atom
> are
> >> > not
> >> > immutable ...
> >> >
> >> > so for instance, a MindAgent could add a new Version within a
> >> > CompositeTruthValue
> >> > object associated with an Atom ...
> >>
> >> Hmm. Well, if one thread is looking at a truth value while
> >> another is setting it, then, in today's system, there would be
> >> a crash (because the old value is deleted, and
> >> Atom::getTruthValue() returns a reference).
> >>
> >> This could be solved by having AtomTruthValue() return
> >> a copy, instead of a reference; but then one pays the
> >> penalty of creating a copy, for each and every access.
> >> (this is "copy-on-read").
> >>
> >> By contrast, in a garbage-collected system, the worst that
> >> would happen is that someone is looking at an "old, stale"
> >> truth value; as opposed to crashing.  By the principles
> >> of concurrency, there's "no such thing" as an "old stale
> >> value" in between synchronization primitives.
> >>
> >> --linas
> >
> >
> >
> > --
> > Ben Goertzel, PhD
> > CEO, Novamente LLC and Biomind LLC
> > Director of Research, SIAI
> > ben@xxxxxxxxxxxx
> >
> > "Nothing will ever be attempted if all possible objections must be first
> > overcome "  - Dr Samuel Johnson
> >
> >
> >
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-- 
Ben Goertzel, PhD
CEO, Novamente LLC and Biomind LLC
Director of Research, SIAI
ben@xxxxxxxxxxxx

"Nothing will ever be attempted if all possible objections must be first
overcome "  - Dr Samuel Johnson