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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]> > > wrote: > >> > >> 2008/9/30 Ben Goertzel <[EMAIL PROTECTED]>: > >> > > >> > 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 > > [EMAIL PROTECTED] > > > > "Nothing will ever be attempted if all possible objections must be first > > overcome " - Dr Samuel Johnson > > > > > > > > _______________________________________________ > > Mailing list: > > https://launchpad.net/~opencog-dev<https://launchpad.net/%7Eopencog-dev> > > Post to : [email protected] > > Unsubscribe : > > https://launchpad.net/~opencog-dev<https://launchpad.net/%7Eopencog-dev> > > More help : https://help.launchpad.net/ListHelp > > > > > -- Ben Goertzel, PhD CEO, Novamente LLC and Biomind LLC Director of Research, SIAI [EMAIL PROTECTED] "Nothing will ever be attempted if all possible objections must be first overcome " - Dr Samuel Johnson
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