I would characterize the notion of state in terms of the functionality that the thing whose state we are talking about. Depending on its state, it is does and is capable of doing different things. This is different from thinking of state in terms of measurements. This sense of state is an abstract notion and doesn't tell you how to determine the state something is in. It just tells you what I mean by state.
- When a traffic light is in the red state it emits red light, and it is capable of changing its state to green. - When a traffic light is in the green state it emits green light, and it is capable of changing its state to yellow. - When a traffic light is in the yellow state it emits yellow light, and it is capable of changing its state to red. Since I haven't been following this discussion at all carefully, perhaps this isn't what you are talking about. In that case, sorry for the intrusion. -- Russ *-- Russ Abbott* *_____________________________________________* *** Professor, Computer Science* * California State University, Los Angeles* * My paper on how the Fed can fix the economy: ssrn.com/abstract=1977688* * Google voice: 747-*999-5105 Google+: plus.google.com/114865618166480775623/ * vita: *sites.google.com/site/russabbott/ CS Wiki <http://cs.calstatela.edu/wiki/> and the courses I teach *_____________________________________________* On Sat, Apr 13, 2013 at 7:46 PM, Steve Smith <sasm...@swcp.com> wrote: > Nick - > > It would be difficult to explain this (Marcus' definition of iteration vs > recursion) to you without teaching you several key computer science > concepts which are not necessarily difficult but are very *specific*. > > The first step would be to answer your question of days ago about what a > "System" is. Physicists define System the same way Biologists (or even > Social Scientists) do, just using different components and processes. It > involves the relationship between the "thing" itself (a subset of the > universe) and a model that represents it. > > Therein lies two lossy compressions: 1) Reductionism is at best a > convenient approximation... no subset or subsystem is completely isolated > (unless perhaps somehow what is inside a black hole is isolated from what > is outside, but that might be an uninteresting, degenerate case?); 2) The > model is not the thing... we've been all over this, right? Another lossy > compression/projection of reality. oh and a *third*; 3) We can only measure > these quantities to some degree of precision. > > In a system, a simultaneous measure every quantity of every aspect of the > system is it's "state". In practice, we can only measure some of the > quantities to some precision of some of the aspects, and in fact, that is > pretty much what modeling is about... choosing that subset according to > various limited qualities such as what we *can* measure and with what > level of precision and with a goal in mind of answering specific questions > with said model. > > At this point, we are confronted with "what means State?" > > Your preference for "Analytical Output" vs "State" I think reflects your > attempt to think in terms of the implementation of a model (in a computer > program, or human executed logic/algorithm). The problems with "Analytical > Output" in this context arise from both "Analytical" and "Output". > "Analytical" implies that the only or main value of the "state" is to do > analysis on it. In Marcus example, it's main use is to feed it right back > into an iterated model... no human may ever look at this "state". "Output" > suggests (also) that the state is visible *outside* the system. While > (for analytical purposes) we might choose to capture a snapshot of the > state, it is not an "output", it is just the STATE of the system (see > above). > > Marcus point was that in a recursive *program* (roughly a deterministic > implementation rooted in formal symbol processing, of a model of some > "system"), the "system" is nominally subdivided into physical or logical > subsets or "subsystems" and executed *recursively* (to wit, by subdividing > again until an answer can be obtained without further subdivision). In an > iterative *program*, the entire (sub) system model is executed with initial > conditions (state) one time, then the resulting state of that iteration is > used as the initial conditions for the *next* iteration until some > convergence criteria (the state of the system ceases to change above some > epsilon) is met. > > I hope this helps... and doesn't muddy the water yet more? > > - Steve > > I don't know, I don't speak Haskell. > > --Doug > > On Sat, Apr 13, 2013 at 3:29 PM, Nicholas Thompson < > nickthomp...@earthlink.net> wrote: > >> Could be! >> >> >> >> Ok. Now that that is behind us, what did the message mean? >> >> >> >> N >> >> >> >> *From:* Friam [mailto:friam-boun...@redfish.com] *On Behalf Of *Douglas >> Roberts >> *Sent:* Saturday, April 13, 2013 3:02 PM >> >> *To:* The Friday Morning Applied Complexity Coffee Group >> *Subject:* Re: [FRIAM] Tautologies and other forms of circular >> reasoning. >> >> >> >> Nick, >> >> >> >> I surprised that you are not more conversant in computer languages. >> You're always, well, niggling about the meaning of this word, or that one >> in the context of this or that conversation. >> >> >> >> With computer languages, there are very few ambiguities, contextual or >> other wise. Kind of like mathematics. For one as worried as you often >> appear to be about the true meaning of the written word, I would have >> thought that you would positively revel at the ability to express yourself >> with nearly absolute crystal clarity, no ambiguities whatsoever. >> >> >> >> Could it be that you seek out the ambiguities that are ever present in >> human languages to give yourself something to pounce upon and worry over, >> and to provide the opportunity to engage in nearly endless conversations? >> >> >> >> --Doug >> >> On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson < >> nickthomp...@earthlink.net> wrote: >> >> Can anybody translate this for a non programmer person? >> >> N >> >> >> -----Original Message----- >> From: Friam [mailto:friam-boun...@redfish.com] On Behalf Of Marcus G. >> Daniels >> Sent: Saturday, April 13, 2013 1:10 PM >> To: friam@redfish.com >> Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning. >> >> On 4/12/13 5:40 PM, glen wrote: >> > Iteration is most aligned with stateful repetition. Recursion is most >> > aligned with stateless repetition. >> Purely functional constructs can capture iteration, though. >> >> $ cat foo.hs >> import Control.Monad.State >> import Control.Monad.Loops >> >> inc :: State Int Bool >> inc = do i <- get >> put (i + 1) >> return (i < 10) >> >> main = do >> putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ >> ./foo >> ([6,7,8,9,10],11) >> >> ============================================================ >> FRIAM Applied Complexity Group listserv >> Meets Fridays 9a-11:30 at cafe at St. John's College to unsubscribe >> http://redfish.com/mailman/listinfo/friam_redfish.com >> >> >> ============================================================ >> FRIAM Applied Complexity Group listserv >> Meets Fridays 9a-11:30 at cafe at St. John's College >> to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com >> >> >> >> >> >> -- >> >> *Doug Roberts >> d...@parrot-farm.net* >> >> *http://parrot-farm.net/Second-Cousins*<http://parrot-farm.net/Second-Cousins> >> >> * >> 505-455-7333 - Office >> 505-672-8213 - Mobile* >> >> ============================================================ >> FRIAM Applied Complexity Group listserv >> Meets Fridays 9a-11:30 at cafe at St. John's College >> to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com >> > > > > -- > *Doug Roberts > d...@parrot-farm.net* > *http://parrot-farm.net/Second-Cousins*<http://parrot-farm.net/Second-Cousins> > * > 505-455-7333 - Office > 505-672-8213 - Mobile* > > > ============================================================ > FRIAM Applied Complexity Group listserv > Meets Fridays 9a-11:30 at cafe at St. John's College > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > > > > ============================================================ > FRIAM Applied Complexity Group listserv > Meets Fridays 9a-11:30 at cafe at St. John's College > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com >
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