Re: [FRIAM] Systems, State, Recursion, Iteration.
Nick, I guess I would call this a functional state. Or perhaps a disposition. You could also (and equally well--or equally badly) use Lewin's phrase the field at the present time. Or rather, since we do want to talk about existents that persist in time but may have different states at different times (or the same state at different times), the field at some time. Or just the field. My vote on my first parenthesis, by the way, is equally badly. Lee 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
Re: [FRIAM] Systems, State, Recursion, Iteration.
Russ, Ok. So, the question is, what is the value added of saying green state rather than just saying that the light is green. Something comes through the gate with the camel, so to speak. What is it? N From: Friam [mailto:friam-boun...@redfish.com] On Behalf Of Russ Abbott Sent: Saturday, April 13, 2013 10:03 PM To: The Friday Morning Applied Complexity Coffee Group Subject: Re: [FRIAM] Systems, State, Recursion, Iteration. Never beaten over the head with hypothetical construct or intervening variable. My notion of state is basic theoretical computer science. How an automaton (a formally defined mechanism such as a Turing Machine, Finite Automaton, etc.) reacts to its input depends on its state. This isn't intended to be particularly sophisticated. It's just a technique used when specifying how things interact with their environments. When a traffic light that controls a crosswalk is in the green state (in your direction) and you press the cross button, it ignores that input. When it's in its red state (in your direction) and you press the cross button, it starts counting down to turning green. How long the countdown will be depends on another element of its state: how much time has passed since the most recent green. -- 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: http://sites.google.com/site/russabbott/ sites.google.com/site/russabbott/ CS Wiki http://cs.calstatela.edu/wiki/ and the courses I teach _ On Sat, Apr 13, 2013 at 8:48 PM, Nicholas Thompson nickthomp...@earthlink.net wrote: Thanks, Steve. Will ponder all of this. Nick From: Friam [mailto:friam-boun...@redfish.com] On Behalf Of Steve Smith Sent: Saturday, April 13, 2013 8:47 PM To: The Friday Morning Applied Complexity Coffee Group Subject: [FRIAM] Systems, State, Recursion, Iteration. 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
Re: [FRIAM] Systems, State, Recursion, Iteration.
Sarbajit, Thanks for your comments/questions about my Fed suggestion. I'm not an engineer and wasn't thinking about a PID control mechanism. (In fact, I had to look it up http://en.wikipedia.org/wiki/PID_controller!) I was leaving the decision about how to move the levers/dials to FED personnel and wasn't thinking about whether there would be a nice algorithm that gave correction values in terms of current error, past accumulated error, and predicted future error. I suspect that macro economics is not yet up to that. But perhaps I underestimate it. I would like to see a futures market in predicted corrections, which might do a good job. Nick, Saying that the light is green is reporting an observation. Saying the light is in a green state is making a statement about the light as a mechanism. As I said, I think of the notion of state as identifying a collection of functionalities. So attributing a green state to the light implies that when in that state it has a specific set of functional attributes. Saying that the light is green doesn't say anything like that. So I'd say that there is a big difference. The light is green is an observation; the light is in a green state claims that when in that state the light acts and is capable of acting in certain ways that may be distinct from how it acts and is capable of acting when in other states. (I say may be because a mechanism may have two distinct states that are indistinguishable wrt their operational characteristics. Have two such states would suggest design redundancy, but I can't deny the possibility. In software one generally doesn't want such states. In engineering systems such redundancy is often created for the sake of safety.) *-- 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 Sun, Apr 14, 2013 at 9:36 AM, Nicholas Thompson nickthomp...@earthlink.net wrote: Russ, ** ** Ok. So, the question is, what is the “value added” of saying “green state” rather than just saying that the “light is green”. Something comes through the gate with the camel, so to speak. What is it? N ** ** *From:* Friam [mailto:friam-boun...@redfish.com] *On Behalf Of *Russ Abbott *Sent:* Saturday, April 13, 2013 10:03 PM *To:* The Friday Morning Applied Complexity Coffee Group *Subject:* Re: [FRIAM] Systems, State, Recursion, Iteration. ** ** Never beaten over the head with “hypothetical construct” or “intervening variable”. My notion of state is basic theoretical computer science. How an automaton (a formally defined mechanism such as a Turing Machine, Finite Automaton, etc.) reacts to its input depends on its state. This isn't intended to be particularly sophisticated. It's just a technique used when specifying how things interact with their environments. ** ** When a traffic light that controls a crosswalk is in the green state (in your direction) and you press the cross button, it ignores that input. When it's in its red state (in your direction) and you press the cross button, it starts counting down to turning green. How long the countdown will be depends on another element of its state: how much time has passed since the most recent green. *-- 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/*http://sites.google.com/site/russabbott/ CS Wiki http://cs.calstatela.edu/wiki/ and the courses I teach *_* ** ** On Sat, Apr 13, 2013 at 8:48 PM, Nicholas Thompson nickthomp...@earthlink.net wrote: Thanks, Steve. Will ponder all of this. Nick *From:* Friam [mailto:friam-boun...@redfish.com] *On Behalf Of *Steve Smith *Sent:* Saturday, April 13, 2013 8:47 PM *To:* The Friday Morning Applied Complexity Coffee Group *Subject:* [FRIAM] Systems, State, Recursion, Iteration. 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
Re: [FRIAM] Systems, State, Recursion, Iteration.
butting in here... Nick, Saying that the light is green is reporting an observation. Saying the light is in a green state is making a statement about the light as a mechanism. As I said, I think of the notion of state as identifying a collection of functionalities. So attributing a green state to the light implies that when in that state it has a specific set of functional attributes. Saying that the light is green doesn't say anything like that. so, if the light is operated by relays, we can check the position of the relays to determine the state of the green light, but if the light *bulb* behind the green lense is burned out, is the light in the green state or not? The relay powering it is. Or do we simply make up another bit of state for whether the light bulb is operational... and then another for whether the lens is covered in snow to the point of being blanked? For the control-systems engineer designing/building/operating the light system the first is paramount, the second is valuable but the third is probably out of scope? To the driver (or the traffic police) all three sum to one simply point: what color is the light? (and on a good day, can I trust it?). - Steve 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] Systems, State, Recursion, Iteration.
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 mailto: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 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 mailto:nickthomp...@earthlink.net wrote: Can anybody translate this for a non programmer person? N -Original Message- From: Friam [mailto:friam-boun...@redfish.com mailto:friam-boun...@redfish.com] On Behalf Of Marcus G. Daniels Sent: Saturday, April 13, 2013 1:10 PM To: friam@redfish.com mailto:friam@redfish.com Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning. On 4/12/13
Re: [FRIAM] Systems, State, Recursion, Iteration.
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
Re: [FRIAM] Systems, State, Recursion, Iteration.
I guess I would call this a functional state. Or perhaps a disposition. But what is interesting to me about this usage of state is the following: . 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 Russ, in your graduate training, did anybody beat you over the head with the terms hypothetical construct and intervening variable? So the lurking question, here, for a behaviorist, is what could meaning mean but the measures by which one accesses it. I think it probably means the network of relations in which the concept resides. So you can have a conversation about unicorns, not because we have ever seen one, but because the concept of a unicorn lives in a network of concepts that are more closely related to things we have seen. Nick From: Friam [mailto:friam-boun...@redfish.com] On Behalf Of Russ Abbott Sent: Saturday, April 13, 2013 9:16 PM To: The Friday Morning Applied Complexity Coffee Group Subject: Re: [FRIAM] Systems, State, Recursion, Iteration. 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: http://sites.google.com/site/russabbott/ 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
Re: [FRIAM] Systems, State, Recursion, Iteration.
Thanks, Steve. Will ponder all of this. Nick From: Friam [mailto:friam-boun...@redfish.com] On Behalf Of Steve Smith Sent: Saturday, April 13, 2013 8:47 PM To: The Friday Morning Applied Complexity Coffee Group Subject: [FRIAM] Systems, State, Recursion, Iteration. 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
Re: [FRIAM] Systems, State, Recursion, Iteration.
Never beaten over the head with “hypothetical construct” or “intervening variable”. My notion of state is basic theoretical computer science. How an automaton (a formally defined mechanism such as a Turing Machine, Finite Automaton, etc.) reacts to its input depends on its state. This isn't intended to be particularly sophisticated. It's just a technique used when specifying how things interact with their environments. When a traffic light that controls a crosswalk is in the green state (in your direction) and you press the cross button, it ignores that input. When it's in its red state (in your direction) and you press the cross button, it starts counting down to turning green. How long the countdown will be depends on another element of its state: how much time has passed since the most recent green. *-- 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 8:48 PM, Nicholas Thompson nickthomp...@earthlink.net wrote: Thanks, Steve. Will ponder all of this. Nick ** ** *From:* Friam [mailto:friam-boun...@redfish.com] *On Behalf Of *Steve Smith *Sent:* Saturday, April 13, 2013 8:47 PM *To:* The Friday Morning Applied Complexity Coffee Group *Subject:* [FRIAM] Systems, State, Recursion, Iteration. ** ** 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
Re: [FRIAM] Systems, State, Recursion, Iteration.
Dear Russ I've read your paper on *how the Fed can fix the economy: *You've programed the states of the economy and frozen the Fed's response in turns of those states like traffic lights. It reminds me of classical control theory - pure and immediate Proportional control to control a single variable. Are there any Is and Ds which are time/rate dependent or is that left up to the Fed? ** On Sun, Apr 14, 2013 at 9:33 AM, Russ Abbott russ.abb...@gmail.com wrote: Never beaten over the head with “hypothetical construct” or “intervening variable”. My notion of state is basic theoretical computer science. How an automaton (a formally defined mechanism such as a Turing Machine, Finite Automaton, etc.) reacts to its input depends on its state. This isn't intended to be particularly sophisticated. It's just a technique used when specifying how things interact with their environments. When a traffic light that controls a crosswalk is in the green state (in your direction) and you press the cross button, it ignores that input. When it's in its red state (in your direction) and you press the cross button, it starts counting down to turning green. How long the countdown will be depends on another element of its state: how much time has passed since the most recent green. *-- 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 8:48 PM, Nicholas Thompson nickthomp...@earthlink.net wrote: Thanks, Steve. Will ponder all of this. Nick ** ** *From:* Friam [mailto:friam-boun...@redfish.com] *On Behalf Of *Steve Smith *Sent:* Saturday, April 13, 2013 8:47 PM *To:* The Friday Morning Applied Complexity Coffee Group *Subject:* [FRIAM] Systems, State, Recursion, Iteration. ** ** 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
