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This reminds me of the method of calculating Fourier transform by refracting light through a prism and reading off the different frequencies. You get the "calcu

by dhon_ 4y ago

This reminds me of the method of calculating Fourier transform by refracting light through a prism and reading off the different frequencies. You get the "calculation" for free.

nurettin 4y ago
This is solarpunk material.
stackbutterflow 4y ago
Is it calculation or simulation?
- deleted 4y ago
  [deleted]
- Banana699 4y ago
  Not much difference here, Calculation (or, more generally, Computation) is the manipulation of abstract symbols according to pure rules that may or may not represent concrete entities, e.g. the simplification of polynomials according to the rule of adding like powers. Simulation is when we manipulate things (concrete or abstract) according to the rules that govern other concrete things, e.g. pushing around balls in circles to (highly inaccurately) represent the orbit of planets around a star. Not all calculation is simulation, and not all simulation is calculation, but there exists an intersection of both. The key trick you can do with that last category is that when the physical system you're simulating is controllable enough, you can use the correspondence in the other direction: Use the concrete things to simulate the abstract things. It's simulation, because you're manipulating concrete entities according to the rules that govern other entities (who happen to be abstract),but what you're doing also amounts to doing a calculation with those abstract entities.
Enginerrrd 4y ago
Analog computers are pretty awesome! Say you take a standard slide rule with two log scales, and want to do a division problem, x/y. There's more than one way to do it. I can think of at least 3. One of them won't just compute x/y for your particular x, but will compute x/y for ANY x. Accuracy is always the issue with analog stuff, but they sure are neat. Another fun one to contemplate is spaghetti sort. With an analog computer of sufficient resolution, you can sort n elements in O(n). You represent the numbers being sorted by lengths of spaghetti. Then you put them on the table straight up and bring a flat object down until it hits the first and largest piece of spaghetti. You set that down and repeat the process, selecting the largest element of the set every time. I've always liked the idea of hybrid systems. I envision one where you feed the analog part of your problem with a DAC, then get a really close answer up to the limit of your precision from the analog component, then pass that back out to an ADC and you have a very very close guess to feed into a digital algorithm to clean up the precision a bit. I bet you could absolutely fly through matrix multiplication that way. You could also take the analog output and adjust the scale so it's where it needs to be on the ambiguous parts, then feed it back into your analog computer again to refine your results.
- TedDoesntTalk 4y ago
  > spaghetti sort Isn’t this how very old sorting machines with punch cards worked? I’m thinking of the kinds used by the census or voting machines in the late 1800s or early 1900s.
  - TremendousJudge 4y ago
    I think they used radix sort, which is also pretty cool
- hbarka 4y ago
  Where does a doctor’s stethoscope fit in? Other examples: Mechanic’s stethoscope for diagnosing an engine, airplane vibrations to foretell maintenance, bump oscillations to grade quality of a roadway.
teshier-A 4y ago
Surprised to see no mention of LightOn and its Optical Processing Unit !
V-2 4y ago
This perspective fits nicely with the simulation theory. If we accept it, for argument's sake, then what's happening is essentially delegating the computation to the ultra-meta-computer that runs the simulation.
- arrow7000 4y ago
  It also fits nicely with the universe just being mathematically consistent
  - V-2 4y ago
    This misses the "computation" (being shifted from one layer to another) aspect though. Universe being mathematically consistent and being simulated are completely orthogonal concepts.
    - arrow7000 4y ago
      I understood your comment to be an argument in favour of the simulation hypothesis. So my comment says that that doesn't work. On second reading though it seems like all you're proposing is a mental model for 'analog' computation; that it's like outsourcing the computation to a lower level of hardware. Then yes I agree with that.
      - IIAOPSW 4y ago
        The universe working on a computational principle no more entails it being a simulation than the previous "mechanics" based physics entails it being a machine. Its an unfortunate fact of language and history that it is hard to express the idea of "digital physics" without misleading people into a quasi-scientific secular form of Gnosticism (aka: this is the simulation, the real reality and motivations of the people behind it are hidden from us).
      - V-2 4y ago
        Yeah, I'm not advocating the simulation hypothesis as such : ) I'm only saying it fits here nicely as a thought experiment (that's why I emphasized: "for argument's sake"). Its actual correctness is beyond the point. As for the validity of simulation hypothesis itself, I'd say it's essentially religion in disguise*. It's unfalsifiable by definition too, and personally I apply Occam's razor on the idea, but obviously I can't disprove it. The question can't be "is it true", but it's fine to ask "is it a useful (or at least thought-provoking) metaphor?" (in a given context). ___ * Most religions, in my view, can be broken down to the sum of: a) simulation hypothesis of sorts (universe run by Creator), b) code of ethics with mnemonic narratives, c) ceremonies, that covers most of it analytically speaking.
SilasX 4y ago
Like how mirrors "compute" the (appropriately defined) reverse of an image?
ulnarkressty 4y ago
An even better one - holding an image at the focal point of a lens produces its Fourier transform at the focal point on the other side of the lens[0]. It is used for "analog" pattern matching[1]. There is an interesting video explaining this on the Huygen Optics Youtube channel[2]. [0] - https://en.wikipedia.org/wiki/Fourier_optics https://en.wikipedia.org/wiki/Fourier_optics [1] - https://en.wikipedia.org/wiki/Optical_correlator https://en.wikipedia.org/wiki/Optical_correlator [2] - https://www.youtube.com/watch?v=Y9FZ4igNxNA https://www.youtube.com/watch?v=Y9FZ4igNxNA
- dhon_ 4y ago
  Fascinating, thank you for sharing!
alliao 4y ago
oh god, I can see it coming. elaborated analogue music player for a special price. it's using nothing but light. the fuzzy output will be it's feature; sought after by misdirected audiophiles...
sshlocalhost98 4y ago
This is such an interesting way of computation. I watched analog way of computing neural networks by veritasium.

by dhon_ 4y ago

This reminds me of the method of calculating Fourier transform by refracting light through a prism and reading off the different frequencies. You get the "calculation" for free.

nurettin 4y ago

This is solarpunk material.

stackbutterflow 4y ago

Is it calculation or simulation?

deleted 4y ago
[deleted]
Banana699 4y ago
Not much difference here, Calculation (or, more generally, Computation) is the manipulation of abstract symbols according to pure rules that may or may not represent concrete entities, e.g. the simplification of polynomials according to the rule of adding like powers. Simulation is when we manipulate things (concrete or abstract) according to the rules that govern other concrete things, e.g. pushing around balls in circles to (highly inaccurately) represent the orbit of planets around a star. Not all calculation is simulation, and not all simulation is calculation, but there exists an intersection of both. The key trick you can do with that last category is that when the physical system you're simulating is controllable enough, you can use the correspondence in the other direction: Use the concrete things to simulate the abstract things. It's simulation, because you're manipulating concrete entities according to the rules that govern other entities (who happen to be abstract),but what you're doing also amounts to doing a calculation with those abstract entities.

Enginerrrd 4y ago

Analog computers are pretty awesome! Say you take a standard slide rule with two log scales, and want to do a division problem, x/y. There's more than one way to do it. I can think of at least 3. One of them won't just compute x/y for your particular x, but will compute x/y for ANY x. Accuracy is always the issue with analog stuff, but they sure are neat. Another fun one to contemplate is spaghetti sort. With an analog computer of sufficient resolution, you can sort n elements in O(n). You represent the numbers being sorted by lengths of spaghetti. Then you put them on the table straight up and bring a flat object down until it hits the first and largest piece of spaghetti. You set that down and repeat the process, selecting the largest element of the set every time. I've always liked the idea of hybrid systems. I envision one where you feed the analog part of your problem with a DAC, then get a really close answer up to the limit of your precision from the analog component, then pass that back out to an ADC and you have a very very close guess to feed into a digital algorithm to clean up the precision a bit. I bet you could absolutely fly through matrix multiplication that way. You could also take the analog output and adjust the scale so it's where it needs to be on the ambiguous parts, then feed it back into your analog computer again to refine your results.

TedDoesntTalk 4y ago
> spaghetti sort Isn’t this how very old sorting machines with punch cards worked? I’m thinking of the kinds used by the census or voting machines in the late 1800s or early 1900s.
- TremendousJudge 4y ago
  I think they used radix sort, which is also pretty cool
hbarka 4y ago
Where does a doctor’s stethoscope fit in? Other examples: Mechanic’s stethoscope for diagnosing an engine, airplane vibrations to foretell maintenance, bump oscillations to grade quality of a roadway.

teshier-A 4y ago

Surprised to see no mention of LightOn and its Optical Processing Unit !

V-2 4y ago

This perspective fits nicely with the simulation theory. If we accept it, for argument's sake, then what's happening is essentially delegating the computation to the ultra-meta-computer that runs the simulation.

arrow7000 4y ago
It also fits nicely with the universe just being mathematically consistent
- V-2 4y ago
  This misses the "computation" (being shifted from one layer to another) aspect though. Universe being mathematically consistent and being simulated are completely orthogonal concepts.
  - arrow7000 4y ago
    I understood your comment to be an argument in favour of the simulation hypothesis. So my comment says that that doesn't work. On second reading though it seems like all you're proposing is a mental model for 'analog' computation; that it's like outsourcing the computation to a lower level of hardware. Then yes I agree with that.
    - IIAOPSW 4y ago
      The universe working on a computational principle no more entails it being a simulation than the previous "mechanics" based physics entails it being a machine. Its an unfortunate fact of language and history that it is hard to express the idea of "digital physics" without misleading people into a quasi-scientific secular form of Gnosticism (aka: this is the simulation, the real reality and motivations of the people behind it are hidden from us).
    - V-2 4y ago
      Yeah, I'm not advocating the simulation hypothesis as such : ) I'm only saying it fits here nicely as a thought experiment (that's why I emphasized: "for argument's sake"). Its actual correctness is beyond the point. As for the validity of simulation hypothesis itself, I'd say it's essentially religion in disguise*. It's unfalsifiable by definition too, and personally I apply Occam's razor on the idea, but obviously I can't disprove it. The question can't be "is it true", but it's fine to ask "is it a useful (or at least thought-provoking) metaphor?" (in a given context). ___ * Most religions, in my view, can be broken down to the sum of: a) simulation hypothesis of sorts (universe run by Creator), b) code of ethics with mnemonic narratives, c) ceremonies, that covers most of it analytically speaking.

SilasX 4y ago

Like how mirrors "compute" the (appropriately defined) reverse of an image?

ulnarkressty 4y ago

An even better one - holding an image at the focal point of a lens produces its Fourier transform at the focal point on the other side of the lens[0]. It is used for "analog" pattern matching[1]. There is an interesting video explaining this on the Huygen Optics Youtube channel[2]. [0] - https://en.wikipedia.org/wiki/Fourier_optics https://en.wikipedia.org/wiki/Fourier_optics [1] - https://en.wikipedia.org/wiki/Optical_correlator https://en.wikipedia.org/wiki/Optical_correlator [2] - https://www.youtube.com/watch?v=Y9FZ4igNxNA https://www.youtube.com/watch?v=Y9FZ4igNxNA

dhon_ 4y ago
Fascinating, thank you for sharing!

alliao 4y ago

oh god, I can see it coming. elaborated analogue music player for a special price. it's using nothing but light. the fuzzy output will be it's feature; sought after by misdirected audiophiles...

sshlocalhost98 4y ago

This is such an interesting way of computation. I watched analog way of computing neural networks by veritasium.