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> That sounds like the answer summary is “Yes”. ;) Practically speaking digital computers are so fast that the simulation of analog is more or less the same. I

> That sounds like the answer summary is “Yes”. ;) Practically speaking digital computers are so fast that the simulation of analog is more or less the same. In gaming we run entire physics simulations and they are so fast they appear as analog. And these are for real time simulations. We can run simulations slower and at resolution beyond what's possible with analog. First analog would be limited by noise. So there's a limit with resolution here. Digital offers virtually unlimited resolution by using symbols to represent numbers. The advantage of analog here is that at the highest resolution of simulation possible with analog it will be faster than digital. That's all. >We definitely do know how to build analog computers that have function calls. No. A function call involves a stack and saving context onto that stack. An analog computer is a function in itself. There is no "call". I neglected to mention the "delay" from input to output as one replyer mentioned but that's just details. That would be the closest thing to memory since the delay means your accessing a result from the past.

dahart 3y ago
A function “call” is a software abstraction. What you’re calling a function call by defining it as stack based is a pure software abstraction. A stack is one way to implement functions, but not the only way. Capacitors can provide analog immediate access memory. Analog delay lines and feedback circuits can provide conceptually recursive functions, and those are common in analog circuits today. It’s true that analog has limited precision, though no reason you can’t represent higher precision via multiple analog signals, just like how digital requires more bits. All the rest of it still looks to me like you’re making some incorrect assumptions about what’s possible with analog circuitry.
- corethree 3y ago
  A function call is indeed a software abstraction. Outside of software nobody "calls" functions at all. That was my entire point. In mathematics you have function application which is close to the idea of the function call. And this idea also doesn't exist in analog computing. Ironically, Mathematics does model what's going on in an analog computer on a field called signal processing. In signal processing it's called a transform. >It’s true that analog has limited precision, though no reason you can’t represent higher precision via multiple analog signals, You can't. The only way to do this with multiple signals is to make each signal represent a digit or a portion of digits of the final value. But if you did this you'd be going digital. You likely won't be doing binary but it's still digital.
  - dahart 3y ago
    > You can’t Speak for yourself. ;) Depends on how you define “digital”. Digital is typically defined as being based on logic gates, not necessarily anything to do with your representation of numbers. I say if your adder is built with op-amps and multiple lines, it’s doing analog computation on digits, and it stays analog for longer than if you build it with CMOS gates. This distinction is important when you start making signal integrators or matrix multipliers or do other computations with analog components, for example.
    - corethree 3y ago
      >Depends on how you define “digital” Dude, I don't define "digital"... the ENGLISH language defines the word. Read my other reply. You're confusing your made up definition of digital with the one defined by English. You're just reinventing a digital computer with parallel data lines and not using binary. It's not even getting around to the "fuzzy" part of what it means to be an "analog computer." It's just a misunderstanding on your part.
      - dahart 3y ago
        > the ENGLISH language defines the word Hehehe Huh?? English doesn’t define itself, people define words by how they’re used. Okay so if you want to make the case for the English definition, let’s see… Digital 1. of, relating to, or utilizing devices constructed or working by the methods or principles of electronics : ELECTRONIC digital devices/technology also : characterized by electronic and especially computerized technology the digital age 3: providing a readout in numerical digits a digital voltmeter a digital watch/clock 6: of or relating to the fingers or toes Okay, got it, anything electronic or anything with fingers & toes. Sounds like all analog electronic circuitry passes for digital according to the English language. :) I mean that’s actually true, most people do use “digital” as synonymous with “electronic”. That is why this definition is the first one: it’s the most used and de-facto the most correct, because that’s how the English language works, but you obviously know that already. Also sounds like the THAT computer in the article is defined as digital, because it has a digital readout, bonus! You should write to the IEEE and Anabrid corporation to have them correct their titles. https://www.merriam-webster.com/dictionary/digital https://www.merriam-webster.com/dictionary/digital I wasn’t really intending to talk about how to define the word digital, even though I see that’s what the sentence literally suggests out of context. I was trying to repeat the same thing I said earlier with slightly different words. I was talking about where you draw the line between analog and digital in order to summarize any given device as being one or the other, when in fact many devices are mixed. I’m not contradicting what you’re saying about digital (conversely, you’re not contradicting me either). Here’s an example of research into purely analog computation with parallel data lines for the purpose of increasing precision, exactly what I was talking about and it has at least one name: residue number system. https://arxiv.org/abs/2306.09481 https://arxiv.org/abs/2306.09481 If you slowed down a little instead of making so many assumptions and attacking, we could have a productive conversation. You’re misunderstanding me and stating things in binary terms it comes to analog or digital, and still not acknowledging or understanding that there is a lot of space between fully analog and fully digital, and a spectrum of cross-over points and hybrids.

dahart 3y ago

A function “call” is a software abstraction. What you’re calling a function call by defining it as stack based is a pure software abstraction. A stack is one way to implement functions, but not the only way. Capacitors can provide analog immediate access memory. Analog delay lines and feedback circuits can provide conceptually recursive functions, and those are common in analog circuits today. It’s true that analog has limited precision, though no reason you can’t represent higher precision via multiple analog signals, just like how digital requires more bits. All the rest of it still looks to me like you’re making some incorrect assumptions about what’s possible with analog circuitry.

corethree 3y ago
A function call is indeed a software abstraction. Outside of software nobody "calls" functions at all. That was my entire point. In mathematics you have function application which is close to the idea of the function call. And this idea also doesn't exist in analog computing. Ironically, Mathematics does model what's going on in an analog computer on a field called signal processing. In signal processing it's called a transform. >It’s true that analog has limited precision, though no reason you can’t represent higher precision via multiple analog signals, You can't. The only way to do this with multiple signals is to make each signal represent a digit or a portion of digits of the final value. But if you did this you'd be going digital. You likely won't be doing binary but it's still digital.
- dahart 3y ago
  > You can’t Speak for yourself. ;) Depends on how you define “digital”. Digital is typically defined as being based on logic gates, not necessarily anything to do with your representation of numbers. I say if your adder is built with op-amps and multiple lines, it’s doing analog computation on digits, and it stays analog for longer than if you build it with CMOS gates. This distinction is important when you start making signal integrators or matrix multipliers or do other computations with analog components, for example.
  - corethree 3y ago
    >Depends on how you define “digital” Dude, I don't define "digital"... the ENGLISH language defines the word. Read my other reply. You're confusing your made up definition of digital with the one defined by English. You're just reinventing a digital computer with parallel data lines and not using binary. It's not even getting around to the "fuzzy" part of what it means to be an "analog computer." It's just a misunderstanding on your part.
    - dahart 3y ago
      > the ENGLISH language defines the word Hehehe Huh?? English doesn’t define itself, people define words by how they’re used. Okay so if you want to make the case for the English definition, let’s see… Digital 1. of, relating to, or utilizing devices constructed or working by the methods or principles of electronics : ELECTRONIC digital devices/technology also : characterized by electronic and especially computerized technology the digital age 3: providing a readout in numerical digits a digital voltmeter a digital watch/clock 6: of or relating to the fingers or toes Okay, got it, anything electronic or anything with fingers & toes. Sounds like all analog electronic circuitry passes for digital according to the English language. :) I mean that’s actually true, most people do use “digital” as synonymous with “electronic”. That is why this definition is the first one: it’s the most used and de-facto the most correct, because that’s how the English language works, but you obviously know that already. Also sounds like the THAT computer in the article is defined as digital, because it has a digital readout, bonus! You should write to the IEEE and Anabrid corporation to have them correct their titles. https://www.merriam-webster.com/dictionary/digital https://www.merriam-webster.com/dictionary/digital I wasn’t really intending to talk about how to define the word digital, even though I see that’s what the sentence literally suggests out of context. I was trying to repeat the same thing I said earlier with slightly different words. I was talking about where you draw the line between analog and digital in order to summarize any given device as being one or the other, when in fact many devices are mixed. I’m not contradicting what you’re saying about digital (conversely, you’re not contradicting me either). Here’s an example of research into purely analog computation with parallel data lines for the purpose of increasing precision, exactly what I was talking about and it has at least one name: residue number system. https://arxiv.org/abs/2306.09481 https://arxiv.org/abs/2306.09481 If you slowed down a little instead of making so many assumptions and attacking, we could have a productive conversation. You’re misunderstanding me and stating things in binary terms it comes to analog or digital, and still not acknowledging or understanding that there is a lot of space between fully analog and fully digital, and a spectrum of cross-over points and hybrids.