• blakestacey@awful.systemsMEnglish
    0·
    11 months ago

    Taking a look at Super-recursive algorithm, and wow…

    Examples of super-recursive algorithms include […] evolutionary computers, which use DNA to produce the value of a function

    This reads like early-1990s conference proceedings out of the Santa Fe Institute, as seen through bong water. (There’s a very specific kind of weird, which I can best describe as “physicists have just discovered that the subject of information theory exists”. Wolfram’s A New Kind[-]Of Science was a late-arriving example of it.)

    • V0ldek@awful.systemsEnglish
      0·
      11 months ago

      In computability theory, super-recursive algorithms are a generalization of ordinary algorithms that are more powerful, that is, compute more than Turing machines[citation needed]

      This is literally the first sentence of the article, and it has a citation needed.

      You can tell it’s crankery solely based on the fact that the “definition” section contains zero math. Compare it to the definition section of an actual Turing machine.

      • blakestacey@awful.systemsMEnglish
        0·
        11 months ago

        More from the “super-recursive algorithm” page:

        Traditional Turing machines with a write-only output tape cannot edit their previous outputs; generalized Turing machines, according to Jürgen Schmidhuber, can edit their output tape as well as their work tape.

        … the Hell?

        I’m not sure what that page is trying to say, but it sounds like someone got Turing machines confused with pushdown automata.

        • self@awful.systemsMEnglish
          1·
          11 months ago

          it’s hard to determine exactly what the author’s talking about most of the time, but a lot of the special properties they claim for inductive Turing machines and super-recursive algorithms appear to be just ordinary von Neumann model shit? also, they seem to be rather taken with the idea that you can modify and extend a Turing machine, but that’s not magic — it’s how I was taught the theoretical foundations for a bunch of CS concepts, like nondeterministic Turing machines and their relationship to NP-complete problems

        • V0ldek@awful.systemsEnglish
          1·
          11 months ago

          That’s plainly false btw. The model of a Turing machine with a write-only output tape is fully equivalent to the one where you have a read-write output tape. You prove that as a student in elementary computation theory.

          • aio@awful.systemsEnglish
            1·
            11 months ago

            The article is very poorly written, but here’s an explanation of what they’re saying. An “inductive Turing machine” is a Turing machine which is allowed to run forever, but for each cell of the output tape there eventually comes a time after which it never modifies that cell again. We consider the machine’s output to be the sequence of eventual limiting values of the cells. Such a machine is strictly more powerful than Turing machines in that it can compute more functions than just recursive ones. In fact it’s an easy exercise to show that a function is computable by such a machine iff it is “limit computable”, meaning it is the pointwise limit of a sequence of recursive functions. Limit computable functions have been well studied in mainstream computer science, whereas “inductive Turing machines” seem to mostly be used by people who want to have weird pointless arguments about the Church-Turing thesis.