14 Matching Annotations
  1. Mar 2021
  2. Feb 2021
    1. 17.3. Fixed point

      QUESTION: What is a fixed-point of a function?

      ANSWER: See this video) at least, and the Fixed-point (mathematics)) wikipedia article:

      In mathematics, a fixed point (sometimes shortened to fixpoint, also known as an invariant point) of a function is an element of the function's domain that is mapped to itself by the function. That is to say, c is a fixed point of the function f if f(c) = c. This means

      f(f(...f(c)...)) = f n(c) = c
      

      an important terminating consideration when recursively computing f. A set of fixed points is sometimes called a fixed set.

      For example, if f is defined on the real numbers by f(x)=x^{2}-3x+4,}, then 2 is a fixed point of f, because f(2) = 2.

      There is also the wiki article fixed-point combinator that actually plays a role here, but read through the articles in this order.

      Then dissect the Stackoverflow thread What is a Y combinator?, and pay attention to the comments! For example:

      According to Mike Vanier's description, your definition for Y is actually not a combinator because it's recursive. Under "Eliminating (most) explicit recursion (lazy version)" he has the lazy scheme equivalent of your C# code but explains in point 2: "It is not a combinator, because the Y in the body of the definition is a free variable which is only bound once the definition is complete..." I think the cool thing about Y-combinators is that they produce recursion by evaluating the fixed-point of a function. In this way, they don't need explicit recursion. – GrantJ Jul 18 '11 at 0:02

      (wut?)

      Other resources in no particular order:


      QUESTION: How the hell did they come up with the idea of using this with Nix and package management? (..and who? I remember a video saved somewhere, but maybe that was about overlays)


      QUESTION: ... and how does it work in this context?

      ANSWER: Well, not an answer yet, but this may be something in the right direction:

      http://blog.tpleyer.de/posts/2020-01-29-Nix-overlay-evaluation-example.html

  3. Sep 2020
  4. Aug 2020
  5. Apr 2020
  6. Dec 2019
    1. Unlike similar tools that are scheduled to take backups at a fixed time of the day, Timeshift is designed to run once every hour and take snapshots only when a snapshot is due. This is more suitable for desktop users who keep their laptops and desktops switched on for few hours daily. Scheduling snapshots at a fixed time on such users will result in missed backups since the system may not be running when the snapshot is scheduled to run. By running once every hour and creating snapshots when due, Timeshift ensures that backups are not missed.
  7. Oct 2019
    1. fixed-point

      "fixed-point", "fix point" seems to be most important concept in Nix, because overrides, overridePackages, overlays are built using it.

  8. Sep 2019
  9. Oct 2016
    1. This model of microservices that register themselves to a global registry will have a lot of advantages when it comes to building one or multiple applications using a microservice architectural approach. Eureka on its own won't have that much of use, but as you'll see in the future blogposts, Eureka will be the key element to locate all of our microservices.

      How to use Eureka locate our microservices?

      all Eureka clients register itself in the register center(Eureka Server)