Plato, Church, and Turing

07/07/18 08:53 PM Filed in: Computing | Philosophy

The lambda calculus is the "platonic form" of a Turing machine

     — wrf3

I wrote this in a comment over at Edward Feser's blog in a comment to Gödel and the mechanization of thought. Google doesn't find it anywhere in this exact form, but this post appears to express the same idea. The components of this idea can be found elsewhere, but it isn't stated as directly as here.
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Ancient Publication

06/24/18 05:43 PM Filed in: Computing | Life
Dr.Dobbs.Cover
Sometime in 1987, or thereabouts, I was working with various Intel processors. For some reason I needed to know which type of CPU some code was running on, so I wrote a routine that would determine whether the processor was an 8086, 80186, 80286, or 80386 and, if a 286 or 386, whether it was running in real or protected mode. I wrote an article about it which was first printed in PC Tech Journal, November 1987, on page 51. Somewhere I still have a copy of that issue. Somewhere. The article was then anthologized in Dr. Dobb's Toolbook of 80286/80306 programming on pages 75 to 78.

The text of the article and the source code is below the fold. I wish I had my original work to show how it was edited for publication.

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Round to Nearest

05/11/18 12:10 PM Filed in: Math | Lisp
I recently had to write some code to round a value to something other than the nearest integer, e.g. rounding a measurement to the nearest 0.5 or 0.1 unit.


RoundTo
To figure out how to do it, suppose we want to round to the nearest multiple of, say, 5.


Scale the number line from 0, 5, 10, ... to 0, 1, 2, ...


Round.


Then scale from 0, 1, 2... back to 0, 5, 10...

Extension to values other than 5 is straightforward.

The Lisp code:

(defun round-to (n m)
  (if (or (null m) (zerop m))
      n
      (* (round (/ n (float m))) (float m))))


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Words of Wisdom from The Bean Tap

03/23/18 02:25 PM Filed in: Life | Quotes
This morning, at The Bean Tap:


Can't you see it? It's invisible!

     — Dylan



He’s about to slap the “old” right off your face.

     — Heather

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Hope

02/03/18 03:32 PM Filed in: Life | Philosophy | Synchronicity


During lunch today I was listening to a video featuring Jordan Peterson and Ben Shapiro. Between 16:35 and 16:52 in the video, Peterson remarks:

"Well, it's partly because the problem with … the problem with relativism let's say … let's say that did produce a radical state of equality. Well the problem with that is that there's no "up". And the problem with there being no "up" is there's no hope. And the problem with that is that people actually live on hope."

Dogs, too.

My granddog, Titan, lives by hope. Hope that he will get treats, especially after going for a walk or when I come home. Here he is, live and unrehearsed, when I arrived home from lunch. He greets me at the door to the garage, then stops where we keep his treats in a niche above his food and water bowls. As I go by, he hopes that he'll get a bit of the waffles my wife made this morning.

I can't ever disappoint my dog.

Mlem.



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