christianmlongApr 18, 2023
Mike Spooner

Quote from the FORTRAN manual for Xerox computers:

"The primary purpose of the DATA statement is to give names to constants; instead of referring to pi as 3.141592653589793 at every appearance, the variable PI can be given that value with a DATA statement and used instead of the longer form of the constant. This also simplifies modifying the program, should the value of pi change."

Apr 17, 2023 at 12:48pmWeb
Show threadGottfried Szing Apr 17, 2023

@shelldozer Oh yes, happens all the time that PI changes. 😆

https://media.ccc.de/v/mch2022-236-non-euclidean-doom-what-happens-to-a-game-when-pi-is-not-3-14159-

Non-Euclidean Doom: what happens to a game when pi is not 3.14159…

media.ccc.de
Show threadarclightApr 17, 2023
@shelldozer Ironically, the value of PI is much more likely to change if your code doesn't use named constants. A hallmark of most scientific software is the inconsistent precision applied to well-known physical and numerical constants. You're likely to find literal values of ln(2), g, and π written in at least 3 different precisions through a code.
Show threadarclightApr 17, 2023
@shelldozer Want to drive lazy scientists and engineers nuts? Require citation to the canonical source of every physical constant used in a code.
"What?! Everyone knows g is 9.8 m/s2"
"Then it should be trivial to provide a reference (points at most recent CODATA release on NIST website)"
"(Angry typing) FINE. Happy now?"
"Nice. Now do Boltzmann's constant and every other constant whose value you just pulled out of your ass in this code..."
Show threadMike SpoonerApr 17, 2023
@arclight Although, pedantically, such cases are really just *different* *constants*.
Show threadToken Sane PersonApr 17, 2023

@shelldozer @arclight

"One man's constant is another man's variable." Alan Perlis.

Osborn's Law: Constants aren't, variables don't.

(with apologies for the implicit sexism that was the norm in 1982)

Show thread𝐊𝐢𝐧𝐠𝐮 Apr 17, 2023

@shelldozer

Let's change the value of pi!!

Show threadRupert ReynoldsApr 17, 2023
@kingu @shelldozer
It's been tried :-)
(Indiana Pi bill 1897)
Show threadEdmund SchweppeApr 17, 2023
@shelldozer Legislatures are infamous for pulling stunts that coders have to adjust for. https://www.smithsonianmag.com/science-nature/indiana-almost-made-pi-equal-32-and-other-pi-day-facts-180954521/
Indiana Almost Made Pi Equal to 3.2, and Other Pi Day Facts

As you celebrate the mathematical holiday, here's a history of notable moments in the irrational number's past

Smithsonian Magazine
Show threadCromleyApr 17, 2023
@shelldozer *eyes pi suspiciously
Show threadStewart RussellApr 21, 2023
@shelldozer In certain old IBM FORTRAN versions, it's possible to redefine constants. Redefining 1 to be equivalent to the value of 2 can be quite hilarious