Notices by ∑ XahLee (xahlee@noagendasocial.com), page 100

respect #Math http://xahlee.info/math/fibonaci_spiral_hurricane.html

@Xil can code can math?

about fibo sequence, basically anything on the web about it is trash. Unless it's from a professional math site, or Wikipedia.

Fibonaci sequence is one of those math things, that tries to make math attractive on drugs.

Math Mysticism: is Hurricane Shape a Fibonaci Spiral?
http://xahlee.info/math/fibonaci_spiral_hurricane.html

this one, features driverless programing of keys http://xahlee.info/kbd/keyboard_no_numpad.html

word on the psy street is that read this book and you'll get all the chicks you want http://amzn.to/2gWpKfN

Learn #Python in 1 Hour http://xahlee.info/python/python_basics.html

ask me questions on patreon https://www.patreon.com/posts/15161253 #emacs #keyboard

every time emacs lisp runs (say, for a 3 min file access heavy script), it semi-freezes the whole OS. On linux and Mac too.

understand #clojure partial (currying), comp (function composition), apply, memorize, in 10 minutes!
http://xahlee.info/clojure/clojure_function_currying.html

emacs on Mac! my recent happenings. Xah Emacs Blog http://ergoemacs.org/emacs/blog.html

Leopold FC660C, this is the most popular replacement for happy hacking keyboard http://xahlee.info/kbd/leopold_fc660c_keyboard.html

@Xil it's easy to write such function. try it. The hard part is how to write it so it's efficient. (cpu time and memory space) and how to code it so it's elegant. (this is where language's features will shine thru.)

@Xil for example, factorial function, or fibonaci sequence. In math it happens often. check out “logistic map” or “iterated function system” or “dynamical systems”

6 some lang, (Mathematica, haskell), can define f(1) and f(n) separately. So, no chicken n egg recursive definition problem.

7 actually chicken n egg recursive definition problem remain. With respect to order of evaluation.

4 in math, nth term is defined by previous term, and f[1] is defined non-recursively. so, it's well defined. In a sense, no “recursion”

5 in most programing langs, body of recursive f use “if” to check input. So, “no recursion” really. But chicken n egg remain in defining f.

xah edu corner extempore! episode №20171101042745, ban recursion in programing languages

1 with regards to computer science, recursion should be ban'd in programing languages.

2 it's got the chicken n egg problem: before it's defined, it's calling itself. Like russell's paradox, or 1st order logic in twilight zone

3 But in math, we have recursive relation, and comp sci recursive theory. How to resolve that?

😂 who's this xah lee? Google search, click, then wham, your computer is now infested with virus. lol

these are automated spam systems. They generate page by monitoring global site ranking. The more popular is your site, the more hits by them.

since few months ago, every day, there's 5 to 10 new spam sites containing my name. Each proclaims “By Xah Lee” of scraped stuff. lol.

Quiz. write a function r(f,x,n) that returns a list [f(x), f(f(x)), ...], length n. write in your fav lang.

f is function (e.g. f(x) = x+1), x is a number, n is a number ≥ 1. we want [f(x), f(f(x)), ...]

#haskell #javascript #golang #clojure

quiz. write a function recurseList(f,x,n) that returst a list, [f(x), f(f(x)), ...], length n.
write in your fav lang.
# haskell #javascript #golang