Man or boy test | Hacker News Reader

Man or boy test

en.wikipedia.org

148 pointslisper61 comments

I am about a third of the way through Knuth’s Art of Computer Programming. It is an amazing piece of work created by one man. The sheer breadth and level of complexity in the work is awe inspiring. I wish my younger self had read a copy when learning 6502 assembly in the 80s simply to understand data (information) structures.

That said, this procedure is a doozy. It reminds me of the Ackermann function but doesn't quite grow as fast (understatement).

If you like the Ackerman function you're gonna love Kruskal's tree theorem.

https://en.wikipedia.org/wiki/Kruskal%27s_tree_theorem

This essay is also great if you like this kind of thing: https://www.scottaaronson.com/writings/bignumbers.html

Or this page [1] on large numbers.

[1] https://mrob.com/pub/math/largenum.html

Or Friedman’s SSCG function.

> "SSCG(3) is much, much larger than both TREE(3) and TREE^(TREE(3))(3) (the TREE function nested TREE(3) times with 3 at the bottom)"

Holy freakin' cow.

And the busy beaver sequence grows faster than that.

My mind is well and truly boggled.

I'm not strong on mathematics but I've been able to enjoy the historical overview and references. I agree with you on how amazing the work is.

I've read the wiki page and still don't get what the big deal is about the ackermann function. Can someone explain? TIA

The RosettaCode versions:

http://rosettacode.org/wiki/Man_or_boy_test

"Haskell

Haskell is a pure language, so the impure effects of updating k must be wrapped in the IO or ST monad (...)

On an AMD Opteron 6282 SE (1) using GHC 7.8.2 this program can compute k = 30 in 1064 s and 156.2 GiB. (2)"

"JavaScript

In Chrome we get a "Maximum call stack size exceeded" when a > 13. In Firefox we get "too much recursion" when a > 12." (Note: it should say "k" (the parameter) not "a").

---

1) 16 cores.

2) 156 GB of RAM: "159874 MB total memory in use"

I'm not super familiar with Algol but it seems that this function is not using call-by-value? In most of the translations the parameters to A are functions instead of reals.

Is this call by name or call by reference? And how would call by value look like in Algol?

Call by name.

Do you know if there a way to specify that a parameter should be passed using call-by-value?

Function parameters can be declared ‘value’.

When I saw the title I thought, huh, maybe it's that thing were old prisoners threaten the young ones to see who's easy prey but no - it's a test in Algo 60 to see what compilers correctly implement recursion.

I thought it was going to be about rituals present in many cultures around the world (especially before contact with modern technological civilization) - the rites of passage from childhood to adulthood.

I was interested to know if I thought I could pass such a ritual. And then I was interested to know if I thought it was important for me to pass :-) Not sure I know the answer to that last one!

I think the answer to the last one depends on your social circle :). Rites of passage are group membership rituals. There's no point in doing the movements and sacrifices if there's no group you wish to enter that uses it as a condition of membership.

This is a super good point. I keep going on about how in Japan (where I live) it is super important to be willing to do the things that are required when trying to move to an in-group. You can't generally pick and choose ("I'll follow the rules that makes sense to me" doesn't fly here). So, you have put your finger on it. I would definitely do that if I valued the in-group I was trying to move to.

You seem to be under the impression that somebody would say "I'll follow the rules that make sense to me" when entering a new group and suffer no negative social concequences in other societies.

I really don't think picking and choosing which rules you follow would be appreciated anywhere.

Very curious, can you give a few examples of these rules?

Joseph Campbell argues that the stages of human development are the same as they were in ancient times, and so your brain still responds to the same symbolic gestures your ancestors would encounter during their transition from boyhood to manhood.

If you’re having trouble transitioning from one stage to the next, Campbell claims it can help to look at the rites of passage present in ancient myths. One example is changing your mode of dress to usher in a life transition. By purposefully introducing these symbolic gestures into your own life, you can tap into the pathway of maturity that exists within your subconscious.

I don’t want to be part of any group that would accept me as a member.

Men know this reference and find it funny. Boys don’t. //smiley_face

http://antglove.com/

I thought it was about the test where children reach with their right hand over their head to touch the left ear - a common tongue-in-cheek test for first grade readiness.

Apparently the test has some real foundation. That the proportion of the limbs (and relative size of the head) only allows children to touch the ear at about 5 years old.

Of course it is in the Online Encyclopedia of Integer Sequences: https://oeis.org/A132343

Knuth also wrote the "trip" and "trap" suites for TeX and MetaFont conformance.

https://texfaq.org/FAQ-triptrap

...and girls from gals

Reply on news.ycombinator.com