[comp.misc] mathematical tricks

jjw@palladium.UUCP (John J. Wallace) (07/27/88)

A few years back, a professional computer journal published an article
full of mathematical one-liners, such as "to round down to a power of
two, do this," "to find the first one, do this," etc.  I think this was
Communications of the ACM around 1985, but I'm not sure, and I can't
find it in *my* archives.

Any help?  When I find this, I will post it on my wall!
-- 
John J. Wallace
Epoch Systems, Inc., 313 Boston Post Rd. West, Marlborough, MA 01752
...!linus!alliant!palladium!jjw -or- ...!harvard!cfisun!palladium!jjw
(617)481-3717

baum@Apple.COM (Allen J. Baum) (07/29/88)

[]
>In article <547@palladium.UUCP> jjw@palladium.UUCP (John J. Wallace) writes:
>A few years back, a professional computer journal published an article
>full of mathematical one-liners, such as "to round down to a power of
>two, do this," "to find the first one, do this," etc.  I think this was
>Communications of the ACM around 1985, but I'm not sure, and I can't
>find it in *my* archives.
>
>Any help?  When I find this, I will post it on my wall!
 This sounds a lot like the MIT AI Labs "Hakmem" memo. I used to have a
copy, but I think it was borrowed. Out of print, too, I believe. Full of
neat tricks.


--
{decwrl,hplabs,ihnp4}!nsc!apple!baum		(408)973-3385

davy@ea.ecn.purdue.edu (Dave Curry) (07/29/88)

In article <14878@apple.Apple.COM> baum@apple.UUCP (Allen Baum) writes:
>[]
>>In article <547@palladium.UUCP> jjw@palladium.UUCP (John J. Wallace) writes:
>>A few years back, a professional computer journal published an article
>>full of mathematical one-liners, such as "to round down to a power of
>>two, do this," "to find the first one, do this," etc.
	[etc...]
> This sounds a lot like the MIT AI Labs "Hakmem" memo. I used to have a
>copy, but I think it was borrowed. Out of print, too, I believe. Full of
>neat tricks.

HAKMEM is not out of print; at least it wasn't last year when I ordered
my copy.  Send $3.50 to:

	Artificial Intelligence Laboratory
	Massachussetts Institute of Technology
	545 Technology Square
	Cambridge, MA 02139

Ask for a copy of AI Memo #239, "HAKMEM".

There's all sorts of useful and interesting stuff in here, and also lots
of relatively useless (outdated) stuff.  But it makes fascinating reading
anyway.

--Dave Curry

bturner@hpcvlx.HP.COM (Bill Turner) (07/30/88)

One issue of the Communications of the ACM (I can't remember which one, it
was about 1-2 years back) had a number of "rules of thumb" for CS.  It 
included some that I still remember (particularly two from Grace Hopper:
pi seconds is a nanocentury, and a nanosecond is about 1 foot [distance
light travels])

(I'd be more helpful if I had my CACM's unboxed...)

--Bill Turner