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# sorting performance - need help with math

Ranch Hand
Posts: 4716
9
im doing research on sorting algorithms. i have 2 articles about radix sort. one says radix sort is O(n), in other words linear. the other says it is only linear if the wordsize of the computer(32 or 64 nowadays) is >= log n, otherwize it its O(n log n). isnt log 1,000,000 only 6?
even if they mean log base 2, 2^32 is a huge number
ps: the second article introduces an algorithm with O(n log log n)
[ April 18, 2004: Message edited by: Randall Twede ]

blacksmith
Posts: 1332
2

Originally posted by Randall Twede:
even if they mean log base 2, 2^32 is a huge number

However, some people deal with data sets larger than that.

Randall Twede
Ranch Hand
Posts: 4716
9
ok, so for normal folks it would be linear. i get the idea though.
im really getting into this research, it's cool!
i should have known it was base 2 but i think in my paper i use subscript to make it clear
[ April 18, 2004: Message edited by: Randall Twede ]

Sheriff
Posts: 7023
Side note, lg is a common representation for log base 2.

Ranch Hand
Posts: 5093
another note: log is used to mean base 2 in all applications except computing (for some reason) unless a base is specified.
log base e is generally written as ln.
So possibly the authors meant log base 2.

Wanderer
Posts: 18671
Um, in applications outside computing, log usually means base 10. In my experience at least. Perhaps it's different in Europe? I doubt it - outside of computing, base 2 just isn't as useful to most people as base 10 is. Errr, was. The main motivation for using logs was as a faster replacement for multiplication, back in the dark ages before calculators and computers. This is easiest if you use logs base 10, to match our number system.

lowercase baba
Posts: 12871
62
As a former math teacher, log always meant base 10. And Jim, it still is quite relevant - It's how my slide rule works. You know what a slide rule is, right?

Jim Yingst
Wanderer
Posts: 18671
Sure. I found an old one once, wouldn't rest until I'd figured out how to use it. (Including the trig functions). Never actually used it in real life though.

Jeroen Wenting
Ranch Hand
Posts: 5093
sorry, meant base 10

 Consider Paul's rocket mass heater.