Big O notation.

[OwlHoot]

Thanks all of you.

Can I ask then....if you're multiplying 2 numbers...

why is it O(n^2) and not O(n*m)?

Does it not matter that the 2 numbers which we're multiplying are not the same? Does n simply mean "input"?

because the product of two numbers is at most the square of the largest. So as the O notation represents an upper bound you may as well use the square (that and the fact that you then express it in terms of one "variable").

BTW, you can multiply two numbers of size n (upper bound on both) in O(n.log(n)) by using a fast Fourier transform

P.S. What does "get a word" mean?

[NotAllThere]

You might see ^ written as ** , just to confuse matters.

[SallyAnne]

because the product of two numbers is at most the square of the largest.

Ahhhhhh!!!!!!! I see!!!!!

The light goes on!!!!!

Owlhoot - you've always been my favourite

P.S. What does "get a word" mean?

"have a word with yourself"....meant lovingly, as your previous post had been so advanced it'd made my head actually explode.



many many thanks, and to everyone else too x x x

[DaveB]

In the proper FORTRAN notation...

If you can find it in amongst all the declarations and assorted bagage in your typical Fortran code