[EM] Floyd Algorithm?

[MIKE OSSIPOFF]

Either Markus or Craig Carey, I'm not quite sure which, said:

>However, Mike Ossipoff always describes the Floyd algorithm as
>follows:
>
> > for i in range(N)
> > for j in range(N)
> > for k in range(N)
> >    low=min(B[A(i,j)],B[A(j,k)]
> >    if low>B[A(i,k)]
> >    B[A(i,k)]=low

Wrong. I don't call that the Floyd algorithm. I don't use that piece of 
code. It looks like it might be a tiny fraction of a Python strongests 
beatpaths program, with at least one of its lines partly erased.

I don't guarantee that it's part of anythng that I wrote, but, if it is, 
then let me explain the odd appearance of the arrays: Python, at least the 
version that I was using, doesn't have multidimensional arrays. It only has 
1-dimensional arrays. So I wrote a function to convert a 2-dimensional array 
position to a 1-dimensional array position. I called that function "A(i,j)". 
That 1-dimensional array position serves as the index variable for the 
strongest beatpaths array, B[A(i,j)].

The algorithm that I'll post, however, isn't written in any particular 
programming language. That will be posted within an hour or a half hour.

I do call a certain strongest beatpaths algorithm the Floyd algorithm, only 
because someone on this list told us that that's what that algorithm is 
called.

I've certainly never called it a shortest paths algorithm. It's purpose is 
to find the _strongest_ beatpath from each candidate to each other 
candidate. The strongest beatpath from Smith to Jones could also be the 
longest one. I have no idea what you're talking about when you refer to the 
shortest paths algorithm. Perhaps you're talking about a different algorithm 
from the strongest beatpaths algorithm.

The algorithm that I use was suggested by Steve Eppley. Apparently someone 
before him had described it. I don't claim to know what its official name 
is.

It's part of the algorithm that I send people for counting BeatpathWinner. 
I'll post that BeatpathWinner algorithm here in a few minutes.

Mike

_________________________________________________________________
Enjoy the holiday season with great tips from MSN.  
http://special.msn.com/network/happyholidays.armx