Hello,

Is anyone familiar with a mathematical algorithm called "erlang" ?  It is
used for 'best fit' computations.  I would like to find more info about this
but haven't had any luck.  Any information which might help me locate more
information about this topic would be appreciated!

Thanks,

Mitch
------------------------------------------------
 [Ritch]

Mitch -

See Arnold Allen's "Probability, Statistics and Queueing Theory" (Academic
Press), for one.

According to Allen, A. K. Erlang was a Danish mathematician who studied
delays in telephone traffic (and thus the kind of problem faced by computer
performance people and also the folks who decide how many booths to put in
a turnpike toll plaza).  The Erlang-k formula is actually a set of
probability distributions where the expected value of the mean is (1/L)
and the expected value of the variance is (1/kL^2) (so you look at your
data to see which value of k to use).  The formula is

f(x) = 0 if x<=0,
      = [Lk(Lkx)^(k-1)exp(Lkx)]/(k-1)!

The curve for k=1 is an exponential decay from f(0)=1.  The curves for k>1
all start at f(0)=0 and show a single peak, but the peak position and
symmetry vary with k.

Erlang also provided solutions for several other classes of queueing systems,
and the equations for some of those solutions bear his name.

Hope this is what you're looking for.

- Rich
------------------------------------------------
Qualcosa sulle distribuzioni di Erlang si trova anche in 2031 Fisz,
pag. 344-351, e in 909 Fahrmeir/Kaufmann/Ost, pag. 130-131. 
Nel 1948 e' uscito un libro dal titolo "The life and work of A.K. Erlang",
scritto dallo stesso Erlang (?).