From: Brook Milligan (brook_at_[hidden])
Date: 2007-09-19 09:37:53
Andrew Sutton writes:
> I mostly agree, but I think we can do better too. One of the reasons
> that it probably took the name distance_zero() is that there haven't
> been many motivating examples of non-additive combinations of
> distance (and hence identities).
I suspect that you are right in that regard as most mathematical
algorithms are specified in terms of summations. However, I ran into
the more general case when I tried to develop generic graph-based
algorithms for probability models, which require products. There is
one example included in the probability library I have developed,
which is described at:
http://biology.nmsu.edu/software/probability/
> I'm wondering if it might not be worthwhile to build simple
> structures that provide the function types and constants for these
> algorithms rather than specifying them as distinct parameters. For
> the common case, these would simply default to the basic additive
> operations and identities but could be easily overridden.
By this I take it that you mean something along the lines of
std:limits<> that defines various properties of the type? That would
certainly better integrate the concepts and simplify the graph
algorithm interfaces.
Cheers,
Brook