On 01/20/2011 12:34 AM, Andre Poenitz wrote:
On Thu, Jan 20, 2011 at 06:00:27AM +0100, Peter Kümmel wrote:
Rich, you know the Graph code much better than me. Is it possible to have
real const functions to get pathes, or it is necessary to always set
the visited flag in vertices_. Couldn't the calculation be done in one
function call which then would be more expensive as consequence.
It's not needed, it's just a consequence of the current implementation
IIRC. The 'visited' information should not be part of the 'static' data
of the graph, but rather a separate temporary structure that's passed
around as separate parameter.
Unfortunately, we seem to use this as if it were static. This is why
there is the clear_visited boolean that gets passed into routines like
getReachable(). See e.g. Converters::importableFormats(). Perhaps this
is just some kind of optimization that could be removed? It would be
less of an issue if the importableFormats were cached. I don't myself
see why we shouldn't do that. We must decide what formats we can import
over and over and over....
Richard
