From: jsiek_at_[hidden]
Date: 2000-01-27 00:46:50
Dave Abrahams writes:
> > Or with g++, even if you don't do a "using anmespace std;", the
> > conflict still happens :( The only way to avoid it would be to say
> > set() has to be in boost, and always do boost::set(), which is
> > a bit nasty.
>
> What is nasty about that?
Well, it means *everyone* has to put their property accessors in
namespace boost, and it clutters up your algorithm code. It
was bad enough moving away from operator[] to set/get, but
boost::set, boost::get is even worse! Check out the following
algorithm, which version is more readable?
On a side note, checkout how cool the expression-template'd
functors work in this example :)
template <class F, class PredGraph, class In, class Out>
void
iterate_flow_forward( const F& f,
const PredGraph& blocks,
In in,
Out out )
{
typename graph_traits<PredGraph>::adjacency_iterator p, pend;
typedef typename std::iterator_traits<In>::value_type Set;
bool change;
int B;
do {
change = false;
for (B = 0; B < num_vertices(blocks); ++B) {
tie(p, pend) = inv_adj(B, blocks);
boost::set(in, B, accumulate(p, pend, Set(),
identity<Set>() + indirect(out)));
Set old_out = boost::get(out, B);
boost::set(out, B, f(B, boost::get(in, B)));
if (boost::get(out, B) != old_out)
change = true;
}
} while (change);
}
template <class F, class PredGraph, class In, class Out>
void
iterate_flow_forward( const F& f,
const PredGraph& blocks,
In in,
Out out )
{
typename graph_traits<PredGraph>::adjacency_iterator p, pend;
typedef typename std::iterator_traits<In>::value_type Set;
bool change;
int B;
do {
change = false;
for (B = 0; B < num_vertices(blocks); ++B) {
tie(p, pend) = inv_adj(B, blocks);
in[B] = accumulate(p, pend, Set(), identity<Set>() + indirect(out));
Set old_out = out[B];
out[B] = f(B, in[B]);
if (out[B] != old_out)
change = true;
}
} while (change);
}