void operator()(const segment_type& _a, const linestring_type& _b, output_type& _out, JUNCTION _j)
{
if (_b.empty())
{
_out.push_back(_a.front());
_out.push_back(_a.back());
return;
}
_out.push_back(_a.front());
_j(_a,_b,_out);
_out.insert(_out.end(),_a.begin()+1,_a.end());
}
Arrangement
segment_cost_characterization( const segment_type & segment )
{
/* obtain the level supports of F */
double zerocost = 0. ; // cost of a matching with "zero assistance"
map<int, double> level_support ;
{
int level = 0 ;
segment_type::const_iterator lbound, rbound ;
for ( rbound = segment.begin(), lbound = rbound++ ;
rbound != segment.end() ; lbound++, rbound++ )
{
double y1, y2, len ;
y1 = lbound->first, y2 = rbound->first, len = y2 - y1 ;
const place_data & temp = lbound->second ;
level += temp.P_indices.size() - temp.Q_indices.size() ;
zerocost += len * abs( level ) ;
level_support[level] += len ;
}
}
cout << "supports " << level_support << endl ;
/* create a linear arrangement from level supports */
Arrangement value_arr ;
//int numlevels = level_support.size() ;
//list<vertex_struct> vertex_data ;
//list<interval_struct> interval_data ;
double length = 0. ;
for ( map<int,double>::iterator
it = level_support.begin() ; it != level_support.end() ; ++it )
{
int f = it->first ;
double supp = it->second ;
Arrangement::Vertex & v = value_arr.insert( f ) ;
v.local_data.support = supp ;
length += supp ;
}
// about to traverse the arrangement
Arrangement::Vertex * v_left = & value_arr.vertices.begin()->second ;
Arrangement::Vertex * v_zero ;
Arrangement::Interval * I_left = & *v_left->left ;
// some initialization
//interval_data.push_front( interval_struct() ) ;
I_left->local_data.slope = length ; // length won't compile...
Arrangement::Vertex * v_curr ;
Arrangement::Interval * I_curr ;
// traverse left-to-right to compute slopes
{
double slope = I_left->local_data.slope ;
v_curr = v_left ;
while ( true )
{
if ( (int) v_curr->y == 0 ) v_zero = v_curr ; // remember the zero vertex, plox
I_curr = & *v_curr->right ;
slope -= 2 * v_curr->local_data.support ;
I_curr->local_data.slope = slope ;
if ( I_curr->right == NULL ) break ;
v_curr = I_curr->right ;
}
}
// traverse zero-to-left, then zero-to-right, to obtain offsets
{
double offset = zerocost ;
v_curr = v_zero ;
while ( true )
{
I_curr = & *v_curr->left ;
I_curr->local_data.offset = offset ;
offset -= I_curr->local_data.slope * I_curr->length() ; // subtract, since negative direction
if ( I_curr->left == NULL ) break ;
v_curr = I_curr->left ;
}
}
{
double offset = zerocost ;
v_curr = v_zero ;
while ( true )
{
I_curr = & *v_curr->right ;
I_curr->local_data.offset = offset ;
offset += I_curr->local_data.slope * I_curr->length() ; // add, since positive direction
if ( I_curr->right == NULL ) break ;
v_curr = I_curr->right ;
}
}
return value_arr ;
}