// -*- C++ -*-
namespace Kite {
/*! \class TrackSegmentCost
* \brief The cost calculator of a TrackSegment.
*
* \section secMiscAttributes Miscellaneous attributes
*
* Net instead of \TrackSegment : what we will access the most is the
* \TrackSegment owner, so it's it we keep as an attribute. The consequence
* beeing that the update member function should be given the \TrackSegment
* as argument.
*
*
* \section secBoundInterval Bound interval cost component
*
* This is the minimal interval to which the \TrackSegment can be
* shrunk without breaking the net's connexity. The interval is
* computed by AutoSegment::getTopologicalInfos(). And the computation
* is as follow :
*
* - Each AutoContact has a constraint box which defines
* the legal area where the AutoContact could be positionned.
*
- The left bound is the minimum of all constraints
* boxes max.
*
- Conversely, the right bound is the maximum of all
* constraints boxes min.
*
* \image html TrackSegmentCost-1.png "Left bound & right bound"
* \image latex TrackSegmentCost-1.pdf "Left bound & right bound" width=0.6\textwidth
*
* \image html TrackSegmentCost-2.png "Maximal shrink example"
* \image latex TrackSegmentCost-2.pdf "Maximal shrink example" width=0.6\textwidth
*
*
* \section secCostAttractors Attractors and differential wirelength cost component
*
* The goal of attractors is to compute the wirelength variation whenever
* the \TrackSegment changes of supporting \Track.
*
* The \TrackSegment is connected to perpandicular \TrackSegment, attractors
* are the extremity position of those perpandicular which are not
* connected to the reference \TrackSegment. The true rule is more complex
* an is computed by AutoSegment::isTopologicalBound().
*
* \image html TrackSegmentCost-3.png "Attractors example"
* \image latex TrackSegmentCost-3.pdf "Attractors example" width=0.6\textwidth
*
* In the attractor example, the reference horizontal \TrackSegment (in
* black) which is made of (at least) three \c AutoSegments, is connected
* to five vertical canonical \TrackSegment (labelled \e A through \e E).
*
* \e Left attractors are below the horizontal \TrackSegment axis,
* \e right ones are above. Punctual attractors are exactly on the axis.
*
* As both \TrackSegment and \c AutoSegment are orienteds, source is always
* the minimum and target always the maximum.
*
* The attractors are deduced as follow :
*
* - \e A : source is on the axis and move with it, so it is not took
* into account. Target
\@2:19 is a right attractor.
* - \e B : not aligned due to constraints on \e A, fully included in
* \e A, do not generate attractor.
*
- \e C : canonical is accross the reference horizontal, both source
* and target generate attractors :
left \@7:6 and
* right \@7:16.
* - \e D : punctual, that is null-length canonical exactly on the
* axis. Generate only one attractor :
punctual \@14:10
* (i.e. not one for each extremity).
* - \e E : target is on the axis and move with it, so it is not took
* into account. Target
\@23:4 is a left attractor.
*
* The concept of left/right and punctual flavor for attractors are only
* used dured construction. Once built only the coordinate remains.
*
* The extremity of perpandicular canonical \TrackSegment connected to
* the reference segment do not generate attractors because they move
* with it. But there are exception to this behavior : one is that
* the extremity is in fact anchored to a terminal and will not move.
* This is the work of the AutoSegment::isTopologicalBound() function
* to check for thoses exceptions, in which case an attractor will be
* created.
*
*
* \section secTerminalCount The terminal count cost component
*
* The number of terminals directly connected to this \TrackSegment.
* Computation relies on AutoSegment::getTerminalCount().
*/
/*! \function Net* TrackSegmentCost::getNet () const;
* \Return The Net owning this TrackSegment.
*/
/*! \function unsigned int TrackSegmentCost::getTerminals () const;
* \Return The number of terminal directly connected to this \TrackSegment.
*/
/*! \function DbU::Unit TrackSegmentCost::getWiringDelta ( DbU::Unit axis ) const;
* \param axis The axis where to put the TrackSegment.
*
* \return The total wirelengh needed for perpandicular TrackSegment to connect
* with this one sets on axis. The sum of distance to all the
* attractors.
*/
/*! \function void TrackSegmentCost::update ( TrackSegment* trackSegment );
* \param trackSegment the associated \TrackSegment, must be the same as used
* in the construction.
*
* Update the cost calculator after a relative position change.
*/
} // End of Kite namespace.