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/*=========================================================================
Program: Visualization Toolkit
Module: vtkDijkstraGraphInternals.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/**
* @class vtkDijkstraGraphInternals
* @brief Helper class due to PIMPL excess
*
* @sa
* vtkDijkstraGraphGeodesicPath
* @warning
* Do not include this file in a header file, it will break PIMPL convention
*/
#ifndef vtkDijkstraGraphInternals_h
#define vtkDijkstraGraphInternals_h
#include <vector>
#include <map>
//-----------------------------------------------------------------------------
class vtkDijkstraGraphInternals
{
public:
vtkDijkstraGraphInternals()
{
this->HeapSize = 0;
}
~vtkDijkstraGraphInternals()
{
}
// CumulativeWeights(v) current summed weight for path to vertex v.
std::vector<double> CumulativeWeights;
// Predecessors(v) predecessor of v.
std::vector<int> Predecessors;
// OpenVertices is the set of vertices which has not a shortest path yet but has a path.
// OpenVertices(v) == 1 means that vertex v is in OpenVertices.
// OpenVertices is a boolean (1/0) array.
std::vector<unsigned char> OpenVertices;
// ClosedVertices is the set of vertices with already determined shortest path
// ClosedVertices(v) == 1 means that vertex v is in ClosedVertices.
// ClosedVertices is a boolean (1/0) array.
std::vector<unsigned char> ClosedVertices;
// Adjacency representation.
std::vector< std::map< int,double > > Adjacency;
// Path repelling by assigning high costs to flagged vertices.
std::vector<unsigned char> BlockedVertices;
void Heapify(const int& i)
{
// left node
unsigned int l = i * 2;
// right node
unsigned int r = i * 2 + 1;
int smallest = -1;
// The value of element v is CumulativeWeights(v)
// the heap stores the vertex numbers
if ( l <= this->HeapSize &&
( this->CumulativeWeights[ this->Heap[l] ] <
this->CumulativeWeights[ this->Heap[i] ] ) )
{
smallest = l;
}
else
{
smallest = i;
}
if ( r <= this->HeapSize &&
( this->CumulativeWeights[ this->Heap[ r ] ] <
this->CumulativeWeights[ this->Heap[ smallest ] ] ) )
{
smallest = r;
}
if ( smallest != i )
{
int t = this->Heap[i];
this->Heap[ i ] = this->Heap[ smallest ];
// where is Heap(i)
this->HeapIndices[ this->Heap[i] ] = i;
// Heap and HeapIndices are kinda inverses
this->Heap[ smallest ] = t;
this->HeapIndices[ t ] = smallest;
this->Heapify( smallest );
}
}
void HeapInsert(const int& v)
{
if ( this->HeapSize >= (this->Heap.size() - 1) )
{
return;
}
this->HeapSize++;
int i = this->HeapSize;
while ( i > 1 &&
this->CumulativeWeights[ this->Heap[i/2] ] >
this->CumulativeWeights[v] )
{
this->Heap[ i ] = this->Heap[i/2];
this->HeapIndices[ this->Heap[i] ] = i;
i /= 2;
}
// Heap and HeapIndices are kinda inverses
this->Heap[ i ] = v;
this->HeapIndices[ v ] = i;
}
int HeapExtractMin()
{
if ( this->HeapSize == 0 )
{
return -1;
}
int minv = this->Heap[ 1 ];
this->HeapIndices[ minv ] = -1;
this->Heap[ 1 ] = this->Heap[ this->HeapSize ];
this->HeapIndices[ this->Heap[1] ]= 1;
this->HeapSize--;
this->Heapify( 1 );
return minv;
}
void HeapDecreaseKey(const int& v)
{
// where in Heap is vertex v
int i = this->HeapIndices[ v ];
if ( i < 1 || i > static_cast<int>(this->HeapSize) )
{
return;
}
while ( i > 1 &&
this->CumulativeWeights[ this->Heap[ i/2 ] ] >
this->CumulativeWeights[ v ] )
{
this->Heap[ i ] = this->Heap[i/2];
this->HeapIndices[ this->Heap[i] ] = i;
i /= 2;
}
// Heap and HeapIndices are kinda inverses
this->Heap[ i ] = v;
this->HeapIndices[ v ] = i;
}
void ResetHeap()
{
this->HeapSize = 0;
}
void InitializeHeap(const int& size)
{
this->Heap.resize( size + 1 );
this->HeapIndices.resize( size );
}
private:
unsigned int HeapSize;
// The priority que (a binary heap) with vertex indices.
std::vector<int> Heap;
// HeapIndices(v) the position of v in Heap (HeapIndices and Heap are kind of inverses).
std::vector<int> HeapIndices;
};
#endif
// VTK-HeaderTest-Exclude: vtkDijkstraGraphInternals.h
|
