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Backporting refactoring from master branch

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This commit is contained in:
DennisOSRM 2012-11-15 15:10:49 +01:00
parent 11d4d3ec30
commit 868d6ec776
1 changed files with 54 additions and 54 deletions
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106
Algorithms/DouglasPeucker.h
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@ -29,7 +29,7 @@ or see http://www.gnu.org/licenses/agpl.txt.
#include "../DataStructures/Coordinate.h"
/*This class object computes the bitvector of indicating generalized input points
* according to the (Ramer-)Douglas-Peucker algorithm. Runtime n\log n calls to fastDistance
* according to the (Ramer-)Douglas-Peucker algorithm.
*
* Input is vector of pairs. Each pair consists of the point information and a bit
* indicating if the points is present in the generalization.
@ -37,7 +37,7 @@ or see http://www.gnu.org/licenses/agpl.txt.
//These thresholds are more or less heuristically chosen.
// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
static double DouglasPeuckerThresholds[19] = { 32000000, 16240000, 80240000, 40240000, 20000000, 10000000, 500000, 240000, 120000, 60000, 30000, 19000, 5000, 2000, 200, 16, 6, 3, 3 };
static double DouglasPeuckerThresholds[19] = { 32000000., 16240000., 80240000., 40240000., 20000000., 10000000., 500000., 240000., 120000., 60000., 30000., 19000., 5000., 2000., 200, 16, 6, 3. , 3. };
template<class PointT>
class DouglasPeucker {
@ -45,57 +45,6 @@ private:
typedef std::pair<std::size_t, std::size_t> PairOfPoints;
//Stack to simulate the recursion
std::stack<PairOfPoints > recursionStack;
public:
void Run(std::vector<PointT> & inputVector, const unsigned zoomLevel) {
const unsigned sizeOfInputVector = inputVector.size();
{
assert(zoomLevel < 19);
assert(1 < inputVector.size());
std::size_t leftBorderOfRange = 0;
std::size_t rightBorderOfRange = 1;
//Sweep linerarily over array and identify those ranges that need to be checked
//decision points have been previously marked
do {
assert(inputVector[leftBorderOfRange].necessary);
assert(inputVector.back().necessary);
if(inputVector[rightBorderOfRange].necessary) {
recursionStack.push(std::make_pair(leftBorderOfRange, rightBorderOfRange));
leftBorderOfRange = rightBorderOfRange;
}
++rightBorderOfRange;
} while( rightBorderOfRange < sizeOfInputVector);
}
while(!recursionStack.empty()) {
//pop next element
const PairOfPoints pair = recursionStack.top();
recursionStack.pop();
assert(inputVector[pair.first].necessary);
assert(inputVector[pair.second].necessary);
assert(pair.second < sizeOfInputVector);
assert(pair.first < pair.second);
int maxDistance = INT_MIN;
std::size_t indexOfFarthestElement = pair.second;
//find index idx of element with maxDistance
for(std::size_t i = pair.first+1; i < pair.second; ++i){
const int distance = fastDistance(inputVector[i].location, inputVector[pair.first].location, inputVector[pair.second].location);
if(distance > DouglasPeuckerThresholds[zoomLevel] && distance > maxDistance) {
indexOfFarthestElement = i;
maxDistance = distance;
}
}
if (maxDistance > DouglasPeuckerThresholds[zoomLevel]) {
// mark idx as necessary
inputVector[indexOfFarthestElement].necessary = true;
if (1 < indexOfFarthestElement - pair.first) {
recursionStack.push(std::make_pair(pair.first, indexOfFarthestElement) );
}
if (1 < pair.second - indexOfFarthestElement)
recursionStack.push(std::make_pair(indexOfFarthestElement, pair.second) );
}
}
}
/**
* This distance computation does integer arithmetic only and is about twice as fast as
@ -124,6 +73,57 @@ public:
return dist;
}
public:
void Run(std::vector<PointT> & inputVector, const unsigned zoomLevel) {
{
assert(zoomLevel < 19);
assert(1 < inputVector.size());
std::size_t leftBorderOfRange = 0;
std::size_t rightBorderOfRange = 1;
//Sweep linerarily over array and identify those ranges that need to be checked
// recursionStack.hint(inputVector.size());
do {
assert(inputVector[leftBorderOfRange].necessary);
assert(inputVector.back().necessary);
if(inputVector[rightBorderOfRange].necessary) {
recursionStack.push(std::make_pair(leftBorderOfRange, rightBorderOfRange));
leftBorderOfRange = rightBorderOfRange;
}
++rightBorderOfRange;
} while( rightBorderOfRange < inputVector.size());
}
while(!recursionStack.empty()) {
//pop next element
const PairOfPoints pair = recursionStack.top();
recursionStack.pop();
assert(inputVector[pair.first].necessary);
assert(inputVector[pair.second].necessary);
assert(pair.second < inputVector.size());
assert(pair.first < pair.second);
int maxDistance = INT_MIN;
std::size_t indexOfFarthestElement = pair.second;
//find index idx of element with maxDistance
for(std::size_t i = pair.first+1; i < pair.second; ++i){
const double distance = std::fabs(fastDistance(inputVector[i].location, inputVector[pair.first].location, inputVector[pair.second].location));
if(distance > DouglasPeuckerThresholds[zoomLevel] && distance > maxDistance) {
indexOfFarthestElement = i;
maxDistance = distance;
}
}
if (maxDistance > DouglasPeuckerThresholds[zoomLevel]) {
// mark idx as necessary
inputVector[indexOfFarthestElement].necessary = true;
if (1 < indexOfFarthestElement - pair.first) {
recursionStack.push(std::make_pair(pair.first, indexOfFarthestElement) );
}
if (1 < pair.second - indexOfFarthestElement)
recursionStack.push(std::make_pair(indexOfFarthestElement, pair.second) );
}
}
}
};
#endif /* DOUGLASPEUCKER_H_ */