mgs/median-comparison
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Separate approx. MoM and exact with quickselect

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This commit is contained in:
Karl 2020-10-18 16:41:52 +02:00
parent 6357dd605b
commit 16f10c0937
1 changed files with 14 additions and 8 deletions
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22
main.cpp
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@ -13,7 +13,7 @@
int main(int argc, char** argv)
{
// read test values from input file
std::string type = "init\t\t\t\t\t";
std::string type = "init\t\t\t\t\t\t";
Timing::getInstance()->startRecord(type);
std::vector<uint32_t > numbers = readFromFile("testdata");
Timing::getInstance()->stopRecord(type);
@ -32,14 +32,14 @@ int main(int argc, char** argv)
uint32_t* array = new uint32_t[numbers.size()];
// vollständige Sortierung mit Quicksort und Ausgabe des mittleren Elements
type = "quicksort median\t\t\t";
type = "quicksort median\t\t\t\t";
Timing::getInstance()->startRecord(type);
std::cout << type << getQuicksortMedian(numbers, idxMed) << std::endl;
Timing::getInstance()->stopRecord(type);
// comparison of std::qsort and std::sort
// using std quicksort for array
type = "array quicksort\t\t\t\t";
type = "array quicksort\t\t\t\t\t";
std::copy(numbers.begin(), numbers.end(), array);
Timing::getInstance()->startRecord(type);
std::qsort(array, numbers.size(), sizeof(uint32_t), compare);
@ -47,7 +47,7 @@ int main(int argc, char** argv)
Timing::getInstance()->stopRecord(type);
// comparison "quick" sort with std::sort (introsort)
type = "array std sort\t\t\t\t";
type = "array std sort\t\t\t\t\t";
std::copy(numbers.begin(), numbers.end(), array);
Timing::getInstance()->startRecord(type);
std::sort(array, array + numbers.size());
@ -55,25 +55,31 @@ int main(int argc, char** argv)
Timing::getInstance()->stopRecord(type);
// vorgestellter Randomzized - Select rekursiv implementiert
type = "randomized select\t\t\t";
type = "randomized select\t\t\t\t";
Timing::getInstance()->startRecord(type);
std::cout << type << getRandomizedSelectMedian(numbers, 0, numbers.size() - 1, idxMed + 1) << std::endl;
Timing::getInstance()->stopRecord(type);
// ein weiterer Median - Algorithmus aus der Literatur - implemented with std::vector
type = "vector median of medians\t\t";
type = "vector median of medians only (approximative)\t";
Timing::getInstance()->startRecord(type);
std::cout << type << numbers[pivot(numbers, 0, numbers.size() - 1)] << std::endl;
Timing::getInstance()->stopRecord(type);
// ein weiterer Median - Algorithmus aus der Literatur - implemented with std::vector
type = "vector median of medians + quickselect (exact)\t";
Timing::getInstance()->startRecord(type);
std::cout << type << getMedianOfMedians(numbers, 0, numbers.size() - 1, idxMed) << std::endl;
Timing::getInstance()->stopRecord(type);
// noch ein ein weiterer Median - Algorithmus weil wir so cool sind
type = "wirth kth element\t\t\t";
type = "wirth kth element\t\t\t\t";
Timing::getInstance()->startRecord(type);
std::cout << type << getWirthKthSmallest(numbers, idxMed) << std::endl;
Timing::getInstance()->stopRecord(type);
// Verwendung des C++ STL function templates nth_element
type = "nth element\t\t\t\t";
type = "nth element\t\t\t\t\t";
Timing::getInstance()->startRecord(type);
std::nth_element(numbers.begin(), numbers.begin() + idxMed, numbers.end());
std::cout << type << numbers[idxMed] << std::endl;