cosmotool/sample/testkd.cpp

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2009-01-11 17:07:57 +01:00
#include <ctime>
#include <cassert>
#include <cstdlib>
#include <iostream>
#include "mykdtree.hpp"
#define NTRY 5000000
#define ND 2
using namespace std;
using namespace CosmoTool;
typedef KDTree<ND,char> MyTree;
typedef KDCell<ND,char> MyCell;
MyCell *findNearest(MyTree::coords& xc, MyCell *cells, uint32_t Ncells)
{
MyCell *near2 = 0;
double R2 = INFINITY;
for (int i = 0; i < Ncells; i++)
{
double d2 = 0;
for (int j = 0; j < ND; j++)
{
double delta = xc[j]-cells[i].coord[j];
d2 += delta*delta;
}
if (d2 < R2)
{
near2 = &cells[i];
R2 = d2;
}
}
return near2;
}
int main()
{
uint32_t Ncells = 100000;
MyCell *cells = new MyCell[Ncells];
for (int i = 0; i < Ncells; i++)
{
cells[i].active = true;
for (int l = 0; l < ND; l++)
cells[i].coord[l] = drand48();
}
MyTree tree(cells, Ncells);
MyTree::coords *xc = new MyTree::coords[NTRY];
cout << "Generating seeds..." << endl;
for (int k = 0; k < NTRY; k++)
{
for (int l = 0; l < ND; l++)
xc[k][l] = drand48();
}
// Check consistency
cout << "Check consistency..." << endl;
#if 0
for (int k = 0; k < NTRY; k++) {
MyCell *near = tree.getNearestNeighbour(xc[k]);
MyCell *near2 = findNearest(xc[k], cells, Ncells);
assert(near == near2);
}
#endif
cout << "Check timing..." << endl;
// Check timing
clock_t startTimer = clock();
for (int k = 0; k < NTRY; k++) {
MyCell *near = tree.getNearestNeighbour(xc[k]);
}
clock_t endTimer = clock();
clock_t delta = endTimer-startTimer;
double myTime = delta*1.0/CLOCKS_PER_SEC * 1000000.0;
cout << "KDTree search/sec = " << myTime/NTRY << " us" << endl;
startTimer = clock();
for (int k = 0; k < NTRY; k++) {
MyCell *near = findNearest(xc[k], cells, Ncells);
}
endTimer = clock();
delta = endTimer-startTimer;
myTime = delta*1.0/CLOCKS_PER_SEC * 1000000.0;
cout << "Direct search/sec = " << myTime/NTRY << " us" << endl;
return 0;
}