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