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2012-09-16 12:33:11 +00:00
//----------------------------------------------------------------------
// File: ann_sample.cpp
// Programmer: Sunil Arya and David Mount
// Last modified: 03/04/98 (Release 0.1)
// Description: Sample program for ANN
//----------------------------------------------------------------------
// Copyright (c) 1997-2005 University of Maryland and Sunil Arya and
// David Mount. All Rights Reserved.
//
// This software and related documentation is part of the Approximate
// Nearest Neighbor Library (ANN). This software is provided under
// the provisions of the Lesser GNU Public License (LGPL). See the
// file ../ReadMe.txt for further information.
//
// The University of Maryland (U.M.) and the authors make no
// representations about the suitability or fitness of this software for
// any purpose. It is provided "as is" without express or implied
// warranty.
//----------------------------------------------------------------------
#include <cstdlib> // C standard library
#include <cstdio> // C I/O (for sscanf)
#include <cstring> // string manipulation
#include <fstream> // file I/O
#include <ANN/ANN.h> // ANN declarations
using namespace std; // make std:: accessible
//----------------------------------------------------------------------
// ann_sample
//
// This is a simple sample program for the ANN library. After compiling,
// it can be run as follows.
//
// ann_sample [-d dim] [-max mpts] [-nn k] [-e eps] [-df data] [-qf query]
//
// where
// dim is the dimension of the space (default = 2)
// mpts maximum number of data points (default = 1000)
// k number of nearest neighbors per query (default 1)
// eps is the error bound (default = 0.0)
// data file containing data points
// query file containing query points
//
// Results are sent to the standard output.
//----------------------------------------------------------------------
//----------------------------------------------------------------------
// Parameters that are set in getArgs()
//----------------------------------------------------------------------
void getArgs(int argc, char **argv); // get command-line arguments
int k = 1; // number of nearest neighbors
int dim = 2; // dimension
double eps = 0; // error bound
int maxPts = 1000; // maximum number of data points
istream* dataIn = NULL; // input for data points
istream* queryIn = NULL; // input for query points
bool readPt(istream &in, ANNpoint p) // read point (false on EOF)
{
for (int i = 0; i < dim; i++) {
if(!(in >> p[i])) return false;
}
return true;
}
void printPt(ostream &out, ANNpoint p) // print point
{
out << "(" << p[0];
for (int i = 1; i < dim; i++) {
out << ", " << p[i];
}
out << ")\n";
}
int main(int argc, char **argv)
{
int nPts; // actual number of data points
ANNpointArray dataPts; // data points
ANNpoint queryPt; // query point
ANNidxArray nnIdx; // near neighbor indices
ANNdistArray dists; // near neighbor distances
ANNkd_tree* kdTree; // search structure
getArgs(argc, argv); // read command-line arguments
queryPt = annAllocPt(dim); // allocate query point
dataPts = annAllocPts(maxPts, dim); // allocate data points
nnIdx = new ANNidx[k]; // allocate near neigh indices
dists = new ANNdist[k]; // allocate near neighbor dists
nPts = 0; // read data points
cout << "Data Points:\n";
while (nPts < maxPts && readPt(*dataIn, dataPts[nPts])) {
printPt(cout, dataPts[nPts]);
nPts++;
}
kdTree = new ANNkd_tree( // build search structure
dataPts, // the data points
nPts, // number of points
dim); // dimension of space
while (readPt(*queryIn, queryPt)) { // read query points
cout << "Query point: "; // echo query point
printPt(cout, queryPt);
kdTree->annkSearch( // search
queryPt, // query point
k, // number of near neighbors
nnIdx, // nearest neighbors (returned)
dists, // distance (returned)
eps); // error bound
cout << "\tNN:\tIndex\tDistance\n";
for (int i = 0; i < k; i++) { // print summary
dists[i] = sqrt(dists[i]); // unsquare distance
cout << "\t" << i << "\t" << nnIdx[i] << "\t" << dists[i] << "\n";
}
}
delete [] nnIdx; // clean things up
delete [] dists;
delete kdTree;
annClose(); // done with ANN
return EXIT_SUCCESS;
}
//----------------------------------------------------------------------
// getArgs - get command line arguments
//----------------------------------------------------------------------
void getArgs(int argc, char **argv)
{
static ifstream dataStream; // data file stream
static ifstream queryStream; // query file stream
if (argc <= 1) { // no arguments
cerr << "Usage:\n\n"
<< " ann_sample [-d dim] [-max m] [-nn k] [-e eps] [-df data]"
" [-qf query]\n\n"
<< " where:\n"
<< " dim dimension of the space (default = 2)\n"
<< " m maximum number of data points (default = 1000)\n"
<< " k number of nearest neighbors per query (default 1)\n"
<< " eps the error bound (default = 0.0)\n"
<< " data name of file containing data points\n"
<< " query name of file containing query points\n\n"
<< " Results are sent to the standard output.\n"
<< "\n"
<< " To run this demo use:\n"
<< " ann_sample -df data.pts -qf query.pts\n";
exit(0);
}
int i = 1;
while (i < argc) { // read arguments
if (!strcmp(argv[i], "-d")) { // -d option
dim = atoi(argv[++i]); // get dimension to dump
}
else if (!strcmp(argv[i], "-max")) { // -max option
maxPts = atoi(argv[++i]); // get max number of points
}
else if (!strcmp(argv[i], "-nn")) { // -nn option
k = atoi(argv[++i]); // get number of near neighbors
}
else if (!strcmp(argv[i], "-e")) { // -e option
sscanf(argv[++i], "%lf", &eps); // get error bound
}
else if (!strcmp(argv[i], "-df")) { // -df option
dataStream.open(argv[++i], ios::in);// open data file
if (!dataStream) {
cerr << "Cannot open data file\n";
exit(1);
}
dataIn = &dataStream; // make this the data stream
}
else if (!strcmp(argv[i], "-qf")) { // -qf option
queryStream.open(argv[++i], ios::in);// open query file
if (!queryStream) {
cerr << "Cannot open query file\n";
exit(1);
}
queryIn = &queryStream; // make this query stream
}
else { // illegal syntax
cerr << "Unrecognized option.\n";
exit(1);
}
i++;
}
if (dataIn == NULL || queryIn == NULL) {
cerr << "-df and -qf options must be specified\n";
exit(1);
}
}