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Diffstat (limited to 'geom_bottleneck/bottleneck/src/brute.cpp')
| -rw-r--r-- | geom_bottleneck/bottleneck/src/brute.cpp | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/geom_bottleneck/bottleneck/src/brute.cpp b/geom_bottleneck/bottleneck/src/brute.cpp new file mode 100644 index 0000000..200bc35 --- /dev/null +++ b/geom_bottleneck/bottleneck/src/brute.cpp @@ -0,0 +1,110 @@ +//---------------------------------------------------------------------- +// File: brute.cpp +// Programmer: Sunil Arya and David Mount +// Description: Brute-force nearest neighbors +// Last modified: 05/03/05 (Version 1.1) +//---------------------------------------------------------------------- +// 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. +//---------------------------------------------------------------------- +// History: +// Revision 0.1 03/04/98 +// Initial release +// Revision 1.1 05/03/05 +// Added fixed-radius kNN search +//---------------------------------------------------------------------- + +#include <ANN/ANNx.h> // all ANN includes +#include "pr_queue_k.h" // k element priority queue + +//---------------------------------------------------------------------- +// Brute-force search simply stores a pointer to the list of +// data points and searches linearly for the nearest neighbor. +// The k nearest neighbors are stored in a k-element priority +// queue (which is implemented in a pretty dumb way as well). +// +// If ANN_ALLOW_SELF_MATCH is ANNfalse then data points at distance +// zero are not considered. +// +// Note that the error bound eps is passed in, but it is ignored. +// These routines compute exact nearest neighbors (which is needed +// for validation purposes in ann_test.cpp). +//---------------------------------------------------------------------- + +ANNbruteForce::ANNbruteForce( // constructor from point array + ANNpointArray pa, // point array + int n, // number of points + int dd) // dimension +{ + dim = dd; n_pts = n; pts = pa; +} + +ANNbruteForce::~ANNbruteForce() { } // destructor (empty) + +void ANNbruteForce::annkSearch( // approx k near neighbor search + ANNpoint q, // query point + int k, // number of near neighbors to return + ANNidxArray nn_idx, // nearest neighbor indices (returned) + ANNdistArray dd, // dist to near neighbors (returned) + double eps) // error bound (ignored) +{ + ANNmin_k mk(k); // construct a k-limited priority queue + int i; + + if (k > n_pts) { // too many near neighbors? + annError("Requesting more near neighbors than data points", ANNabort); + } + // run every point through queue + for (i = 0; i < n_pts; i++) { + // compute distance to point + ANNdist sqDist = annDist(dim, pts[i], q); + if (ANN_ALLOW_SELF_MATCH || sqDist != 0) + mk.insert(sqDist, i); + } + for (i = 0; i < k; i++) { // extract the k closest points + dd[i] = mk.ith_smallest_key(i); + nn_idx[i] = mk.ith_smallest_info(i); + } +} + +int ANNbruteForce::annkFRSearch( // approx fixed-radius kNN search + ANNpoint q, // query point + ANNdist sqRad, // squared radius + int k, // number of near neighbors to return + ANNidxArray nn_idx, // nearest neighbor array (returned) + ANNdistArray dd, // dist to near neighbors (returned) + double eps) // error bound +{ + ANNmin_k mk(k); // construct a k-limited priority queue + int i; + int pts_in_range = 0; // number of points in query range + // run every point through queue + for (i = 0; i < n_pts; i++) { + // compute distance to point + ANNdist sqDist = annDist(dim, pts[i], q); + if (sqDist <= sqRad && // within radius bound + (ANN_ALLOW_SELF_MATCH || sqDist != 0)) { // ...and no self match + mk.insert(sqDist, i); + pts_in_range++; + } + } + for (i = 0; i < k; i++) { // extract the k closest points + if (dd != NULL) + dd[i] = mk.ith_smallest_key(i); + if (nn_idx != NULL) + nn_idx[i] = mk.ith_smallest_info(i); + } + + return pts_in_range; +} +-\n}\n |