bd_pr_search.cpp

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//----------------------------------------------------------------------
// File:                        bd_pr_search.cpp
// Programmer:          David Mount
// Description:         Priority search for bd-trees
// Last modified:       01/04/05 (Version 1.0)
//----------------------------------------------------------------------
// 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
//----------------------------------------------------------------------

#include "bd_tree.h"                                    // bd-tree declarations
#include "kd_pr_search.h"                               // kd priority search declarations

//----------------------------------------------------------------------
//      Approximate priority searching for bd-trees.
//              See the file kd_pr_search.cc for general information on the
//              approximate nearest neighbor priority search algorithm.  Here
//              we include the extensions for shrinking nodes.
//----------------------------------------------------------------------

//----------------------------------------------------------------------
//      bd_shrink::ann_search - search a shrinking node
//----------------------------------------------------------------------

void ANNbd_shrink::ann_pri_search(ANNdist box_dist)
{
        ANNdist inner_dist = 0;                                         // distance to inner box
        for (int i = 0; i < n_bnds; i++) {                      // is query point in the box?
                if (bnds[i].out(ANNprQ)) {                              // outside this bounding side?
                                                                                                // add to inner distance
                        inner_dist = (ANNdist) ANN_SUM(inner_dist, bnds[i].dist(ANNprQ));
                }
        }
        if (inner_dist <= box_dist) {                           // if inner box is closer
                if (child[ANN_OUT] != KD_TRIVIAL)               // enqueue outer if not trivial
                        ANNprBoxPQ->insert(box_dist,child[ANN_OUT]);
                                                                                                // continue with inner child
                child[ANN_IN]->ann_pri_search(inner_dist);
        }
        else {                                                                          // if outer box is closer
                if (child[ANN_IN] != KD_TRIVIAL)                // enqueue inner if not trivial
                        ANNprBoxPQ->insert(inner_dist,child[ANN_IN]);
                                                                                                // continue with outer child
                child[ANN_OUT]->ann_pri_search(box_dist);
        }
        ANN_FLOP(3*n_bnds)                                                      // increment floating ops
        ANN_SHR(1)                                                                      // one more shrinking node
}