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447 lines
16 KiB
C++
447 lines
16 KiB
C++
//----------------------------------------------------------------------
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// File: kd_dump.cc
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// Programmer: David Mount
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// Description: Dump and Load for kd- and bd-trees
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// Last modified: 01/04/05 (Version 1.0)
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//----------------------------------------------------------------------
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// Copyright (c) 1997-2005 University of Maryland and Sunil Arya and
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// David Mount. All Rights Reserved.
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//
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// This software and related documentation is part of the Approximate
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// Nearest Neighbor Library (ANN). This software is provided under
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// the provisions of the Lesser GNU Public License (LGPL). See the
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// file ../ReadMe.txt for further information.
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//
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// The University of Maryland (U.M.) and the authors make no
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// representations about the suitability or fitness of this software for
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// any purpose. It is provided "as is" without express or implied
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// warranty.
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//----------------------------------------------------------------------
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// History:
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// Revision 0.1 03/04/98
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// Initial release
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// Revision 1.0 04/01/05
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// Moved dump out of kd_tree.cc into this file.
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// Added kd-tree load constructor.
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//----------------------------------------------------------------------
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// This file contains routines for dumping kd-trees and bd-trees and
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// reloading them. (It is an abuse of policy to include both kd- and
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// bd-tree routines in the same file, sorry. There should be no problem
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// in deleting the bd- versions of the routines if they are not
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// desired.)
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//----------------------------------------------------------------------
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#include <string.h>
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#include <stdlib.h>
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#include "kd_tree.h" // kd-tree declarations
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#include "bd_tree.h" // bd-tree declarations
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using namespace std; // make std:: available
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//----------------------------------------------------------------------
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// Constants
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//----------------------------------------------------------------------
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const int STRING_LEN = 500; // maximum string length
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const double EPSILON = 1E-5; // small number for float comparison
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enum ANNtreeType {KD_TREE, BD_TREE}; // tree types (used in loading)
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//----------------------------------------------------------------------
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// Procedure declarations
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//----------------------------------------------------------------------
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static ANNkd_ptr annReadDump( // read dump file
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istream &in, // input stream
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ANNtreeType tree_type, // type of tree expected
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ANNpointArray &the_pts, // new points (if applic)
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ANNidxArray &the_pidx, // point indices (returned)
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int &the_dim, // dimension (returned)
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int &the_n_pts, // number of points (returned)
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int &the_bkt_size, // bucket size (returned)
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ANNpoint &the_bnd_box_lo, // low bounding point
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ANNpoint &the_bnd_box_hi); // high bounding point
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static ANNkd_ptr annReadTree( // read tree-part of dump file
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istream &in, // input stream
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ANNtreeType tree_type, // type of tree expected
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ANNidxArray the_pidx, // point indices (modified)
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int &next_idx); // next index (modified)
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//----------------------------------------------------------------------
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// ANN kd- and bd-tree Dump Format
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// The dump file begins with a header containing the version of
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// ANN, an optional section containing the points, followed by
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// a description of the tree. The tree is printed in preorder.
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//
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// Format:
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// #ANN <version number> <comments> [END_OF_LINE]
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// points <dim> <n_pts> (point coordinates: this is optional)
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// 0 <xxx> <xxx> ... <xxx> (point indices and coordinates)
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// 1 <xxx> <xxx> ... <xxx>
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// ...
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// tree <dim> <n_pts> <bkt_size>
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// <xxx> <xxx> ... <xxx> (lower end of bounding box)
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// <xxx> <xxx> ... <xxx> (upper end of bounding box)
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// If the tree is null, then a single line "null" is
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// output. Otherwise the nodes of the tree are printed
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// one per line in preorder. Leaves and splitting nodes
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// have the following formats:
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// Leaf node:
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// leaf <n_pts> <bkt[0]> <bkt[1]> ... <bkt[n-1]>
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// Splitting nodes:
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// split <cut_dim> <cut_val> <lo_bound> <hi_bound>
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//
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// For bd-trees:
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//
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// Shrinking nodes:
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// shrink <n_bnds>
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// <cut_dim> <cut_val> <side>
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// <cut_dim> <cut_val> <side>
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// ... (repeated n_bnds times)
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//----------------------------------------------------------------------
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void ANNkd_tree::Dump( // dump entire tree
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ANNbool with_pts, // print points as well?
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ostream &out) // output stream
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{
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out << "#ANN " << ANNversion << "\n";
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out.precision(ANNcoordPrec); // use full precision in dumping
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if (with_pts) { // print point coordinates
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out << "points " << dim << " " << n_pts << "\n";
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for (int i = 0; i < n_pts; i++) {
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out << i << " ";
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annPrintPt(pts[i], dim, out);
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out << "\n";
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}
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}
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out << "tree " // print tree elements
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<< dim << " "
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<< n_pts << " "
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<< bkt_size << "\n";
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annPrintPt(bnd_box_lo, dim, out); // print lower bound
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out << "\n";
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annPrintPt(bnd_box_hi, dim, out); // print upper bound
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out << "\n";
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if (root == NULL) // empty tree?
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out << "null\n";
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else {
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root->dump(out); // invoke printing at root
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}
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out.precision(0); // restore default precision
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}
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void ANNkd_split::dump( // dump a splitting node
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ostream &out) // output stream
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{
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out << "split " << cut_dim << " " << cut_val << " ";
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out << cd_bnds[ANN_LO] << " " << cd_bnds[ANN_HI] << "\n";
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child[ANN_LO]->dump(out); // print low child
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child[ANN_HI]->dump(out); // print high child
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}
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void ANNkd_leaf::dump( // dump a leaf node
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ostream &out) // output stream
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{
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if (this == KD_TRIVIAL) { // canonical trivial leaf node
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out << "leaf 0\n"; // leaf no points
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}
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else{
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out << "leaf " << n_pts;
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for (int j = 0; j < n_pts; j++) {
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out << " " << bkt[j];
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}
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out << "\n";
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}
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}
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void ANNbd_shrink::dump( // dump a shrinking node
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ostream &out) // output stream
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{
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out << "shrink " << n_bnds << "\n";
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for (int j = 0; j < n_bnds; j++) {
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out << bnds[j].cd << " " << bnds[j].cv << " " << bnds[j].sd << "\n";
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}
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child[ANN_IN]->dump(out); // print in-child
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child[ANN_OUT]->dump(out); // print out-child
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}
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//----------------------------------------------------------------------
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// Load kd-tree from dump file
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// This rebuilds a kd-tree which was dumped to a file. The dump
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// file contains all the basic tree information according to a
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// preorder traversal. We assume that the dump file also contains
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// point data. (This is to guarantee the consistency of the tree.)
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// If not, then an error is generated.
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//
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// Indirectly, this procedure allocates space for points, point
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// indices, all nodes in the tree, and the bounding box for the
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// tree. When the tree is destroyed, all but the points are
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// deallocated.
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//
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// This routine calls annReadDump to do all the work.
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//----------------------------------------------------------------------
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ANNkd_tree::ANNkd_tree( // build from dump file
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istream &in) // input stream for dump file
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{
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int the_dim; // local dimension
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int the_n_pts; // local number of points
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int the_bkt_size; // local number of points
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ANNpoint the_bnd_box_lo; // low bounding point
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ANNpoint the_bnd_box_hi; // high bounding point
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ANNpointArray the_pts; // point storage
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ANNidxArray the_pidx; // point index storage
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ANNkd_ptr the_root; // root of the tree
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the_root = annReadDump( // read the dump file
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in, // input stream
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KD_TREE, // expecting a kd-tree
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the_pts, // point array (returned)
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the_pidx, // point indices (returned)
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the_dim, the_n_pts, the_bkt_size, // basic tree info (returned)
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the_bnd_box_lo, the_bnd_box_hi); // bounding box info (returned)
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// create a skeletal tree
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SkeletonTree(the_n_pts, the_dim, the_bkt_size, the_pts, the_pidx);
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bnd_box_lo = the_bnd_box_lo;
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bnd_box_hi = the_bnd_box_hi;
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root = the_root; // set the root
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}
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ANNbd_tree::ANNbd_tree( // build bd-tree from dump file
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istream &in) : ANNkd_tree() // input stream for dump file
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{
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int the_dim; // local dimension
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int the_n_pts; // local number of points
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int the_bkt_size; // local number of points
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ANNpoint the_bnd_box_lo; // low bounding point
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ANNpoint the_bnd_box_hi; // high bounding point
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ANNpointArray the_pts; // point storage
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ANNidxArray the_pidx; // point index storage
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ANNkd_ptr the_root; // root of the tree
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the_root = annReadDump( // read the dump file
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in, // input stream
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BD_TREE, // expecting a bd-tree
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the_pts, // point array (returned)
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the_pidx, // point indices (returned)
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the_dim, the_n_pts, the_bkt_size, // basic tree info (returned)
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the_bnd_box_lo, the_bnd_box_hi); // bounding box info (returned)
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// create a skeletal tree
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SkeletonTree(the_n_pts, the_dim, the_bkt_size, the_pts, the_pidx);
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bnd_box_lo = the_bnd_box_lo;
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bnd_box_hi = the_bnd_box_hi;
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root = the_root; // set the root
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}
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//----------------------------------------------------------------------
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// annReadDump - read a dump file
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//
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// This procedure reads a dump file, constructs a kd-tree
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// and returns all the essential information needed to actually
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// construct the tree. Because this procedure is used for
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// constructing both kd-trees and bd-trees, the second argument
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// is used to indicate which type of tree we are expecting.
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//----------------------------------------------------------------------
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static ANNkd_ptr annReadDump(
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istream &in, // input stream
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ANNtreeType tree_type, // type of tree expected
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ANNpointArray &the_pts, // new points (returned)
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ANNidxArray &the_pidx, // point indices (returned)
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int &the_dim, // dimension (returned)
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int &the_n_pts, // number of points (returned)
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int &the_bkt_size, // bucket size (returned)
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ANNpoint &the_bnd_box_lo, // low bounding point (ret'd)
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ANNpoint &the_bnd_box_hi) // high bounding point (ret'd)
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{
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int j;
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char str[STRING_LEN]; // storage for string
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char version[STRING_LEN]; // ANN version number
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ANNkd_ptr the_root = NULL;
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//------------------------------------------------------------------
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// Input file header
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//------------------------------------------------------------------
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in >> str; // input header
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if (strcmp(str, "#ANN") != 0) { // incorrect header
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annError("Incorrect header for dump file", ANNabort);
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}
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in.getline(version, STRING_LEN); // get version (ignore)
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//------------------------------------------------------------------
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// Input the points
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// An array the_pts is allocated and points are read from
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// the dump file.
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//------------------------------------------------------------------
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in >> str; // get major heading
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if (strcmp(str, "points") == 0) { // points section
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in >> the_dim; // input dimension
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in >> the_n_pts; // number of points
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// allocate point storage
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the_pts = annAllocPts(the_n_pts, the_dim);
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for (int i = 0; i < the_n_pts; i++) { // input point coordinates
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ANNidx idx; // point index
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in >> idx; // input point index
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if (idx < 0 || idx >= the_n_pts) {
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annError("Point index is out of range", ANNabort);
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}
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for (j = 0; j < the_dim; j++) {
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in >> the_pts[idx][j]; // read point coordinates
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}
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}
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in >> str; // get next major heading
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}
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else { // no points were input
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annError("Points must be supplied in the dump file", ANNabort);
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}
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//------------------------------------------------------------------
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// Input the tree
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// After the basic header information, we invoke annReadTree
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// to do all the heavy work. We create our own array of
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// point indices (so we can pass them to annReadTree())
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// but we do not deallocate them. They will be deallocated
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// when the tree is destroyed.
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//------------------------------------------------------------------
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if (strcmp(str, "tree") == 0) { // tree section
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in >> the_dim; // read dimension
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in >> the_n_pts; // number of points
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in >> the_bkt_size; // bucket size
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the_bnd_box_lo = annAllocPt(the_dim); // allocate bounding box pts
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the_bnd_box_hi = annAllocPt(the_dim);
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for (j = 0; j < the_dim; j++) { // read bounding box low
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in >> the_bnd_box_lo[j];
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}
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for (j = 0; j < the_dim; j++) { // read bounding box low
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in >> the_bnd_box_hi[j];
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}
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the_pidx = new ANNidx[the_n_pts]; // allocate point index array
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int next_idx = 0; // number of indices filled
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// read the tree and indices
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the_root = annReadTree(in, tree_type, the_pidx, next_idx);
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if (next_idx != the_n_pts) { // didn't see all the points?
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annError("Didn't see as many points as expected", ANNwarn);
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}
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}
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else {
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annError("Illegal dump format. Expecting section heading", ANNabort);
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}
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return the_root;
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}
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//----------------------------------------------------------------------
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// annReadTree - input tree and return pointer
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//
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// annReadTree reads in a node of the tree, makes any recursive
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// calls as needed to input the children of this node (if internal).
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// It returns a pointer to the node that was created. An array
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// of point indices is given along with a pointer to the next
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// available location in the array. As leaves are read, their
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// point indices are stored here, and the point buckets point
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// to the first entry in the array.
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//
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// Recall that these are the formats. The tree is given in
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// preorder.
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//
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// Leaf node:
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// leaf <n_pts> <bkt[0]> <bkt[1]> ... <bkt[n-1]>
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// Splitting nodes:
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// split <cut_dim> <cut_val> <lo_bound> <hi_bound>
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//
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// For bd-trees:
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//
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// Shrinking nodes:
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// shrink <n_bnds>
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// <cut_dim> <cut_val> <side>
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// <cut_dim> <cut_val> <side>
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// ... (repeated n_bnds times)
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//----------------------------------------------------------------------
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static ANNkd_ptr annReadTree(
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istream &in, // input stream
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ANNtreeType tree_type, // type of tree expected
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ANNidxArray the_pidx, // point indices (modified)
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int &next_idx) // next index (modified)
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{
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char tag[STRING_LEN]; // tag (leaf, split, shrink)
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int n_pts; // number of points in leaf
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int cd; // cut dimension
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ANNcoord cv; // cut value
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ANNcoord lb; // low bound
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ANNcoord hb; // high bound
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int n_bnds; // number of bounding sides
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int sd; // which side
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in >> tag; // input node tag
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if (strcmp(tag, "null") == 0) { // null tree
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return NULL;
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}
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//------------------------------------------------------------------
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// Read a leaf
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//------------------------------------------------------------------
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if (strcmp(tag, "leaf") == 0) { // leaf node
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in >> n_pts; // input number of points
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int old_idx = next_idx; // save next_idx
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if (n_pts == 0) { // trivial leaf
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return KD_TRIVIAL;
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}
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else {
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for (int i = 0; i < n_pts; i++) { // input point indices
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in >> the_pidx[next_idx++]; // store in array of indices
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}
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}
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return new ANNkd_leaf(n_pts, &the_pidx[old_idx]);
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}
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//------------------------------------------------------------------
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// Read a splitting node
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//------------------------------------------------------------------
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else if (strcmp(tag, "split") == 0) { // splitting node
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in >> cd >> cv >> lb >> hb;
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// read low and high subtrees
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ANNkd_ptr lc = annReadTree(in, tree_type, the_pidx, next_idx);
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ANNkd_ptr hc = annReadTree(in, tree_type, the_pidx, next_idx);
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// create new node and return
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return new ANNkd_split(cd, cv, lb, hb, lc, hc);
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}
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//------------------------------------------------------------------
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// Read a shrinking node (bd-tree only)
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//------------------------------------------------------------------
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else if (strcmp(tag, "shrink") == 0) { // shrinking node
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if (tree_type != BD_TREE) {
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annError("Shrinking node not allowed in kd-tree", ANNabort);
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}
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in >> n_bnds; // number of bounding sides
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// allocate bounds array
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ANNorthHSArray bds = new ANNorthHalfSpace[n_bnds];
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for (int i = 0; i < n_bnds; i++) {
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in >> cd >> cv >> sd; // input bounding halfspace
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// copy to array
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bds[i] = ANNorthHalfSpace(cd, cv, sd);
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}
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// read inner and outer subtrees
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ANNkd_ptr ic = annReadTree(in, tree_type, the_pidx, next_idx);
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ANNkd_ptr oc = annReadTree(in, tree_type, the_pidx, next_idx);
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// create new node and return
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return new ANNbd_shrink(n_bnds, bds, ic, oc);
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}
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else {
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annError("Illegal node type in dump file", ANNabort);
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exit(0); // to keep the compiler happy
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}
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}
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