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