kd_dump.cpp
Go to the documentation of this file.00001 //---------------------------------------------------------------------- 00002 // File: kd_dump.cc 00003 // Programmer: David Mount 00004 // Description: Dump and Load for kd- and bd-trees 00005 // Last modified: 01/04/05 (Version 1.0) 00006 //---------------------------------------------------------------------- 00007 // Copyright (c) 1997-2005 University of Maryland and Sunil Arya and 00008 // David Mount. All Rights Reserved. 00009 // 00010 // This software and related documentation is part of the Approximate 00011 // Nearest Neighbor Library (ANN). This software is provided under 00012 // the provisions of the Lesser GNU Public License (LGPL). See the 00013 // file ../ReadMe.txt for further information. 00014 // 00015 // The University of Maryland (U.M.) and the authors make no 00016 // representations about the suitability or fitness of this software for 00017 // any purpose. It is provided "as is" without express or implied 00018 // warranty. 00019 //---------------------------------------------------------------------- 00020 // History: 00021 // Revision 0.1 03/04/98 00022 // Initial release 00023 // Revision 1.0 04/01/05 00024 // Moved dump out of kd_tree.cc into this file. 00025 // Added kd-tree load constructor. 00026 //---------------------------------------------------------------------- 00027 // This file contains routines for dumping kd-trees and bd-trees and 00028 // reloading them. (It is an abuse of policy to include both kd- and 00029 // bd-tree routines in the same file, sorry. There should be no problem 00030 // in deleting the bd- versions of the routines if they are not 00031 // desired.) 00032 //---------------------------------------------------------------------- 00033 00034 #include <stdlib.h> 00035 #include <string.h> 00036 #include "kd_tree.h" // kd-tree declarations 00037 #include "bd_tree.h" // bd-tree declarations 00038 00039 using namespace std; // make std:: available 00040 00041 //---------------------------------------------------------------------- 00042 // Constants 00043 //---------------------------------------------------------------------- 00044 00045 const int STRING_LEN = 500; // maximum string length 00046 const double EPSILON = 1E-5; // small number for float comparison 00047 00048 enum ANNtreeType {KD_TREE, BD_TREE}; // tree types (used in loading) 00049 00050 //---------------------------------------------------------------------- 00051 // Procedure declarations 00052 //---------------------------------------------------------------------- 00053 00054 static ANNkd_ptr annReadDump( // read dump file 00055 istream &in, // input stream 00056 ANNtreeType tree_type, // type of tree expected 00057 ANNpointArray &the_pts, // new points (if applic) 00058 ANNidxArray &the_pidx, // point indices (returned) 00059 int &the_dim, // dimension (returned) 00060 int &the_n_pts, // number of points (returned) 00061 int &the_bkt_size, // bucket size (returned) 00062 ANNpoint &the_bnd_box_lo, // low bounding point 00063 ANNpoint &the_bnd_box_hi); // high bounding point 00064 00065 static ANNkd_ptr annReadTree( // read tree-part of dump file 00066 istream &in, // input stream 00067 ANNtreeType tree_type, // type of tree expected 00068 ANNidxArray the_pidx, // point indices (modified) 00069 int &next_idx); // next index (modified) 00070 00071 //---------------------------------------------------------------------- 00072 // ANN kd- and bd-tree Dump Format 00073 // The dump file begins with a header containing the version of 00074 // ANN, an optional section containing the points, followed by 00075 // a description of the tree. The tree is printed in preorder. 00076 // 00077 // Format: 00078 // #ANN <version number> <comments> [END_OF_LINE] 00079 // points <dim> <n_pts> (point coordinates: this is optional) 00080 // 0 <xxx> <xxx> ... <xxx> (point indices and coordinates) 00081 // 1 <xxx> <xxx> ... <xxx> 00082 // ... 00083 // tree <dim> <n_pts> <bkt_size> 00084 // <xxx> <xxx> ... <xxx> (lower end of bounding box) 00085 // <xxx> <xxx> ... <xxx> (upper end of bounding box) 00086 // If the tree is null, then a single line "null" is 00087 // output. Otherwise the nodes of the tree are printed 00088 // one per line in preorder. Leaves and splitting nodes 00089 // have the following formats: 00090 // Leaf node: 00091 // leaf <n_pts> <bkt[0]> <bkt[1]> ... <bkt[n-1]> 00092 // Splitting nodes: 00093 // split <cut_dim> <cut_val> <lo_bound> <hi_bound> 00094 // 00095 // For bd-trees: 00096 // 00097 // Shrinking nodes: 00098 // shrink <n_bnds> 00099 // <cut_dim> <cut_val> <side> 00100 // <cut_dim> <cut_val> <side> 00101 // ... (repeated n_bnds times) 00102 //---------------------------------------------------------------------- 00103 00104 void ANNkd_tree::Dump( // dump entire tree 00105 ANNbool with_pts, // print points as well? 00106 ostream &out) // output stream 00107 { 00108 out << "#ANN " << ANNversion << "\n"; 00109 out.precision(ANNcoordPrec); // use full precision in dumping 00110 if (with_pts) { // print point coordinates 00111 out << "points " << dim << " " << n_pts << "\n"; 00112 for (int i = 0; i < n_pts; i++) { 00113 out << i << " "; 00114 annPrintPt(pts[i], dim, out); 00115 out << "\n"; 00116 } 00117 } 00118 out << "tree " // print tree elements 00119 << dim << " " 00120 << n_pts << " " 00121 << bkt_size << "\n"; 00122 00123 annPrintPt(bnd_box_lo, dim, out); // print lower bound 00124 out << "\n"; 00125 annPrintPt(bnd_box_hi, dim, out); // print upper bound 00126 out << "\n"; 00127 00128 if (root == NULL) // empty tree? 00129 out << "null\n"; 00130 else { 00131 root->dump(out); // invoke printing at root 00132 } 00133 out.precision(0); // restore default precision 00134 } 00135 00136 void ANNkd_split::dump( // dump a splitting node 00137 ostream &out) // output stream 00138 { 00139 out << "split " << cut_dim << " " << cut_val << " "; 00140 out << cd_bnds[ANN_LO] << " " << cd_bnds[ANN_HI] << "\n"; 00141 00142 child[ANN_LO]->dump(out); // print low child 00143 child[ANN_HI]->dump(out); // print high child 00144 } 00145 00146 void ANNkd_leaf::dump( // dump a leaf node 00147 ostream &out) // output stream 00148 { 00149 if (this == KD_TRIVIAL) { // canonical trivial leaf node 00150 out << "leaf 0\n"; // leaf no points 00151 } 00152 else{ 00153 out << "leaf " << n_pts; 00154 for (int j = 0; j < n_pts; j++) { 00155 out << " " << bkt[j]; 00156 } 00157 out << "\n"; 00158 } 00159 } 00160 00161 void ANNbd_shrink::dump( // dump a shrinking node 00162 ostream &out) // output stream 00163 { 00164 out << "shrink " << n_bnds << "\n"; 00165 for (int j = 0; j < n_bnds; j++) { 00166 out << bnds[j].cd << " " << bnds[j].cv << " " << bnds[j].sd << "\n"; 00167 } 00168 child[ANN_IN]->dump(out); // print in-child 00169 child[ANN_OUT]->dump(out); // print out-child 00170 } 00171 00172 //---------------------------------------------------------------------- 00173 // Load kd-tree from dump file 00174 // This rebuilds a kd-tree which was dumped to a file. The dump 00175 // file contains all the basic tree information according to a 00176 // preorder traversal. We assume that the dump file also contains 00177 // point data. (This is to guarantee the consistency of the tree.) 00178 // If not, then an error is generated. 00179 // 00180 // Indirectly, this procedure allocates space for points, point 00181 // indices, all nodes in the tree, and the bounding box for the 00182 // tree. When the tree is destroyed, all but the points are 00183 // deallocated. 00184 // 00185 // This routine calls annReadDump to do all the work. 00186 //---------------------------------------------------------------------- 00187 00188 ANNkd_tree::ANNkd_tree( // build from dump file 00189 istream &in) // input stream for dump file 00190 { 00191 int the_dim; // local dimension 00192 int the_n_pts; // local number of points 00193 int the_bkt_size; // local number of points 00194 ANNpoint the_bnd_box_lo; // low bounding point 00195 ANNpoint the_bnd_box_hi; // high bounding point 00196 ANNpointArray the_pts; // point storage 00197 ANNidxArray the_pidx; // point index storage 00198 ANNkd_ptr the_root; // root of the tree 00199 00200 the_root = annReadDump( // read the dump file 00201 in, // input stream 00202 KD_TREE, // expecting a kd-tree 00203 the_pts, // point array (returned) 00204 the_pidx, // point indices (returned) 00205 the_dim, the_n_pts, the_bkt_size, // basic tree info (returned) 00206 the_bnd_box_lo, the_bnd_box_hi); // bounding box info (returned) 00207 00208 // create a skeletal tree 00209 SkeletonTree(the_n_pts, the_dim, the_bkt_size, the_pts, the_pidx); 00210 00211 bnd_box_lo = the_bnd_box_lo; 00212 bnd_box_hi = the_bnd_box_hi; 00213 00214 root = the_root; // set the root 00215 } 00216 00217 ANNbd_tree::ANNbd_tree( // build bd-tree from dump file 00218 istream &in) : ANNkd_tree() // input stream for dump file 00219 { 00220 int the_dim; // local dimension 00221 int the_n_pts; // local number of points 00222 int the_bkt_size; // local number of points 00223 ANNpoint the_bnd_box_lo; // low bounding point 00224 ANNpoint the_bnd_box_hi; // high bounding point 00225 ANNpointArray the_pts; // point storage 00226 ANNidxArray the_pidx; // point index storage 00227 ANNkd_ptr the_root; // root of the tree 00228 00229 the_root = annReadDump( // read the dump file 00230 in, // input stream 00231 BD_TREE, // expecting a bd-tree 00232 the_pts, // point array (returned) 00233 the_pidx, // point indices (returned) 00234 the_dim, the_n_pts, the_bkt_size, // basic tree info (returned) 00235 the_bnd_box_lo, the_bnd_box_hi); // bounding box info (returned) 00236 00237 // create a skeletal tree 00238 SkeletonTree(the_n_pts, the_dim, the_bkt_size, the_pts, the_pidx); 00239 bnd_box_lo = the_bnd_box_lo; 00240 bnd_box_hi = the_bnd_box_hi; 00241 00242 root = the_root; // set the root 00243 } 00244 00245 //---------------------------------------------------------------------- 00246 // annReadDump - read a dump file 00247 // 00248 // This procedure reads a dump file, constructs a kd-tree 00249 // and returns all the essential information needed to actually 00250 // construct the tree. Because this procedure is used for 00251 // constructing both kd-trees and bd-trees, the second argument 00252 // is used to indicate which type of tree we are expecting. 00253 //---------------------------------------------------------------------- 00254 00255 static ANNkd_ptr annReadDump( 00256 istream &in, // input stream 00257 ANNtreeType tree_type, // type of tree expected 00258 ANNpointArray &the_pts, // new points (returned) 00259 ANNidxArray &the_pidx, // point indices (returned) 00260 int &the_dim, // dimension (returned) 00261 int &the_n_pts, // number of points (returned) 00262 int &the_bkt_size, // bucket size (returned) 00263 ANNpoint &the_bnd_box_lo, // low bounding point (ret'd) 00264 ANNpoint &the_bnd_box_hi) // high bounding point (ret'd) 00265 { 00266 int j; 00267 char str[STRING_LEN]; // storage for string 00268 char version[STRING_LEN]; // ANN version number 00269 ANNkd_ptr the_root = NULL; 00270 00271 //------------------------------------------------------------------ 00272 // Input file header 00273 //------------------------------------------------------------------ 00274 in >> str; // input header 00275 if (strcmp(str, "#ANN") != 0) { // incorrect header 00276 annError("Incorrect header for dump file", ANNabort); 00277 } 00278 in.getline(version, STRING_LEN); // get version (ignore) 00279 00280 //------------------------------------------------------------------ 00281 // Input the points 00282 // An array the_pts is allocated and points are read from 00283 // the dump file. 00284 //------------------------------------------------------------------ 00285 in >> str; // get major heading 00286 if (strcmp(str, "points") == 0) { // points section 00287 in >> the_dim; // input dimension 00288 in >> the_n_pts; // number of points 00289 // allocate point storage 00290 the_pts = annAllocPts(the_n_pts, the_dim); 00291 for (int i = 0; i < the_n_pts; i++) { // input point coordinates 00292 ANNidx idx; // point index 00293 in >> idx; // input point index 00294 if (idx < 0 || idx >= the_n_pts) { 00295 annError("Point index is out of range", ANNabort); 00296 } 00297 for (j = 0; j < the_dim; j++) { 00298 in >> the_pts[idx][j]; // read point coordinates 00299 } 00300 } 00301 in >> str; // get next major heading 00302 } 00303 else { // no points were input 00304 annError("Points must be supplied in the dump file", ANNabort); 00305 } 00306 00307 //------------------------------------------------------------------ 00308 // Input the tree 00309 // After the basic header information, we invoke annReadTree 00310 // to do all the heavy work. We create our own array of 00311 // point indices (so we can pass them to annReadTree()) 00312 // but we do not deallocate them. They will be deallocated 00313 // when the tree is destroyed. 00314 //------------------------------------------------------------------ 00315 if (strcmp(str, "tree") == 0) { // tree section 00316 in >> the_dim; // read dimension 00317 in >> the_n_pts; // number of points 00318 in >> the_bkt_size; // bucket size 00319 the_bnd_box_lo = annAllocPt(the_dim); // allocate bounding box pts 00320 the_bnd_box_hi = annAllocPt(the_dim); 00321 00322 for (j = 0; j < the_dim; j++) { // read bounding box low 00323 in >> the_bnd_box_lo[j]; 00324 } 00325 for (j = 0; j < the_dim; j++) { // read bounding box low 00326 in >> the_bnd_box_hi[j]; 00327 } 00328 the_pidx = new ANNidx[the_n_pts]; // allocate point index array 00329 int next_idx = 0; // number of indices filled 00330 // read the tree and indices 00331 the_root = annReadTree(in, tree_type, the_pidx, next_idx); 00332 if (next_idx != the_n_pts) { // didn't see all the points? 00333 annError("Didn't see as many points as expected", ANNwarn); 00334 } 00335 } 00336 else { 00337 annError("Illegal dump format. Expecting section heading", ANNabort); 00338 } 00339 return the_root; 00340 } 00341 00342 //---------------------------------------------------------------------- 00343 // annReadTree - input tree and return pointer 00344 // 00345 // annReadTree reads in a node of the tree, makes any recursive 00346 // calls as needed to input the children of this node (if internal). 00347 // It returns a pointer to the node that was created. An array 00348 // of point indices is given along with a pointer to the next 00349 // available location in the array. As leaves are read, their 00350 // point indices are stored here, and the point buckets point 00351 // to the first entry in the array. 00352 // 00353 // Recall that these are the formats. The tree is given in 00354 // preorder. 00355 // 00356 // Leaf node: 00357 // leaf <n_pts> <bkt[0]> <bkt[1]> ... <bkt[n-1]> 00358 // Splitting nodes: 00359 // split <cut_dim> <cut_val> <lo_bound> <hi_bound> 00360 // 00361 // For bd-trees: 00362 // 00363 // Shrinking nodes: 00364 // shrink <n_bnds> 00365 // <cut_dim> <cut_val> <side> 00366 // <cut_dim> <cut_val> <side> 00367 // ... (repeated n_bnds times) 00368 //---------------------------------------------------------------------- 00369 00370 static ANNkd_ptr annReadTree( 00371 istream &in, // input stream 00372 ANNtreeType tree_type, // type of tree expected 00373 ANNidxArray the_pidx, // point indices (modified) 00374 int &next_idx) // next index (modified) 00375 { 00376 char tag[STRING_LEN]; // tag (leaf, split, shrink) 00377 int n_pts; // number of points in leaf 00378 int cd; // cut dimension 00379 ANNcoord cv; // cut value 00380 ANNcoord lb; // low bound 00381 ANNcoord hb; // high bound 00382 int n_bnds; // number of bounding sides 00383 int sd; // which side 00384 00385 in >> tag; // input node tag 00386 00387 if (strcmp(tag, "null") == 0) { // null tree 00388 return NULL; 00389 } 00390 //------------------------------------------------------------------ 00391 // Read a leaf 00392 //------------------------------------------------------------------ 00393 if (strcmp(tag, "leaf") == 0) { // leaf node 00394 00395 in >> n_pts; // input number of points 00396 int old_idx = next_idx; // save next_idx 00397 if (n_pts == 0) { // trivial leaf 00398 return KD_TRIVIAL; 00399 } 00400 else { 00401 for (int i = 0; i < n_pts; i++) { // input point indices 00402 in >> the_pidx[next_idx++]; // store in array of indices 00403 } 00404 } 00405 return new ANNkd_leaf(n_pts, &the_pidx[old_idx]); 00406 } 00407 //------------------------------------------------------------------ 00408 // Read a splitting node 00409 //------------------------------------------------------------------ 00410 else if (strcmp(tag, "split") == 0) { // splitting node 00411 00412 in >> cd >> cv >> lb >> hb; 00413 00414 // read low and high subtrees 00415 ANNkd_ptr lc = annReadTree(in, tree_type, the_pidx, next_idx); 00416 ANNkd_ptr hc = annReadTree(in, tree_type, the_pidx, next_idx); 00417 // create new node and return 00418 return new ANNkd_split(cd, cv, lb, hb, lc, hc); 00419 } 00420 //------------------------------------------------------------------ 00421 // Read a shrinking node (bd-tree only) 00422 //------------------------------------------------------------------ 00423 else if (strcmp(tag, "shrink") == 0) { // shrinking node 00424 if (tree_type != BD_TREE) { 00425 annError("Shrinking node not allowed in kd-tree", ANNabort); 00426 } 00427 00428 in >> n_bnds; // number of bounding sides 00429 // allocate bounds array 00430 ANNorthHSArray bds = new ANNorthHalfSpace[n_bnds]; 00431 for (int i = 0; i < n_bnds; i++) { 00432 in >> cd >> cv >> sd; // input bounding halfspace 00433 // copy to array 00434 bds[i] = ANNorthHalfSpace(cd, cv, sd); 00435 } 00436 // read inner and outer subtrees 00437 ANNkd_ptr ic = annReadTree(in, tree_type, the_pidx, next_idx); 00438 ANNkd_ptr oc = annReadTree(in, tree_type, the_pidx, next_idx); 00439 // create new node and return 00440 return new ANNbd_shrink(n_bnds, bds, ic, oc); 00441 } 00442 else { 00443 annError("Illegal node type in dump file", ANNabort); 00444 exit(0); // to keep the compiler happy 00445 } 00446 }