279 lines
9.8 KiB
C
279 lines
9.8 KiB
C
/***********************************************************************
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* Software License Agreement (BSD License)
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*
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* Copyright 2008-2009 Marius Muja (mariusm@cs.ubc.ca). All rights reserved.
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* Copyright 2008-2009 David G. Lowe (lowe@cs.ubc.ca). All rights reserved.
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*
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* THE BSD LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*************************************************************************/
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#ifndef FLANN_H
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#define FLANN_H
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#include "constants.h"
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#ifdef WIN32
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/* win32 dll export/import directives */
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#ifdef flann_EXPORTS
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#define LIBSPEC __declspec(dllexport)
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#else
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#define LIBSPEC __declspec(dllimport)
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#endif
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#else
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/* unix needs nothing */
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#define LIBSPEC
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#endif
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struct FLANNParameters {
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flann_algorithm_t algorithm; // the algorithm to use (see constants.h)
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int checks; // how many leafs (features) to check in one search
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float cb_index; // cluster boundary index. Used when searching the kmeans tree
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int trees; // number of randomized trees to use (for kdtree)
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int branching; // branching factor (for kmeans tree)
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int iterations; // max iterations to perform in one kmeans cluetering (kmeans tree)
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flann_centers_init_t centers_init; // algorithm used for picking the initial cluetr centers for kmeans tree
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float target_precision; // precision desired (used for autotuning, -1 otherwise)
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float build_weight; // build tree time weighting factor
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float memory_weight; // index memory weigthing factor
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float sample_fraction; // what fraction of the dataset to use for autotuning
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flann_log_level_t log_level; // determines the verbosity of each flann function
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char* log_destination; // file where the output should go, NULL for the console
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long random_seed; // random seed to use
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};
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typedef void* FLANN_INDEX; // deprecated
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typedef void* flann_index_t;
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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Sets the log level used for all flann functions (unless
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specified in FLANNParameters for each call
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Params:
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level = verbosity level (defined in constants.h)
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*/
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LIBSPEC void flann_log_verbosity(int level);
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/**
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* Sets the distance type to use throughout FLANN.
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* If distance type specified is MINKOWSKI, the second argument
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* specifies which order the minkowski distance should have.
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*/
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LIBSPEC void flann_set_distance_type(flann_distance_t distance_type, int order);
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/**
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Builds and returns an index. It uses autotuning if the target_precision field of index_params
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is between 0 and 1, or the parameters specified if it's -1.
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Params:
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dataset = pointer to a data set stored in row major order
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rows = number of rows (features) in the dataset
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cols = number of columns in the dataset (feature dimensionality)
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speedup = speedup over linear search, estimated if using autotuning, output parameter
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index_params = index related parameters
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flann_params = generic flann parameters
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Returns: the newly created index or a number <0 for error
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*/
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LIBSPEC FLANN_INDEX flann_build_index(float* dataset,
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int rows,
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int cols,
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float* speedup,
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struct FLANNParameters* flann_params);
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/**
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* Saves the index to a file. Only the index is saved into the file, the dataset corresponding to the index is not saved.
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*
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* @param index_id The index that should be saved
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* @param filename The filename the index should be saved to
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* @return Returns 0 on success, negative value on error.
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*/
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LIBSPEC int flann_save_index(FLANN_INDEX index_id,
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char* filename);
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/**
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* Loads an index from a file.
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*
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* @param filename File to load the index from.
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* @param dataset The dataset corresponding to the index.
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* @param rows Dataset tors
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* @param cols Dataset columns
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* @return
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*/
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LIBSPEC FLANN_INDEX flann_load_index(char* filename,
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float* dataset,
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int rows,
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int cols);
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/**
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Builds an index and uses it to find nearest neighbors.
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Params:
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dataset = pointer to a data set stored in row major order
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rows = number of rows (features) in the dataset
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cols = number of columns in the dataset (feature dimensionality)
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testset = pointer to a query set stored in row major order
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trows = number of rows (features) in the query dataset (same dimensionality as features in the dataset)
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indices = pointer to matrix for the indices of the nearest neighbors of the testset features in the dataset
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(must have trows number of rows and nn number of columns)
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nn = how many nearest neighbors to return
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index_params = index related parameters
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flann_params = generic flann parameters
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Returns: zero or -1 for error
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*/
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LIBSPEC int flann_find_nearest_neighbors(float* dataset,
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int rows,
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int cols,
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float* testset,
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int trows,
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int* indices,
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float* dists,
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int nn,
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struct FLANNParameters* flann_params);
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/**
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Searches for nearest neighbors using the index provided
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Params:
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index_id = the index (constructed previously using flann_build_index).
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testset = pointer to a query set stored in row major order
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trows = number of rows (features) in the query dataset (same dimensionality as features in the dataset)
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indices = pointer to matrix for the indices of the nearest neighbors of the testset features in the dataset
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(must have trows number of rows and nn number of columns)
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nn = how many nearest neighbors to return
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checks = number of checks to perform before the search is stopped
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flann_params = generic flann parameters
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Returns: zero or a number <0 for error
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*/
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LIBSPEC int flann_find_nearest_neighbors_index(FLANN_INDEX index_id,
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float* testset,
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int trows,
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int* indices,
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float* dists,
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int nn,
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int checks,
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struct FLANNParameters* flann_params);
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/**
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* Performs an radius search using an already constructed index.
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*
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* In case of radius search, instead of always returning a predetermined
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* number of nearest neighbours (for example the 10 nearest neighbours), the
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* search will return all the neighbours found within a search radius
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* of the query point.
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*
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* The check parameter in the function below sets the level of approximation
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* for the search by only visiting "checks" number of features in the index
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* (the same way as for the KNN search). A lower value for checks will give
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* a higher search speedup at the cost of potentially not returning all the
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* neighbours in the specified radius.
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*/
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LIBSPEC int flann_radius_search(FLANN_INDEX index_ptr, /* the index */
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float* query, /* query point */
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int* indices, /* array for storing the indices found (will be modified) */
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float* dists, /* similar, but for storing distances */
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int max_nn, /* size of arrays indices and dists */
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float radius, /* search radius (squared radius for euclidian metric) */
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int checks, /* number of features to check, sets the level of approximation */
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FLANNParameters* flann_params);
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/**
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Deletes an index and releases the memory used by it.
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Params:
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index_id = the index (constructed previously using flann_build_index).
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flann_params = generic flann parameters
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Returns: zero or a number <0 for error
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*/
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LIBSPEC int flann_free_index(FLANN_INDEX index_id,
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struct FLANNParameters* flann_params);
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/**
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Clusters the features in the dataset using a hierarchical kmeans clustering approach.
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This is significantly faster than using a flat kmeans clustering for a large number
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of clusters.
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Params:
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dataset = pointer to a data set stored in row major order
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rows = number of rows (features) in the dataset
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cols = number of columns in the dataset (feature dimensionality)
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clusters = number of cluster to compute
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result = memory buffer where the output cluster centers are storred
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index_params = used to specify the kmeans tree parameters (branching factor, max number of iterations to use)
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flann_params = generic flann parameters
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Returns: number of clusters computed or a number <0 for error. This number can be different than the number of clusters requested, due to the
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way hierarchical clusters are computed. The number of clusters returned will be the highest number of the form
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(branch_size-1)*K+1 smaller than the number of clusters requested.
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*/
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LIBSPEC int flann_compute_cluster_centers(float* dataset,
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int rows,
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int cols,
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int clusters,
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float* result,
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struct FLANNParameters* flann_params);
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#ifdef __cplusplus
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};
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#include "flann.hpp"
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#endif
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#endif /*FLANN_H*/
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