#include <flann/flann.h>

#include <stdio.h>

#include <stdlib.h>

float* read_points(const char* filename, int rows, int cols)

{

float* data;

float *p;

FILE* fin;

int i,j;

fin = fopen(filename,"r");

if (!fin) {

printf("Cannot open input file.\n");

exit(1);

}

data = (float*) malloc(rows*cols*sizeof(float));

if (!data) {

printf("Cannot allocate memory.\n");

exit(1);

}

p = data;

for (i=0;i<rows;++i) {

for (j=0;j<cols;++j) {

if(fscanf(fin,"%g ",p) != 1) {

printf("Input file is incorrectly formatted.\n");

exit(1);

}

}

}

fclose(fin);

return data;

}

void write_results(const char* filename, int *data, int rows, int cols)

{

FILE* fout;

int* p;

int i,j;

fout = fopen(filename,"w");

if (!fout) {

printf("Cannot open output file.\n");

exit(1);

}

p = data;

for (i=0;i<rows;++i) {

for (j=0;j<cols;++j) {

fprintf(fout,"%d ",*p);

p++;

}

fprintf(fout,"\n");

}

fclose(fout);

}

int main(int argc, char** argv)

{

float* dataset;

float* testset;

int nn;

int* result;

float* dists;

struct FLANNParameters p;

float speedup;

flann_index_t index_id;

int rows = 9000;

int cols = 128;

int tcount = 1000;

/*

* The files dataset.dat and testset.dat can be downloaded from:

* http://people.cs.ubc.ca/~mariusm/uploads/FLANN/datasets/dataset.dat

* http://people.cs.ubc.ca/~mariusm/uploads/FLANN/datasets/testset.dat

*/

printf("Reading input data file.\n");

dataset = read_points("dataset.dat", rows, cols);

printf("Reading test data file.\n");

testset = read_points("testset.dat", tcount, cols);

nn = 3;

result = (int*) malloc(tcount*nn*sizeof(int));

dists = (float*) malloc(tcount*nn*sizeof(float));

p = DEFAULT_FLANN_PARAMETERS;

p.algorithm = FLANN_INDEX_KDTREE;

p.trees = 8;

p.log_level = FLANN_LOG_INFO;

p.checks = 64;

printf("Computing index.\n");

index_id = flann_build_index(dataset, rows, cols, &speedup, &p);

flann_find_nearest_neighbors_index(index_id, testset, tcount, result, dists, nn, &p);

write_results("results.dat",result, tcount, nn);

flann_free_index(index_id, &p);

free(dataset);

free(testset);

free(result);

free(dists);

return 0;

}