PostGIS  2.5.0dev-r@@SVN_REVISION@@
static void test_kmeans ( void  )
static

Definition at line 1313 of file cu_algorithm.c.

References lwalloc(), lwfree(), lwgeom_cluster_2d_kmeans(), lwgeom_free(), lwpoint_as_lwgeom(), lwpoint_make2d(), r, and SRID_UNKNOWN.

Referenced by algorithms_suite_setup().

1314 {
1315  static int cluster_size = 100;
1316  static int num_clusters = 4;
1317  static double spread = 1.5;
1318  int N = cluster_size * num_clusters;
1319  LWGEOM **geoms;
1320  int i, j, k=0;
1321  int *r;
1322 
1323  geoms = lwalloc(sizeof(LWGEOM*) * N);
1324 
1325  for (j = 0; j < num_clusters; j++) {
1326  for (i = 0; i < cluster_size; i++)
1327  {
1328  double u1 = 1.0 * rand() / RAND_MAX;
1329  double u2 = 1.0 * rand() / RAND_MAX;
1330  double z1 = spread * j + sqrt(-2*log2(u1))*cos(2*M_PI*u2);
1331  double z2 = spread * j + sqrt(-2*log2(u1))*sin(2*M_PI*u2);
1332 
1333  LWPOINT *lwp = lwpoint_make2d(SRID_UNKNOWN, z1, z2);
1334  geoms[k++] = lwpoint_as_lwgeom(lwp);
1335  }
1336  }
1337 
1338  r = lwgeom_cluster_2d_kmeans((const LWGEOM **)geoms, N, num_clusters);
1339 
1340  // for (i = 0; i < k; i++)
1341  // {
1342  // printf("[%d] %s\n", r[i], lwgeom_to_ewkt(geoms[i]));
1343  // }
1344 
1345  /* Clean up */
1346  lwfree(r);
1347  for (i = 0; i < k; i++)
1348  lwgeom_free(geoms[i]);
1349  lwfree(geoms);
1350 
1351  return;
1352 }
char * r
Definition: cu_in_wkt.c:24
void lwfree(void *mem)
Definition: lwutil.c:244
LWPOINT * lwpoint_make2d(int srid, double x, double y)
Definition: lwpoint.c:163
void lwgeom_free(LWGEOM *geom)
Definition: lwgeom.c:1137
#define SRID_UNKNOWN
Unknown SRID value.
Definition: liblwgeom.h:187
int * lwgeom_cluster_2d_kmeans(const LWGEOM **geoms, uint32_t ngeoms, uint32_t k)
Take a list of LWGEOMs and a number of clusters and return an integer array indicating which cluster ...
Definition: lwkmeans.c:127
LWGEOM * lwpoint_as_lwgeom(const LWPOINT *obj)
Definition: lwgeom.c:334
void * lwalloc(size_t size)
Definition: lwutil.c:229

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