PostGIS  2.5.7dev-r@@SVN_REVISION@@

◆ test_kmeans()

static void test_kmeans ( void  )
static

Definition at line 1413 of file cu_algorithm.c.

1414 {
1415  static int cluster_size = 100;
1416  static int num_clusters = 4;
1417  static double spread = 1.5;
1418  int N = cluster_size * num_clusters;
1419  LWGEOM **geoms;
1420  int i, j, k=0;
1421  int *r;
1422 
1423  geoms = lwalloc(sizeof(LWGEOM*) * N);
1424 
1425  for (j = 0; j < num_clusters; j++) {
1426  for (i = 0; i < cluster_size; i++)
1427  {
1428  double u1 = 1.0 * rand() / RAND_MAX;
1429  double u2 = 1.0 * rand() / RAND_MAX;
1430  double z1 = spread * j + sqrt(-2*log2(u1))*cos(2*M_PI*u2);
1431  double z2 = spread * j + sqrt(-2*log2(u1))*sin(2*M_PI*u2);
1432 
1433  LWPOINT *lwp = lwpoint_make2d(SRID_UNKNOWN, z1, z2);
1434  geoms[k++] = lwpoint_as_lwgeom(lwp);
1435  }
1436  }
1437 
1438  r = lwgeom_cluster_2d_kmeans((const LWGEOM **)geoms, N, num_clusters);
1439 
1440  // for (i = 0; i < k; i++)
1441  // {
1442  // printf("[%d] %s\n", r[i], lwgeom_to_ewkt(geoms[i]));
1443  // }
1444 
1445  /* Clean up */
1446  lwfree(r);
1447  for (i = 0; i < k; i++)
1448  lwgeom_free(geoms[i]);
1449  lwfree(geoms);
1450 
1451  return;
1452 }
char * r
Definition: cu_in_wkt.c:24
LWPOINT * lwpoint_make2d(int srid, double x, double y)
Definition: lwpoint.c:163
void lwgeom_free(LWGEOM *geom)
Definition: lwgeom.c:1144
void lwfree(void *mem)
Definition: lwutil.c:244
LWGEOM * lwpoint_as_lwgeom(const LWPOINT *obj)
Definition: lwgeom.c:335
void * lwalloc(size_t size)
Definition: lwutil.c:229
#define SRID_UNKNOWN
Unknown SRID value.
Definition: liblwgeom.h:188
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:240

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

Referenced by algorithms_suite_setup().

Here is the call graph for this function:
Here is the caller graph for this function: