PostGIS 3.0.6dev-r@@SVN_REVISION@@
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◆ test_kmeans()

static void test_kmeans ( void  )
static

Definition at line 1704 of file cu_algorithm.c.

1705{
1706 static int cluster_size = 100;
1707 static int num_clusters = 4;
1708 static double spread = 1.5;
1709 int N = cluster_size * num_clusters;
1710 LWGEOM **geoms;
1711 int i, j, k=0;
1712 int *r;
1713
1714 geoms = lwalloc(sizeof(LWGEOM*) * N);
1715
1716 for (j = 0; j < num_clusters; j++) {
1717 for (i = 0; i < cluster_size; i++)
1718 {
1719 double u1 = 1.0 * rand() / RAND_MAX;
1720 double u2 = 1.0 * rand() / RAND_MAX;
1721 double z1 = spread * j + sqrt(-2*log2(u1))*cos(2*M_PI*u2);
1722 double z2 = spread * j + sqrt(-2*log2(u1))*sin(2*M_PI*u2);
1723
1724 LWPOINT *lwp = lwpoint_make2d(SRID_UNKNOWN, z1, z2);
1725 geoms[k++] = lwpoint_as_lwgeom(lwp);
1726 }
1727 }
1728
1729 r = lwgeom_cluster_2d_kmeans((const LWGEOM **)geoms, N, num_clusters);
1730
1731 // for (i = 0; i < k; i++)
1732 // {
1733 // printf("[%d] %s\n", r[i], lwgeom_to_ewkt(geoms[i]));
1734 // }
1735
1736 /* Clean up */
1737 lwfree(r);
1738 for (i = 0; i < k; i++)
1739 lwgeom_free(geoms[i]);
1740 lwfree(geoms);
1741
1742 return;
1743}
char * r
Definition cu_in_wkt.c:24
LWGEOM * lwpoint_as_lwgeom(const LWPOINT *obj)
Definition lwgeom.c:326
void lwgeom_free(LWGEOM *geom)
Definition lwgeom.c:1138
void * lwalloc(size_t size)
Definition lwutil.c:227
void lwfree(void *mem)
Definition lwutil.c:242
LWPOINT * lwpoint_make2d(int32_t srid, double x, double y)
Definition lwpoint.c:163
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:244
#define SRID_UNKNOWN
Unknown SRID value.
Definition liblwgeom.h:229

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

Referenced by algorithms_suite_setup().

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