File: cu_unionfind.c

package info (click to toggle)
postgis 3.5.2%2Bdfsg-1
  • links: PTS, VCS
  • area: main
  • in suites: sid, trixie
  • size: 70,052 kB
  • sloc: ansic: 162,204; sql: 93,950; xml: 53,121; cpp: 12,646; perl: 5,658; sh: 5,369; makefile: 3,434; python: 1,205; yacc: 447; lex: 151; pascal: 58
file content (174 lines) | stat: -rw-r--r-- 4,653 bytes parent folder | download | duplicates (5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * Copyright 2015 Daniel Baston
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU General Public Licence. See the COPYING file.
 *
 **********************************************************************/

#include "CUnit/Basic.h"

#include "../lwunionfind.h"
#include "cu_tester.h"

static void test_unionfind_create(void)
{
	UNIONFIND *uf = UF_create(10);

	uint32_t expected_initial_ids[] =   { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
	uint32_t expected_initial_sizes[] = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };

	ASSERT_INT_EQUAL(uf->N, 10);
	ASSERT_INT_EQUAL(uf->num_clusters, 10);
	ASSERT_INTARRAY_EQUAL(uf->clusters, expected_initial_ids, 10);
	ASSERT_INTARRAY_EQUAL(uf->cluster_sizes, expected_initial_sizes, 10);

	UF_destroy(uf);
}

static void test_unionfind_union(void)
{
	UNIONFIND *uf = UF_create(10);

	UF_union(uf, 0, 7); /* both have size = 1, so 7 becomes 0 */
	UF_union(uf, 3, 2); /* both have size = 1, so 3 becomes 2 */
	UF_union(uf, 8, 7); /* add 8 (smaller) to 0-7 (larger)    */
	UF_union(uf, 1, 2); /* add 1 (smaller) to 2-3 (larger)    */

	uint32_t expected_final_ids[] =   { 0, 2, 2, 2, 4, 5, 6, 0, 0, 9 };
	uint32_t expected_final_sizes[] = { 3, 0, 3, 0, 1, 1, 1, 0, 0, 1 };

	ASSERT_INT_EQUAL(uf->N, 10);
	ASSERT_INT_EQUAL(uf->num_clusters, 6);
	ASSERT_INTARRAY_EQUAL(uf->clusters, expected_final_ids, 10);
	ASSERT_INTARRAY_EQUAL(uf->cluster_sizes, expected_final_sizes, 10);

	UF_destroy(uf);
}

static void test_unionfind_ordered_by_cluster(void)
{
	uint32_t final_clusters[] = { 0, 2, 2, 2, 4, 5, 6, 0, 0, 2 };
	uint32_t final_sizes[]    = { 3, 0, 4, 0, 1, 1, 1, 0, 0, 0 };

	/* Manually create UF at desired final state */
	UNIONFIND uf =
	{
		.N = 10,
		.num_clusters = 5,
		.clusters = final_clusters,
		.cluster_sizes = final_sizes
	};

	uint32_t* ids_by_cluster = UF_ordered_by_cluster(&uf);

	char encountered_cluster[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

	uint32_t i;
	for (i = 0; i < uf.N; i++)
	{
		uint32_t c = final_clusters[ids_by_cluster[i]];
		if (!encountered_cluster[c])
		{
			encountered_cluster[c] = 1;
		}
		else
		{
			/* If we've seen an element of this cluster before, then the
			 * current cluster must be the same as the previous cluster. */
			uint32_t c_prev = final_clusters[ids_by_cluster[i-1]];
			CU_ASSERT_EQUAL(c, c_prev);
		}
	}
	lwfree(ids_by_cluster);
}

static void test_unionfind_path_compression(void)
{
	UNIONFIND* uf = UF_create(5);
	uint32_t i;

	uf->clusters[1] = 0;
	uf->clusters[2] = 1;
	uf->clusters[3] = 2;
	uf->clusters[4] = 3;

	/* Calling "find" on a leaf should attach all nodes between the root and the
	 * leaf directly to the root. */
	uint32_t root = UF_find(uf, 4);
	for (i = 0; i < uf->N; i++)
	{
		/* Verify that all cluster references have been updated to point
		 * directly to the root. */
		CU_ASSERT_EQUAL(root, uf->clusters[i]);
	}

	UF_destroy(uf);
}

static void test_unionfind_collapse_cluster_ids(void)
{
	UNIONFIND* uf = UF_create(10);

	uf->clusters[0] = 8;
	uf->clusters[1] = 5;
	uf->clusters[2] = 5;
	uf->clusters[3] = 5;
	uf->clusters[4] = 7;
	uf->clusters[5] = 5;
	uf->clusters[6] = 8;
	uf->clusters[7] = 7;
	uf->clusters[8] = 8;
	uf->clusters[9] = 7;

	uf->cluster_sizes[0] = 3;
	uf->cluster_sizes[1] = 4;
	uf->cluster_sizes[2] = 4;
	uf->cluster_sizes[3] = 4;
	uf->cluster_sizes[4] = 3;
	uf->cluster_sizes[5] = 4;
	uf->cluster_sizes[6] = 3;
	uf->cluster_sizes[7] = 3;
	uf->cluster_sizes[8] = 3;
	uf->cluster_sizes[9] = 3;

	/* 5 -> 0
	 * 7 -> 1
	 * 8 -> 2
	 */
	uint32_t expected_collapsed_ids[] = { 2, 0, 0, 0, 1, 0, 2, 1, 2, 1 };
	uint32_t* collapsed_ids = UF_get_collapsed_cluster_ids(uf, NULL);

	ASSERT_INTARRAY_EQUAL(collapsed_ids, expected_collapsed_ids, 10);

	lwfree(collapsed_ids);

	char is_in_cluster[] = { 0, 1, 1, 1, 0, 1, 0, 0, 0, 0 };
	uint32_t expected_collapsed_ids2[] = { 8, 0, 0, 0, 7, 0, 8, 7, 8, 7 };

	collapsed_ids = UF_get_collapsed_cluster_ids(uf, is_in_cluster);
	uint32_t i;
	for (i = 0; i < uf->N; i++)
	{
		if (is_in_cluster[i])
			ASSERT_INT_EQUAL(expected_collapsed_ids2[i], collapsed_ids[i]);
	}

	lwfree(collapsed_ids);
	UF_destroy(uf);
}

void unionfind_suite_setup(void);
void unionfind_suite_setup(void)
{
	CU_pSuite suite = CU_add_suite("clustering_unionfind", NULL, NULL);
	PG_ADD_TEST(suite, test_unionfind_create);
	PG_ADD_TEST(suite, test_unionfind_union);
	PG_ADD_TEST(suite, test_unionfind_ordered_by_cluster);
	PG_ADD_TEST(suite, test_unionfind_path_compression);
	PG_ADD_TEST(suite, test_unionfind_collapse_cluster_ids);
}