1 /* $NetBSD: graph2.h,v 1.2 2021/01/07 16:03:08 joerg Exp $ */
2 /*-
3 * Copyright (c) 2009 The NetBSD Foundation, Inc.
4 * All rights reserved.
5 *
6 * This code is derived from software contributed to The NetBSD Foundation
7 * by Joerg Sonnenberger.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 /*
35 * Implementation of common 2/3-graph routines:
36 * - build a 2/3-graph with hash-pairs as edges
37 * - check a 2/3-graph for acyclicness and compute an output order
38 *
39 * For each vertex in the 2/3-graph, the incidence lists need to kept.
40 * Avoid storing the full list by just XORing the indices of the still
41 * incident edges and the number of such edges as that's all the peeling
42 * computation needs. This is inspired by:
43 * Cache-Oblivious Peeling of Random Hypergraphs by Djamal Belazzougui,
44 * Paolo Boldi, Giuseppe Ottaviano, Rossano Venturini, and Sebastiano
45 * Vigna. https://arxiv.org/abs/1312.0526
46 *
47 * Unlike in the paper, we don't care about external storage and have
48 * the edge list at hand all the time. As such, no ordering is necessary
49 * and the vertices of the edge don't have to be copied.
50 *
51 * The core observation of the paper above is that for a degree of one,
52 * the incident edge can be obtained directly.
53 */
54
55 #ifndef GRAPH_SIZE
56 #define GRAPH_SIZE 2
57 #endif
58
59 #define SIZED__(n, i) n ## i
60 #define SIZED_(n, i) SIZED__(n, i)
61 #define SIZED(n) SIZED_(n, GRAPH_SIZE)
62 #define SIZED2__(n, i, m) n ## i ## m
63 #define SIZED2_(n, i, m) SIZED2__(n, i, m)
64 #define SIZED2(n) SIZED2_(graph, GRAPH_SIZE, n)
65
SIZED(vertex)66 struct SIZED(vertex) {
67 uint32_t degree, edges;
68 };
69
SIZED(edge)70 struct SIZED(edge) {
71 uint32_t vertices[GRAPH_SIZE];
72 };
73
SIZED(graph)74 struct SIZED(graph) {
75 struct SIZED(vertex) *verts;
76 struct SIZED(edge) *edges;
77 uint32_t output_index;
78 uint32_t *output_order;
79 uint8_t *visited;
80 uint32_t e, v;
81 int hash_fudge;
82 };
83
84 void SIZED2(_setup)(struct SIZED(graph) *, uint32_t, uint32_t);
85 void SIZED2(_free)(struct SIZED(graph) *);
86
87 int SIZED2(_hash)(struct nbperf *, struct SIZED(graph) *);
88 int SIZED2(_output_order)(struct SIZED(graph) *graph);
89