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ehein6ehein6
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Added BFS implementations to stinger_alg.
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3 files changed

Lines changed: 188 additions & 0 deletions

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‎lib/stinger_alg/CMakeLists.txt‎

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set(sources
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src/adamic_adar.c
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src/betweenness.c
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src/bfs.c
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src/clustering.c
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src/kcore.c
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src/pagerank.c
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set(headers
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inc/adamic_adar.h
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inc/betweenness.h
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inc/bfs.h
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inc/clustering.h
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inc/kcore.h
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inc/pagerank.h

‎lib/stinger_alg/inc/bfs.h‎

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#ifndef STINGER_BFS_H_
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#define STINGER_BFS_H_
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#include "stinger_core/stinger.h"
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#include "stinger_core/xmalloc.h"
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#include "stinger_core/stinger_error.h"
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int64_t
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parallel_breadth_first_search (
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struct stinger * S,
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int64_t nv,
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int64_t source,
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int64_t * marks,
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int64_t * queue,
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int64_t * Qhead,
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int64_t * level
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);
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int64_t
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direction_optimizing_parallel_breadth_first_search (
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struct stinger * S,
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int64_t nv,
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int64_t source,
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int64_t * marks,
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int64_t * queue,
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int64_t * Qhead,
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int64_t * level
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);
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#endif

‎lib/stinger_alg/src/bfs.c‎

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#include "bfs.h"
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#include "stinger_core/x86_full_empty.h"
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int64_t
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parallel_breadth_first_search (struct stinger * S, int64_t nv,
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int64_t source, int64_t * marks,
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int64_t * queue, int64_t * Qhead, int64_t * level)
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{
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for (int64_t i = 0; i < nv; i++) {
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level[i] = -1;
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marks[i] = 0;
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}
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int64_t nQ, Qnext, Qstart, Qend;
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/* initialize */
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queue[0] = source;
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level[source] = 0;
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marks[source] = 1;
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Qnext = 1; /* next open slot in the queue */
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nQ = 1; /* level we are currently processing */
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Qhead[0] = 0; /* beginning of the current frontier */
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Qhead[1] = 1; /* end of the current frontier */
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Qstart = Qhead[nQ-1];
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Qend = Qhead[nQ];
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while (Qstart != Qend) {
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OMP ("omp parallel for")
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for (int64_t j = Qstart; j < Qend; j++) {
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STINGER_FORALL_OUT_EDGES_OF_VTX_BEGIN (S, queue[j]) {
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int64_t d = level[STINGER_EDGE_DEST];
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if (d < 0) {
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if (stinger_int64_fetch_add (&marks[STINGER_EDGE_DEST], 1) == 0) {
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level[STINGER_EDGE_DEST] = nQ;
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int64_t mine = stinger_int64_fetch_add(&Qnext, 1);
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queue[mine] = STINGER_EDGE_DEST;
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}
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}
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} STINGER_FORALL_OUT_EDGES_OF_VTX_END();
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}
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Qstart = Qhead[nQ-1];
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Qend = Qnext;
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Qhead[nQ++] = Qend;
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}
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return nQ;
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}
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int64_t
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direction_optimizing_parallel_breadth_first_search (struct stinger * S, int64_t nv,
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int64_t source, int64_t * marks,
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int64_t * queue, int64_t * Qhead, int64_t * level)
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{
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for (int64_t i = 0; i < nv; i++) {
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level[i] = -1;
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marks[i] = 0;
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}
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int64_t nQ, Qnext, Qstart, Qend;
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int64_t mf = 0; /* number of edges incident on frontier */
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int64_t nf = 0; /* number of vertices in frontier */
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int64_t mu = 0; /* number of edges incident on unexplored vertices */
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int64_t nf_last = 0; /* size of previous frontier */
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/* initialize */
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queue[0] = source;
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level[source] = 0;
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marks[source] = 1;
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Qnext = 1; /* next open slot in the queue */
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nQ = 1; /* level we are currently processing */
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Qhead[0] = 0; /* beginning of the current frontier */
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Qhead[1] = 1; /* end of the current frontier */
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Qstart = Qhead[nQ-1];
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Qend = Qhead[nQ];
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mf = 0;
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nf = 0;
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mu = stinger_total_edges(S);
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//printf("mf: %ld, nf: %ld, mu: %ld, nf_last: %ld\n", mf, nf, mu, nf_last);
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int64_t top_down = 1;
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while (Qstart != Qend) {
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if (top_down) {
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/* forward (top down) traversal */
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OMP ("omp parallel for")
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for (int64_t j = Qstart; j < Qend; j++) {
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STINGER_FORALL_OUT_EDGES_OF_VTX_BEGIN (S, queue[j]) {
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int64_t d = level[STINGER_EDGE_DEST];
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if (d < 0) {
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if (stinger_int64_fetch_add (&marks[STINGER_EDGE_DEST], 1) == 0) {
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level[STINGER_EDGE_DEST] = nQ;
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int64_t mine = stinger_int64_fetch_add(&Qnext, 1);
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queue[mine] = STINGER_EDGE_DEST;
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}
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}
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} STINGER_FORALL_OUT_EDGES_OF_VTX_END();
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}
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} else {
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/* reverse (bottom up) traversal */
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OMP ("omp parallel for")
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for (int64_t i = 0; i < nv; i++) {
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int64_t done = 0;
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/* only process unvisited vertices */
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if (!marks[i]) {
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STINGER_FORALL_OUT_EDGES_OF_VTX_BEGIN (S, i) {
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/* neighbor has been visited */
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if (!done && level[STINGER_EDGE_DEST] == nQ-1) {
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level[i] = nQ;
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marks[i] = 1;
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/* if we don't queue here, we cannot restart the forward search */
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int64_t mine = stinger_int64_fetch_add(&Qnext, 1);
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queue[mine] = i;
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done = 1;
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}
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} STINGER_FORALL_OUT_EDGES_OF_VTX_END();
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}
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}
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}
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Qstart = Qhead[nQ-1];
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Qend = Qnext;
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Qhead[nQ++] = Qend;
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/* calculate new transition parameters */
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nf_last = nf;
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nf = Qend - Qstart;
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mf = 0;
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OMP ("omp parallel for reduction(+:mf) reduction(-:mu)")
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for (int64_t j = Qstart; j < Qend; j++) {
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int64_t deg_j = stinger_outdegree_get(S, queue[j]);
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mf += deg_j;
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mu -= deg_j;
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}
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//printf("mf: %ld, nf: %ld, mu: %ld, nf_last: %ld\n", mf, nf, mu, nf_last);
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/* evaluate the transition state machine */
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if (top_down) {
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if (mf > (mu / 14) && (nf - nf_last > 0)) {
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top_down = 0;
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}
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} else {
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if (nf < (nv / 24) && (nf - nf_last < 0)) {
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top_down = 1;
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}
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}
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} /* end while */
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return nQ;
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}

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