FM / gvpr

/usr/share/graphviz/gvpr

Name	Size	Mode	Actions
addedges	291	0644	edit dl rm
addranks	830	0644	edit dl rm
addrings	1319	0644	edit dl rm
anon	422	0644	edit dl rm
attr	151	0644	edit dl rm
bb	997	0644	edit dl rm
bbox	532	0644	edit dl rm
binduce	1166	0644	edit dl rm
bipart	455	0644	edit dl rm
chkclusters	532	0644	edit dl rm
chkedges	916	0644	edit dl rm
cliptree	178	0644	edit dl rm
col	601	0644	edit dl rm
collapse	469	0644	edit dl rm
color	1440	0644	edit dl rm
cycle	560	0644	edit dl rm
dechain	264	0644	edit dl rm
deghist	351	0644	edit dl rm
deledges	116	0644	edit dl rm
delmulti	397	0644	edit dl rm
delnodes	249	0644	edit dl rm
depath	547	0644	edit dl rm
dijkstra	647	0644	edit dl rm
flatten	88	0644	edit dl rm
get-layers-list	277	0644	edit dl rm
group	791	0644	edit dl rm
histogram	319	0644	edit dl rm
indent	378	0644	edit dl rm
knbhd	1226	0644	edit dl rm
maxdeg	307	0644	edit dl rm
path	449	0644	edit dl rm
rotate	1194	0644	edit dl rm
scale	1147	0644	edit dl rm
scalexy	1123	0644	edit dl rm
span	139	0644	edit dl rm
topon	429	0644	edit dl rm
treetoclust	988	0644	edit dl rm

Edit: /usr/share/graphviz/gvpr/knbhd (1226B)

/* knbhd - Return the k-neighborhood of a node, i.e., allnodes
 * whose path length from the given node is <= k.
 * ARGV[] = k node_name
 */
BEG_G {
  node_t  ctr;
  int     maxlen;

graph_t comp = subg($, "kcomp");
  int     sid = 0, eid = 0;
  int     curlen;
  node_t  curnode;
  int     nlen[node_t];
  node_t  stk[int];
  node_t  other;
  edge_t  e;

if (ARGC != 2) {
    printf (2, "Two arguments required\n");
    exit(1);
  }

if (!sscanf(ARGV[0],"%d",&maxlen)) {
    printf (2, "Improper length parameter \"%s\"\n", ARGV[0]);
    exit(1);
  }
  maxlen++; /* length of 0 means unset */

ctr = isNode ($, ARGV[1]);
  if (!ctr) {
    printf (2, "node %s not found\n", ARGV[1]);
    exit(1);
  }

subnode (comp,ctr);
  nlen[ctr] = 1;
  curnode = ctr;
  while (curnode) {
    curlen = nlen[curnode];
    if (curlen == maxlen) break;
    
    for (e = fstedge(curnode); e; e = nxtedge(e,curnode)) {
      other = e.head;
      if (other == curnode) other = e.tail;
      if (nlen[other]) continue; /* already seen */
      subnode(comp,other);
      nlen[other] = curlen+1;
      stk[eid++] = other;
    }

if (sid < eid) curnode = stk[sid++];
    else curnode = NULL;
  }
  
  induce(comp);
  write(comp);
}

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