2 # This file is part of GNUnet
3 # (C) 2013, 2018 Christian Grothoff (and other contributing authors)
5 # GNUnet is free software: you can redistribute it and/or modify it
6 # under the terms of the GNU Affero General Public License as published
7 # by the Free Software Foundation, either version 3 of the License,
8 # or (at your option) any later version.
10 # GNUnet is distributed in the hope that it will be useful, but
11 # WITHOUT ANY WARRANTY; without even the implied warranty of
12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 # Affero General Public License for more details.
15 # You should have received a copy of the GNU Affero General Public License
16 # along with this program. If not, see <http://www.gnu.org/licenses/>.
18 # SPDX-License-Identifier: AGPL3.0-or-later
20 from __future__ import absolute_import
21 from __future__ import print_function
22 from __future__ import division
23 from builtins import str
24 from builtins import range
25 from past.utils import old_div
28 from math import ceil, log, floor
29 from past.builtins import xrange
33 """ count the bits set in n"""
44 def simulate(k, n, verbose):
46 largest_arc = old_div(int(2**ceil(log(n, 2))), 2)
47 num_ghosts = (2 * largest_arc) - n
49 print("we have", num_ghosts, "ghost peers")
50 # n.b. all peers with idx<k are evil
51 peers = list(range(n))
52 # py2-3 compatible, backwards.
53 # refer to http://python-future.org/compatible_idioms.html#xrange
54 info = [1 << x for x in range(n)]
58 if bsc(info[x]) < n-k:
66 while arc <= largest_arc:
68 print("-- subround --")
69 new_info = [x for x in info]
70 for peer_physical in range(n):
71 peer_logical = peers[peer_physical]
73 partner_logical = (peer_logical + arc) % n
74 partner_physical = peers.index(partner_logical)
75 if peer_physical < k or partner_physical < k:
77 print("bad peer in connection", peer_physical, "--", partner_physical)
79 if peer_logical & arc == 0:
82 print(peer_physical, "connects to", partner_physical)
83 peer_type = "outgoing"
84 if peer_logical < num_ghosts:
85 # we have a ghost, check if the peer who connects
86 # to our ghost is actually outgoing
87 ghost_partner_logical = (peer_logical - arc) % n
88 if ghost_partner_logical & arc == 0:
89 peer_type = peer_type + ", ghost incoming"
90 new_info[peer_physical] = new_info[peer_physical] | info[peer_physical] | info[partner_physical]
91 new_info[partner_physical] = new_info[partner_physical] | info[peer_physical] | info[partner_physical]
93 peer_type = "incoming"
95 print("type of", str(peer_physical) + ":", peer_type)
103 if __name__ == "__main__":
104 parser = argparse.ArgumentParser()
105 parser.add_argument("k", metavar="k", type=int, help="#(bad peers)")
106 parser.add_argument("n", metavar="n", type=int, help="#(all peers)")
107 parser.add_argument("r", metavar="r", type=int, help="#(rounds)")
108 parser.add_argument('--verbose', '-v', action='count')
110 args = parser.parse_args()
112 for n in range(0, args.r):
113 sum += simulate(args.k, args.n, args.verbose)
114 print(old_div(sum, args.r))