def _transact(graph: nx.MultiGraph, src: int, tgt: int, amount: int, new_node: int, info: dict):
from more_itertools import pairwise
path, weights, fees = find_route(graph, src, tgt, amount)
# no path found
if path is None:
info['no_path'] += 1
return
for (node, neighbour) in pairwise(path):
channel_trans_amt = weights[neighbour]
channel_policy = graph.get_policy(node, neighbour)
# channel cannot handle transaction
if channel_policy.balance < channel_trans_amt:
info['channel_imbalance'] += 1
if node == new_node or neighbour == new_node:
info['failure'][node, neighbour] += 1
raise Exception('Adversary channel imbalance')
return
# record successful transaction
info['total_success'] += 1
total_amt = 0
# move amount between nodes in path
for (node, neighbour) in pairwise(path):
if neighbour is None:
# remove total amount from src
graph.nodes[path[0]]['data'].capacity -= total_amt
# add amount to tgt
graph.nodes[node]['data'].capacity += weights[node]
break
channel_trans_amt = weights[neighbour]
channel_policy = graph.get_policy(node, neighbour)
# pay channel fees to node
graph.nodes[node]['data'].capacity += fees[node]
total_amt += fees[node]
# shift channel balance
channel_policy.balance -= channel_trans_amt
graph.get_policy(neighbour, node).balance += channel_trans_amt
# record profit for adversary
if node == new_node or neighbour == new_node:
info['success'][node, neighbour] += 1
info['profit'][node, neighbour] += fees[node]
def reward(g: nx.MultiGraph, edge: Tuple[int, int], const_amt: int, fee_type: str, fee: int = None) -> int:
# debugging
# print_flag = fee is not None
u, v = edge
if fee is not None:
g.update_fee(u, v, fee, fee_type)
else:
fee = getattr(g.get_policy(u, v), fee_type)
ebc = edge_betweenness(g, const_amt)[edge]
# debugging
# if print_flag:
# print('({:>3d}, {:>3d}) fee {:>9d} ebc {:>9f} '.format(
# u, v, fee, ebc), end='')
return fee * ebc
