In a specific map scene, the cbs algorithm cannot find a solution and falls into an infinite loop

[lvyv]

I once made a map as attachment,
'#' means obstacle,
'.' means space,
'1','2','3' is start position of three agent, and 'A', 'B', 'C' is the goal position one by one.

When I apply the cbs implemention, It falls into an infinite loop.
To reproduce the problem, I slightly modifed the source code of cbs.cpp as following.
......
// std::unordered_set obstacles;
// for (const auto& node : config["map"]["obstacles"]) {
//obstacles.insert(Location(node[0].as(), node[1].as()));
// }
std::unordered_set obstacles;
std::ifstream map(mapFile);

int y = 0;
while (map.good()) {
std::string line;
std::getline(map, line);
int x = 0;
for (char c : line) {
if (c == '#') {
obstacles.insert(Location(x, y));
}
++x;
}
++y;
}
......

map.txt

[whoenig]

• CBS does not guarantee to terminate with an error if no solution exists. (From your map, it looks like a solution should exist, though)
• You can try with bounded suboptimal variants, such as ECBS, since CBS can be very slow on larger examples.