Triggers a function set_matcher which automatically raises an exception; probably needs to be implemented somewhere.

db.users.group({
reduce: function(obj, prev) {
prev.sums =

{ y_levels: prev.sums.y_levels + obj.current_y_level, x_levels: prev.sums.x_levels + obj.current_x_level, count: prev.sums.count + 1 }

},
cond: {current_position: { $near: [56.553823, 8.565619],
$maxDistance: 10}},
initial: { sums:

{ y_levels: 0, x_levels: 0, count: 0 }

}
});

produces :

uncaught exception: group command failed: {
"errmsg" : "exception: manual matcher config not allowed",
"code" : 13285,
"ok" : 0