The performance of the planners can be described by the
planning time required to reach the goal region and also by the
quality of the solutions that are found (e.g. the trajectory length).
Another important aspect of the planners is their reliability, which
is described by their success rate of finding a solution. Stochastic
RRT-based algorithms may fail to reach the goal region defined by
radius dgoal = 1 map unit around the goal configuration, even if
such a solution exists. The success ratio describes the number of
successful trials where the goal is approached by the tree, over
number of all trials.