Figures below show the difference between desired epicentral distance and the actual distance resulting of take off angle optimization. This optimization stops when the shooting error is smaller than 0.001°. In very rare cases, a solution of this quality is not found (although the shooting error is still smaller than 0.01°), but usually, the shooting error is much smaller than this limit and can therefore be neglected. (The shooting error is controlled by an epsilon parameter which is set to 0.001°. Reducing this parameter to 0.00001° does not reduce the travel time error but increases the cpu time needed.)
The Shooting error is independent of wave type and model discretization.