Re: [ompl-users] Distance metric and interpolation for RRTs

[Mark M. <mm...@ri...>]

Hi Anand,

You could derive a new class from DubinsStateSpace where you override distance. This might lead to some surprising results. The paths will probably have many twists and turns that path simplification cannot eliminate.

As far as I know there really isn’t an efficient way to search nearest neighbors in non-metric spaces.

Best,

Mark



> On Jun 28, 2017, at 5:54 PM, Anand <ana...@gm...> wrote:
> 
> In OMPL, the distance metric used (distance()) and the way in which states are connected (interpolate()) are encapsulated as part of the state space.
> 
> For example, the DubinsStateSpace uses the path length of the Dubins curve to compute the distance() and interpolate().
> 
> Does it make sense for an RRT to use a different distance metric for nearest neighbor computations, than what is used for interpolation?
> 
> In my scenario (planning for a car-like robot), I wonder if it makes sense to speed up nearest neighbor searches by using a distance metric other than Dubins (say Euclidean distance) to find nearest neighbors, but still use Dubins to connect states? This will allow me to use nearest neighbor data structures like GNAT, which I can't otherwise do if I use the Dubins distance metric.
> 
> If not, are there any alternative data structures I can use to speed up nearest neighbor searches for a Dubins-like non-metric space?
> 
> Thanks,
> Anand