[ros-users] slam_gmapping: extracting pose history

[Brian Gerkey]

On Mon, May 17, 2010 at 11:09 AM, René Wagner <rene.wagner at dfki.de> wrote:
> Suppose you have N particles and K scans. Using the old configuration,
> ScanMatcher::registerScan() would be called K times using the more
> expensive m_generateMap==true code path. With the proposed changes
> applied, this is done N times (AFAICT).
>
> K increases over time. As K>N, the old approach will have to do more
> work (and, as K becomes large, it will eventually run out of memory).
> I suspect the basic_stage_localization bag file is too short to cover
> the K>N case. Maybe someone with a larger log file would like to
> test this or share such a log file in bag format?

hi Rene,

I agree with your analysis.

The practical issue with the patch is that, even a moderate value of N
(I've been testing with the default, N=30) entails a constant
computational load exceeding what a single 3GHz core can do.

I think that the constant-time update is the way to go, but that it
will be hard to use without also multi-threading the filter update
step in GMapping.

	brian.