Hi Radu, Hi Tully
thanks for the information.
As I understand it now, it is possible to create the architecture having
just such a nodelet-manager running on all machines. Now, I just need
polymorphism in a rosmsg and its done. :)
Cheers,
Uli
Tully Foote wrote:
> Uli,
>
> You are correct that nodelets are basically a thin layer on top of
> pluginlib. The goal of nodelets is to facilitate composition of
> higher level algorithms maintaining the ROS interface for
> compatability. And with forthcoming roscpp improvements, messages can
> be passed intraprocess with zero copies. And you can have arbitrarily
> many nodelets in a single process.
>
> For your specific questions:
> - Likely you would want to convert each of your plugins into a nodelet.
> - As Radu stated, nodelets don't put any restrictions on what you can
> do inside of them, service calls and servers are definitely fine.
> - For "linking" nodelets directly with a node, all you have to do is
> create a nodelet::NodeletLoader class in the node into which you want
> to load the nodelets. Then you can address the node as a nodelet
> manager, just like a standalone manager.
>
> Tully
>
> PS please see my last email about stability. Keep in mind that
> nodelets are still in the early developmental stage and will be
> changing. http://www.ros.org/wiki/StackVersionPolicy
>
> On Mon, Mar 15, 2010 at 7:41 AM, Radu Bogdan Rusu
> <rusu@willowgarage.com <mailto:rusu@willowgarage.com>> wrote:
>
> Hi Uli,
>
> Think about a nodelet as a C++ class with a ROS interface, sitting
> on top of pluginlib. There aren't a lot of
> constraints right now, so you can do pretty much what you want.
> That being said, the nodelets themselves are just a
> small part of a bigger architectural change that we are pushing,
> that also includes roscpp optimizations, etc.
>
> The nodelet and nodelet_topic_tools are already released under
> common 1.1, so you can already give them a try.
>
> We are working on constructing a set of library layers on top of
> nodelets, including stacks for 3D point cloud
> processing (PCL), 2D image processing (IPL?), and machine learning
> (MLL?). PCL has already been released with
> point_cloud_perception 0.1, while the others are being developed
> right now. These stacks/packages should provide good
> examples on how to use the nodelets architecture for 2D/3D
> processing and learning.
>
> Cheers,
> Radu.
> --
> | Radu Bogdan Rusu | http://rbrusu.com/
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>
>
>
> --
> Tully Foote
> Systems Engineer
> Willow Garage, Inc.
> tfoote@willowgarage.com <mailto:tfoote@willowgarage.com>
> (650) 475-2827
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--
Ulrich Klank klank@in.tum.de
Technische Universität München | Boltzmannstr 3 |
85748 Garching bei München | Germany
www9.in.tum.de/people/klank | Tel: +49 89 289 - 17777
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