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I am trying to parallellize a certain algorithm on point cloud processing for which I decided to take advantage of ROS nodelets' zero copy transport. So I will have one nodelet publishing them and the other subscribing, However, my issue is that the nodelets never run parallelly - either by using a launch file or by using the nodelet::loader class. Thanks in advance, I have been really tearing my hair out on this one.
The documentation (wiki/nodelet) says this:
A nodelet manager has a pool of threads which is shared across all nodelets run within the manager. This is set by the parameter "num_worker_threads".
There are two possible threading APIs to use in code running in nodelets. The default threading model has a single thread for all callbacks. There is a multithreaded API as well.
[..]
1.6.3 Multi Threaded API
Using the methods
getMTNodeHandle()andgetMTPrivateNodeHandle()callbacks will be distributed over the thread pool of the manager.
Are you using those?
There are some gotchas though, see ros/nodelet_core#77 and ros/nodelet_core#25 fi (and the linked lucasw/nodelet_demo@c43e08bf).
Thanks @gvdhoorn, but I've tried setting the parameter num_worker_threads and using getMTNodeHandle. I think the real issue here is that the onInit() function is first called when loading the nodelet and the publisher subscriber code is in there. Maybe I am a nodelet noob, but is this how it's done?
Yes. I am using 'getMTNodeHandle()'. The issue here is that my publisher is in one nodelet and my subscriber is in another nodelet. So what happens is I load my first nodelet and I publish in its onInit() function. Then, my subscriber nodelet is loaded and runs its Init() function and gets nothing.
I have seen pretty much one example online like so http://www.clearpathrobotics.com/asse... where the publisher and subscriber are both in one nodelet. @gvdhoorn, can you have seperate nodelets subscribing & publishing? Am I misunderstanding nodelets ? Thanks alot
I publish in its onInit() function.
I'm not sure you're supposed to do that.
onInit() should initialise your nodelet (ie: allocate resources, open files, create pubs/subs, etc). It's not meant to do any 'real work'.
Can you show some code that illustrates what you're doing?
re: example: there are multiple projects using nodelets. One I already linked: lucasw/nodelet_demo.
Asked: 2018-11-08 05:11:36 -0500
Seen: 823 times
Last updated: Nov 08 '18
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I'm not sure how this is a duplicate question. Can you clarify?