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rqt plot sometimes display different results

asked 2016-01-17 21:36:01 -0500

dmngu9 gravatar image

updated 2016-01-17 22:30:12 -0500

hi, i have a bag file and a ros node. I plot the results from the ros node. I notice sometimes the plot is different even though i did not change the code in the node. Why does this happen?

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answered 2016-01-17 21:42:58 -0500

ahendrix gravatar image

rqt_plot does autoscaling of the data, so the plot may look different from one run to the next if the limits are different, and ROS does not guarantee delivery of every message, so rqt_plot may miss a few messages at startup. This is probably normal.

On the other hand, if sometimes it displays a square wave, and other times it displays a smiley face, there's probably something wrong. It would really help if you described HOW the plots are different, and maybe included screenshots the show how the plots are different.

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just added the 2 graphs. they are slightly different

dmngu9 gravatar image dmngu9  ( 2016-01-17 22:30:39 -0500 )edit

This looks like running your node online and offline produces slightly different results. I don't think the issue is with rqt_plot.

ahendrix gravatar image ahendrix  ( 2016-01-18 02:39:36 -0500 )edit

I think you should ask a new question and describe your algorithm, the environment that it runs in online, and the environment that it runs in offline. Be sure to describe if the rate is configured differently, if the processors are different, and if there are any other tasks using the CPU.

ahendrix gravatar image ahendrix  ( 2016-01-18 02:41:55 -0500 )edit

both plots were produced running algorithm online with data from bag file. I wonder what would be the cause?

dmngu9 gravatar image dmngu9  ( 2016-01-18 19:29:29 -0500 )edit

I still don't understand your setup or your algorithm, and I still think you should ask a new question.

ahendrix gravatar image ahendrix  ( 2016-01-18 20:16:55 -0500 )edit

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Asked: 2016-01-17 21:36:01 -0500

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Last updated: Jan 17 '16