Doug’s MATLAB Video Tutorials

May 8th, 2009

Implementing a simple circular buffer

 Internet explorer users: Please follow the permalink at the bottom of this post to see the correct video… We are working on this! Sorry! I frequent StackOverflow.com answering MATLAB question. Here is the answer to one that recently went by. In this three minute video I show how to implement a circular buffer for keeping a limited time history. This is useful for keeping only the history that you need for a variable. A strip chart could be plotted from one of these.

By Doug Hull

18:16 UTC | Posted in Format: Video, Level: Basic | Permalink |

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3 Responses to “Implementing a simple circular buffer”

  1. Petter replied on May 9th, 2009 at 14:22 UTC :

    Wouldn’t that solution force the entire array to be reshuffled every time a new value is added?

  2. Daniel Armyr replied on May 11th, 2009 at 07:23 UTC :

    Like Petter, I wonder if this should be considdered an efficient implementation or only an easy one?

    I use a few rinbuffers here and there and they are all implemented like this, because it is easy. However, the line buffer = [newValue buffer(1:end-1)] gives the optimizer in me the shivers. Is that just me?

  3. dhull replied on May 11th, 2009 at 13:37 UTC :

    I profiled this with a really large amount of data, more iterations and longer buffer. That part of the video is on the “cutting room floor”. Basically, there is a negligible performance hit. To be a real test, it would need to be done in context to see if this architecture is a problem.

    This video is in keeping with one of the central themes of my programming style: “Avoid premature optimization”. If I were to try and avoid the churn that this circular buffer goes through, the complexity and readability would suffer.

    -Doug

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