#5 FloatFFT_2D.realForward(float[][]) hangs for size >= 8K

open
nobody
None
5
2012-02-16
2012-02-16
No

This is related to FFT 1D concurrency thresholds whereas all threads are already busy within FloatFFT_2D.realForward().

As a workaround, I explicitly set these thresholds to INFINITY to disable FFT 1D parallelism:
// JTransforms: disable FFT_1D parallelism:
ConcurrencyUtils.setThreadsBeginN_1D_FFT_2Threads(Integer.MAX_VALUE);
ConcurrencyUtils.setThreadsBeginN_1D_FFT_4Threads(Integer.MAX_VALUE);

Maybe JTransforms could automatically disable FFT 1D parallelism when FFT 2D are computed ...

I propose that the FloatFFT_2D constructor which instanciate FloatFFT_1D objects (row/columns) define a flag useThreads = false in order to disable concurrency in such cases ...

Discussion

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    Anonymous - 2012-08-08

    Another workaround seems to work for me...

    ConcurrencyUtils.setThreadsBeginN_2D(Integer.MAX_VALUE);

    the recommended ones had no effects in my case (images sizing some MB!!)

     
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    Anonymous - 2012-08-08

    Just add this method to edu.emory.mathcs.utils.Concurrencyutils:

    public static void shutdown() {

    THREAD_POOL.shutdown();
    }

    and invoke it whenever you want.
    This will shutdown all the threads in the thread pool!

     
    Last edit: Anonymous 2015-11-20
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