[Insight-developers] interrupting filter execution

[Paul Koshevoy]

Miller, James V (GE, Research) wrote:
> Paul,
>
> So what does your final version of the ReportProgress() look like?
>
>   
I use ITK 2.4.1, but ProgressAccumulator hasn't changed in 2.8.1, so
here is my patched version:

void
ProgressAccumulator
::ReportProgress(Object *, const EventObject &event)
{
  if (m_MiniPipelineFilter->GetAbortGenerateData())
  {
    m_MiniPipelineFilter->AbortGenerateDataOff();
   
    ProcessAborted e(__FILE__, __LINE__);
    e.SetDescription("ProgressAccumulator detected AbortGenerateData flag");
    throw e;
  }
 
  ProgressEvent  pe;
  IterationEvent ie;
  if( typeid( event ) == typeid( pe ) )
    {
    // Add up the progress from different filters
    m_AccumulatedProgress = m_BaseAccumulatedProgress;

    FilterRecordVector::iterator it;
    for(it = m_FilterRecord.begin();it!=m_FilterRecord.end();++it)
      {
      m_AccumulatedProgress += it->Filter->GetProgress() * it->Weight;
      }

    // Update the progress of the client mini-pipeline filter
    m_MiniPipelineFilter->UpdateProgress(m_AccumulatedProgress);
    }
  else if (typeid( event ) == typeid ( ie ) )
    {
    }
}


> Did you essentially just move the check for GetAbortGenerateData() to the
> beginning of the method?  
>
>   
I added it there, as suggested by Karthik Krishnan.

> Also, it is only the DiscreteGaussian filter where you could not properly
> catch the exceptions? 
DiscreteGaussian is the one I hit most often, because it was relatively
slow compared to other filters, it gave me plenty of time to hit the
stop button. I am not sure why I was not able to catch any of the
multiply-thrown exceptions, but I can catch the exception when it's
thrown only once. I can now report that I have been able to successfully
abort the CastImage  and  ShrinkImage filter. I still can't abort
ImageFileReader -- I don't think it uses a ProgressAccumulator internally.

>  The DiscreteGaussian filter uses a StreamingImageFilter
> internally.  Perhaps that filter is not handling the exceptions properly
> (it is a bit of an odd duck).
>
> If you could try another filter, say something like the MedianImageFilter
> and see of you have the same issues with the original ProgressAccumulator
> code?
>
>   
I'll try.
> The DiscreteGaussian filter also uses a series of NeighborhoodOperatorImageFilters
> which in turn use an itk::ProgressReporter.  The ProgressReporter is set up 
> such that only one thread modifies the progress of a filter (without using mutexes).
> However, all threads check the AbortGenerateData flag and throw a ProcessAborted.
> This is necessary because if only the first thread threw the exception, then the other
> threads for the filter would keep running.  If your app then tried to run the filter
> again immediately, you could have multiple threads trying to modify the same data.
> The Multithreader should catch the exceptions for N-1 of the threads, with only one
> thread rethrowing the ProcessAborted to the calling context.
>
> We may need to build a small executable that mimics what you are doing.  Forces an
> Abort and makes sure the filter shuts down properly.
>
> Ultimately, we'll need to patch ITK.
>
> Jim
>
>