[Rtk-users] rtkfdk: CudaFDKWeightProjectionFilter runs twice

[Simon Rit]

Hi Chao,
It looks bad but I couldn't reproduce the problem. What I did is add
messages in the GPUGenerateData and launch a very simple sequence of
command lines:
  rtksimulatedgeometry -n 8 -o g
  rtkprojectshepploganphantom -g g -o proj.mha
  rtkfdk -p . -r proj.mha -o fdk.mha -g g --hardware cuda
in which case I go only once in each GPUGenerateData. Can you give us
a command line example where you can see the problem?
Thanks,
Simon

On Mon, Jun 1, 2015 at 6:53 PM, Chao Wu <wuchao04 at gmail.com> wrote:
> Hi all,
>
> When testing CUDA-based FDK I found the CudaFDKWeightProjectionFilter seems
> to rerun unnecessarily. Details below:
>
> In FDKConeBeamReconstructionFilter<TInputImage, TOutputImage,
> TFFTPrecision>::GenerateData() the three sub-filters run separately for
> timing:
>
>     m_PreFilterProbe.Start();
>     m_WeightFilter->Update();
>     m_PreFilterProbe.Stop();
>
>     m_FilterProbe.Start();
>   m_RampFilter->Update();
> m_FilterProbe.Stop();
>
>     m_BackProjectionProbe.Start();
>     m_BackProjectionFilter->Update();
>     m_BackProjectionProbe.Stop();
>
> However with some debug procedure I found when executing
> m_RampFilter->Update() the m_WeightFilter is updated again. Maybe there's
> something wrong with filter modified time or flags of CPU/GPU buffer?
>
> Furthermore, if I remove m_WeightFilter->Update() then both m_WeightFilter
> and m_RampFilter will rerun during update of m_BackProjectionFilter. Only if
> I remove both m_WeightFilter->Update() and m_RampFilter->Update() and let
> m_BackProjectionFilter execute the whole minipipeline, all filters will run
> nicely only once for each projection subset.
>
> The results are identical for all cases I tested.
>
> I did not check whether the same issue applies to the CPU or OpenCL version.
>
> Regards,
> Chao
>
> _______________________________________________
> Rtk-users mailing list
> Rtk-users at public.kitware.com
> http://public.kitware.com/mailman/listinfo/rtk-users
>