<div dir="ltr"><div>No it doesn't, it's voxel based. The adjoint which uses the step size is <a href="http://www.openrtk.org/Doxygen/classrtk_1_1CudaRayCastBackProjectionImageFilter.html">CudaRayCastBackProjectionImageFilter</a> but it's very slow and we never use it in practice because it's not practical. When we want to use adjoint operators, we mainly use the CPU version, with double precision when adjointness is very important.<br></div>Simon<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Dec 22, 2017 at 11:31 PM, Yannick Boursier <span dir="ltr"><<a href="mailto:boursier@cppm.in2p3.fr" target="_blank">boursier@cppm.in2p3.fr</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Hi Simon, <br>
</p>
<p>Thank you a lot for your answer, I will try to put the step size
to the voxel size then (if I understand well). It seems that the
implementation of the CudaBackProjectionImageFilter doesn't use
any stepsize. I'll let you know.<br>
</p>
<p>Merry Christmas to you, <br>
Yannick<br>
</p><div><div class="h5">
<br>
<div class="m_-2667162766585569410moz-cite-prefix">Le 22/12/2017 à 22:55, Simon Rit a
écrit :<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>
<div>
<div>Hi Yannick,<br>
</div>
I would just try to change the <a href="http://www.openrtk.org/Doxygen/classrtk_1_1CudaForwardProjectionImageFilter.html#a93671bae5219bada43b9a00b6046dbed" target="_blank">step size</a>. Indeed, the CPU
version is the Joseph projector and it adapts automatically
the step size to each ray for bilinear interpolation in each
slice. The GPU version is a fixed step size combined with a
trilinear interpolation.<br>
</div>
<div>Merry Christmas to you,<br>
</div>
</div>
Simon<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Dec 22, 2017 at 9:17 PM,
Yannick Boursier <span dir="ltr"><<a href="mailto:boursier@cppm.in2p3.fr" target="_blank">boursier@cppm.in2p3.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Hi Cyril, <br>
</p>
<p>Sorry for my late answer. First thank you because your
last trick (removing <InpuImageType>) worked, I
correctly compiled and installed everything.</p>
<p>I am late because I thought that I did something wrong
since when I tested the code by simply projecting then
backprojecting a simple volume, the results between the
CPU-codes and GPU-codes were different and the GPU
result cas clearly wrong. <br>
</p>
<p>I understood this morning the problem and put it in
evidence : the CudaForwardProjectionImageFilt<wbr>er
seems to be not adapted to the case when the size of
voxels and pixels are not equal to 1 whereas the
CudaBackProjectionImageFilter is OK for that !! <br>
</p>
<p>I will try to debug it and let you know.</p>
<p>I wish to all of you a Merry Christmas and relaxing
holidays.</p>
<p>Best ,</p>
<p>Yannick<br>
</p>
<div>
<div class="m_-2667162766585569410h5"> <br>
<div class="m_-2667162766585569410m_-4428931898617340006moz-cite-prefix">Le
18/12/2017 à 16:52, Cyril Mory a écrit :<br>
</div>
<blockquote type="cite">
<p>Hi again Yannick,</p>
<p>Simply removing the <InputImageType> on
line 9 of your .json file made it compile. I
didn't test it yet. Let us know if that works for
you.</p>
<p>Cyril<br>
</p>
<br>
<div class="m_-2667162766585569410m_-4428931898617340006moz-cite-prefix">On
18/12/2017 16:31, Cyril Mory wrote:<br>
</div>
<blockquote type="cite">
<p>Hi Yannick,</p>
<p>You seem to be in a hurry, so I'll start with
an incomplete answer: the
CudaForwardProjectionImageFilt<wbr>er is
templated over its input and output image type,
but the CudaBackProjectionImageFilter isn't
(compare rtkCudaForwardProjectionImageF<wbr>ilter.h
and rtkCudaBackProjectionImageFilt<wbr>er.h,
there is not "template <>" before the
class definition in ...Back..., while it is
there in ...Forward...).<br>
</p>
I'm trying to modify your .json file accordingly,
recompile and test, but I never use SimpleRTK
myself, so you might find the solution before I
do. If so, please report back on this mailing
list.<br>
<br>
Cyril<br>
<br>
<br>
<div class="m_-2667162766585569410m_-4428931898617340006moz-cite-prefix">On
18/12/2017 16:07, Yannick BOURSIER wrote:<br>
</div>
<blockquote type="cite">
<pre>Hello all,
I really need in "relative" emergency to execute the kernel CudaBackProjectionImageFilter using the Python Wrapper provided by SimpleRTK.
Unfortunately, this is not implemented in cuda (CudaForwardProjectionImageFil<wbr>ter is but not the BackProjection).
I tried to define a json file (in attachement) on the base of CudaForwardProjectionImageFilt<wbr>er (since all the h, hxx, cxx, files I looked at seemed to be the same for these two kernels) but it does not compile (cmake instruction OK but not the make instruction) with the following error :
/data/boursier/Compile/rtk-bin<wbr>-extended/SimpleRTK-build/Code<wbr>/BasicFilters/src/srtkCudaBack<wbr>ProjectionImageFilter.cxx: In member function ‘rtk::simple::Image rtk::simple::CudaBackProjectio<wbr>nImageFilter::ExecuteInternal(<wbr>const rtk::simple::Image&, const rtk::simple::Image&)’:
/data/boursier/Compile/rtk-bin<wbr>-extended/SimpleRTK-build/Code<wbr>/BasicFilters/src/srtkCudaBack<wbr>ProjectionImageFilter.cxx:132:<wbr>16: error: ‘rtk::CudaBackProjectionImageF<wbr>ilter’ is not a template
typedef rtk::CudaBackProjectionImageFi<wbr>lter<InputImageType> FilterType;
I would very much appreciate some help please because at this point, I have no idea about the problem...
Thanks in advance,
Best regards,
Yannick Boursier</pre>
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