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    <p>Hi Albert,</p>
    <p>In SART, many operations are performed on CPU even if the forward
      and back projections are the CUDA ones. The diagram in the
      SARTConeBeamReconstructionFilter documentation
(<a class="moz-txt-link-freetext" href="http://www.openrtk.org/Doxygen/classrtk_1_1SARTConeBeamReconstructionFilter.html">http://www.openrtk.org/Doxygen/classrtk_1_1SARTConeBeamReconstructionFilter.html</a>)
      shows all the sub-filters SART uses. Among these, some can be
      replaced by CUDA filters (all the sources, and the displaced
      detector), and some currently cannot (Extract, Subtract, Multiply,
      DivideOrZeroOut, Add, and RayBoxIntersection) because we have not
      implemented these operations on GPU yet. <br>
    </p>
    <p>If you are interested in helping do this, let me know, and I'll
      guide you through the code to get you started. Otherwise, you may
      want to try rtkconjugategradient, which is fully implemented in
      CUDA, instead of rtksart. It will require more iterations (try 20
      at first) but is more stable, and may end up taking the same time.
      <br>
    </p>
    <p>Best,</p>
    <p>Cyril<br>
    </p>
    <br>
    <div class="moz-cite-prefix">On 22/05/2018 13:36, Albert M wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAOuvoLHUyYxBLi-JGg9jGeuUd+Bf21bMKwo-rQJETvYb6v_T6A@mail.gmail.com">
      <div dir="ltr">Hi,
        <div><br>
        </div>
        <div>I'm using GPU (NVIDIA TITAN Xp) to reconstruct
          tomosynthesis images by SART method, i've no error and
          apparently results are fine. </div>
        <div><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">In
            addition GPU reconstruction it's 2x faster than SART CPU
            (normal) <span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">reconstruction</span>
            (200sec vs 400sec) </span></div>
        <div><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br>
          </span></div>
        <div>But GPU usage is like 2~3%. Why is so low? How I can
          increase this?<br>
        </div>
        <div><br>
        </div>
        <div>PD: 
          <span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">I'm
            using cuda at SART setting SetBackProjectionFilter and
            SetForwardProjectionFilter at 2.</span>
        </div>
        <div><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br>
          </span></div>
        <div><span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br>
          </span></div>
        <div>Can someone help me? </div>
        <div><br>
        </div>
        <div>Thank you!</div>
      </div>
      <br>
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      <br>
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    </blockquote>
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