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    <p>See</p>
    <p><a class="moz-txt-link-freetext" href="https://gitlab.dune-project.org/extensions/dune-vtk/-/merge_requests/47">https://gitlab.dune-project.org/extensions/dune-vtk/-/merge_requests/47</a></p>
    <p>for an example implementation of an edge-datacollector, or more
      generally a data-collector that collects data from any requested
      codim sub-entity-set.</p>
    <p>Best,<br>
      Simon<br>
    </p>
    <div class="moz-cite-prefix">On 6/22/23 15:41, Simon Praetorius
      wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:d5c3cf48-6011-b195-b7af-4f360df6ab11@tu-dresden.de">
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      <p>Hi Santiago,</p>
      <p>Maybe this is also similar in dune-vtk. There, the "extractor"
        is called "datacollector". You can implement an interface where
        you can essentially collect whatever you want. But there is no
        example for intersection grids.</p>
      <p>In the simplest form you could follow the
        ContinuousDataCollector. If you do not have a parallel grid it
        can even be simplified. The numPoints() function should return
        the number of vertices in the grid and the numCells() function
        the number of edges. The points() implementation is the same as
        in the continuous data-collector and the cells() function just
        iterates over the edges instead of the elements. The only thing
        where you need to be a bit careful is the pointData() (or
        cellData()) function. The input is a grid-function. The
        abstraction is currently not general enough to allow
        grid-functions to be bound to entity sets that are not the
        elements of the grid. Thus, the implementation for the
        pointData() should be the same as a the ContinuousDataCollector
        and for the cellData() you just need to evaluate in e.g. the
        edge centers instead of the element centers.</p>
      <p>I hope you got an idea of how to implement it. As I said, it is
        not yet tested and I cannot give any guarantees that it works.
        But if it does, it would be great if you could contribute this
        to the repository.<br>
      </p>
      <p>Best,<br>
        Simon<br>
      </p>
      <div class="moz-cite-prefix">On 6/22/23 08:05, Christian Engwer
        wrote:<br>
      </div>
      <blockquote type="cite"
        cite="mid:13FB937D-91F8-4966-9B4C-F9362F7880AE@uni-muenster.de">
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        <div dir="auto">Dear Santiago,<br>
          <br>
          long ago I implemented something like that to visualise data
          of a UDG discretization. I'm partially using the dune-grid vtk
          writer, but defined a different "extractor" to collect the
          data.<br>
          <br>
          We never polished it, if you want, I can give you access.<br>
          <br>
          Best Christian <br>
        </div>
        <br>
        <br>
        <div class="gmail_quote">
          <div dir="auto">Am 22. Juni 2023 06:40:14 MESZ schrieb "Ospina
            De Los Rios, Santiago" <a class="moz-txt-link-rfc2396E"
              href="mailto:santiago.ospina@iwr.uni-heidelberg.de"
              moz-do-not-send="true"><santiago.ospina@iwr.uni-heidelberg.de></a>:</div>
          <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
            0.8ex; border-left: 1px solid rgb(204, 204, 204);
            padding-left: 1ex;"> Dear Dune Developers,<br>
            <br>
            I was wondering if any of you had faced the problem of
            writing data for intersection data for VTK? In particular, I
            am interested in 0D/1D/2D VTK meshes+data (not C++ grids)
            resulting from the intersection between the 1D/2D/3D
            non-overlapping domains of a grid. So far, I only use
            conforming grids, so either interesection or codim:=1 entity
            writers would do for me.<br>
            <br>
            I could not see any hint to these kind of writers in the
            dune-grid and dune-vtk modules. Maybe I missed it? So I was
            wondering if any of you already had similar problem/solution
            or if you see an easy way to re-use the existing writers for
            this purpose? Any pointer would be appreciated, thanks!<br>
            <br>
            Best,<br>
            Santiago </blockquote>
        </div>
        <br>
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        <pre class="moz-quote-pre" wrap="">_______________________________________________
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      </blockquote>
      <pre class="moz-signature" cols="72">-- 
Dr. Simon Praetorius
Institut für Wissenschaftliches Rechnen
Fakultät Mathematik
Technische Universität Dresden
Tel.: TUD-34432
Mail: <a class="moz-txt-link-abbreviated moz-txt-link-freetext" href="mailto:simon.praetorius@tu-dresden.de" moz-do-not-send="true">simon.praetorius@tu-dresden.de</a>
Web: <a class="moz-txt-link-freetext" href="https://tu-dresden.de/Members/simon.praetorius" moz-do-not-send="true">https://tu-dresden.de/Members/simon.praetorius</a></pre>
      <br>
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      <pre class="moz-quote-pre" wrap="">_______________________________________________
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</pre>
    </blockquote>
    <pre class="moz-signature" cols="72">-- 
Dr. Simon Praetorius
Institut für Wissenschaftliches Rechnen
Fakultät Mathematik
Technische Universität Dresden
Tel.: TUD-34432
Mail: <a class="moz-txt-link-abbreviated" href="mailto:simon.praetorius@tu-dresden.de">simon.praetorius@tu-dresden.de</a>
Web: <a class="moz-txt-link-freetext" href="https://tu-dresden.de/Members/simon.praetorius">https://tu-dresden.de/Members/simon.praetorius</a></pre>
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