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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Hello,</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">I am working in a reader base on vtkMultiBlockDataSet working in parallel Paraview , and I have a question about the vtk internals.</span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">I have a 100s of blocks, and each block has X.Y.Z cells in structured grids with data being cell centered. Each block is a unit , all cells within this block
have the same properties and follow the same physics , but cells in different blocks can have different properties (important for the solver not for visualization)</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">I read and put each block as an element of vtkMultiblockDataSet. Blocks are distributed amongs processor (MPI-Ranks)</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">In Parallel I have been using two approach to distribute the blocks among processors</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""><span style="">1)<span style="font:7.0pt "Times New Roman"">
</span></span></span><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Each Processor takes blocks at random , important is that each processor has the same number of cells</span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Example: block 1 has 100cells, block2- 500, block 3- 300 , block 4-100, block 5 -400</span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Then processor 0 has blocks 1, 2 and 4 = (100+500+100)= 700 cells
</span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Processor 1 has blocks 3 and 5 = (300+400)=700 cells</span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""><span style="">2)<span style="font:7.0pt "Times New Roman"">
</span></span></span><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> I use a Hilbert Curve (HSFC) to take in acount blocks’ position
</span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">i.e., all processor should have the same number of cells, but blocks which are close or next to each other are also in the same processor.</span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">then processor 0 has blocks 1, 2 = (100+500)= 600 cells
</span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Processor 1 has blocks 3,4 and 5 = (300+100+400)=800 cells , because this blocks are connected together.</span></p>
<p class="MsoListParagraph"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Since a have a lot of blocks the imbalance is not such a problem. My problem here is first I have to find out block position (center). I.e., first read
my geometric data, distribute blocks, each processor rereads the data again and corresponding fields.
</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">With that information, can anyone tell me if paraview generates gosht cells? and if yes for wich calculations ? the gosht cells could be be only located at
the boundaries of blocks (elements of vtkMultiBlockDataSet ) </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">What happens when I do a cut, stream tracer, etc. through several blocks, that are not necessarely in the same processor ?</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">And what about parallel remote rendering ? Data scatter like in 1) would perform badly compared with distribution 2)
</span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Thanks in Advance
</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif""> </span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt; font-family:"Arial","sans-serif"">Orlando Rivera </span></p>
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<span style="font-size:8.0pt; font-family:"Arial"; color:silver"><strong>MTU Aero Engines AG</strong></span><br>
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