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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">Dear Petsc users,
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<div>I have a DM object by claiming </div>
<div><span style="font-family: Menlo; font-size: 11px;">DMDACreate3d(PETSC_COMM_WORLD,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_STENCIL_BOX,</span><span style="font-family: Menlo; font-size: 11px; color: rgb(39, 42, 216);">32</span><span style="font-family: Menlo; font-size: 11px;">,</span><span style="font-family: Menlo; font-size: 11px; color: rgb(39, 42, 216);">32</span><span style="font-family: Menlo; font-size: 11px;">,</span><span style="font-family: Menlo; font-size: 11px; color: rgb(39, 42, 216);">32</span><span style="font-family: Menlo; font-size: 11px;">,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,</span><span style="font-family: Menlo; font-size: 11px; color: rgb(39, 42, 216);">3</span><span style="font-family: Menlo; font-size: 11px;">,</span><span style="font-family: Menlo; font-size: 11px; color: rgb(39, 42, 216);">5</span><span style="font-family: Menlo; font-size: 11px;">,</span><span style="font-family: Menlo; font-size: 11px; color: rgb(39, 42, 216);">0</span><span style="font-family: Menlo; font-size: 11px;">,</span><span style="font-family: Menlo; font-size: 11px; color: rgb(39, 42, 216);">0</span><span style="font-family: Menlo; font-size: 11px;">,</span><span style="font-family: Menlo; font-size: 11px; color: rgb(39, 42, 216);">0</span><span style="font-family: Menlo; font-size: 11px;">,&da);</span></div>
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<div>There is a problem with it, because it uses <span style="font-family: Menlo; font-size: 11px;">DMDA_STENCIL_BOX, </span><span style="font-size: 10pt;">and the stencil width is 5, quite big. </span></div>
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<div><font size="2">However, in fact, I don't need such big stencils everywhere, I only need it at a sparse number of locations. I'm wondering how to allocate memory only in those sparse </font>number<font size="2"> of locations? </font></div>
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<div><font size="2">Thank you very much! </font></div>
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<div><font size="2">Best,</font></div>
<div><font size="2">Hui</font></div>
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