<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  </head>
  <body text="#000000" bgcolor="#FFFFFF">
    <p>Hi Matt,<br>
    </p>
    <p>Just to let you know that after updating to PETSc 3.8.3 version,
      the DMPlexCreateSection in my code now works.</p>
    <p>One more question, what is the PETSC_NULL_XXX for IS pointer, as
      shown below, in C code, it just pass NULL, but in fortran, what is
      the name of null object for pBcCompIS and pBcPointIS. <br>
    </p>
            call
    DMPlexCreateSection(dmda_flow%da,dmda_flow%dim,           &<br>
                                    
    numFields,pNumComp,pNumDof,           &<br>
                                    
    numBC,pBcField,                       &<br>
                                    
    pBcCompIS,pBcPointIS,                 &<br>
                                     PETSC_NULL_IS,section,ierr)<br>
            CHKERRQ(ierr)<br>
    <br>
    Thanks,<br>
    <br>
    Danyang<br>
    <br>
    <div class="moz-cite-prefix">On 18-02-21 09:22 AM, Danyang Su wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:25e20ee5-23ee-a3fc-7b45-f981563f03b4@gmail.com">
      <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
      <p>Hi Matt,</p>
      <p>To test the Segmentation Violation problem in my code, I
        modified the example ex1f90.F to reproduce the problem I have in
        my own code. <br>
      </p>
      <p>If use DMPlexCreateBoxMesh to generate the mesh, the code works
        fine. However, if I use DMPlexCreateGmshFromFile, using the same
        mesh exported from "DMPlexCreateBoxMesh", it gives Segmentation
        Violation error.</p>
      <p>Did I miss something in the input mesh file? My first guess is
        the label "marker" used in the code, but I couldn't find any
        place to set this label.</p>
      <p>Would you please let me know how to solve this problem. My code
        is done in a similar way as ex1f90, it reads mesh from external
        file or creates from cell list, distributes the mesh (these
        already work), and then creates sections and sets ndof to the
        nodes.</p>
      <p>Thanks,</p>
      <p>Danyang<br>
      </p>
      <br>
      <div class="moz-cite-prefix">On 18-02-20 10:07 AM, Danyang Su
        wrote:<br>
      </div>
      <blockquote type="cite"
        cite="mid:f7ad951f-4c94-b549-80d0-508f0cc9315d@gmail.com">
        <meta http-equiv="Content-Type" content="text/html;
          charset=utf-8">
        On 18-02-20 09:52 AM, Matthew Knepley wrote:<br>
        <blockquote type="cite"
cite="mid:CAMYG4GknBNzGcKs-SuUwp_CEVPXB7n65DZbOrLWFjjA9iMTx9g@mail.gmail.com">
          <div dir="ltr">
            <div class="gmail_extra">
              <div class="gmail_quote">On Tue, Feb 20, 2018 at 12:30 PM,
                Danyang Su <span dir="ltr"><<a
                    href="mailto:danyang.su@gmail.com" target="_blank"
                    moz-do-not-send="true">danyang.su@gmail.com</a>></span>
                wrote:<br>
                <blockquote class="gmail_quote" style="margin:0px 0px
                  0px 0.8ex;border-left:1px solid
                  rgb(204,204,204);padding-left:1ex">
                  <div bgcolor="#FFFFFF">
                    <p>Hi All,</p>
                    <p>I tried to compile the DMPlexCreateSection code
                      but got error information as shown below.<br>
                    </p>
                    <p>Error: Symbol 'petsc_null_is' at (1) has no
                      IMPLICIT type</p>
                    <p>I tried to use PETSC_NULL_OBJECT instead of
                      PETSC_NULL_IS, then the code can be compiled but
                      run into Segmentation Violation error in
                      DMPlexCreateSection.<br>
                    </p>
                  </div>
                </blockquote>
                <div>From the webpage</div>
                <div><br>
                </div>
                <div>  <a
href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMPLEX/DMPlexCreateSection.html"
                    moz-do-not-send="true">http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMPLEX/DMPlexCreateSection.html</a> <br>
                </div>
                <div><br>
                </div>
                <div>The F90 version is DMPlexCreateSectionF90. Doing
                  this with F77 arrays would have been too painful.</div>
              </div>
            </div>
          </div>
        </blockquote>
        Hi Matt,<br>
        <br>
        Sorry, I still cannot compile the code if use
        DMPlexCreateSectionF90 instead of DMPlexCreateSection. Would you
        please tell me in more details? <br>
        <br>
        undefined reference to `dmplexcreatesectionf90_'<br>
        <br>
        then I #include <petsc/finclude/petscdmplex.h90>, but this
        throws more error during compilation.<br>
        <br>
        <br>
            Included at
/home/dsu/Soft/PETSc/petsc-3.7.5/include/petsc/finclude/petscdmplex.h90:6:<br>
            Included at ../../solver/solver_ddmethod.F90:62:<br>
        <br>
                  PETSCSECTION_HIDE section<br>
                  1<br>
        Error: Unclassifiable statement at (1)<br>
/home/dsu/Soft/PETSc/petsc-3.7.5/include/petsc/finclude/ftn-custom/petscdmplex.h90:167.10:<br>
            Included at
/home/dsu/Soft/PETSc/petsc-3.7.5/include/petsc/finclude/petscdmplex.h90:6:<br>
            Included at ../../solver/solver_ddmethod.F90:62:<br>
        <br>
                  PETSCSECTION_HIDE section<br>
                  1<br>
        Error: Unclassifiable statement at (1)<br>
/home/dsu/Soft/PETSc/petsc-3.7.5/include/petsc/finclude/ftn-custom/petscdmplex.h90:179.10:<br>
            Included at
/home/dsu/Soft/PETSc/petsc-3.7.5/include/petsc/finclude/petscdmplex.h90:6:<br>
            Included at ../../solver/solver_ddmethod.F90:62:<br>
        <br>
        <blockquote type="cite"
cite="mid:CAMYG4GknBNzGcKs-SuUwp_CEVPXB7n65DZbOrLWFjjA9iMTx9g@mail.gmail.com">
          <div dir="ltr">
            <div class="gmail_extra">
              <div class="gmail_quote">
                <div><br>
                </div>
                <div>  Thanks,</div>
                <div><br>
                </div>
                <div>     Matt</div>
                <blockquote class="gmail_quote" style="margin:0px 0px
                  0px 0.8ex;border-left:1px solid
                  rgb(204,204,204);padding-left:1ex">
                  <div bgcolor="#FFFFFF">
                    <p> </p>
                    <p>dmda_flow%da is distributed dm object that works
                      fine. </p>
                    <p>The fortran example I follow is <a
                        class="gmail-m_8962138310016109093moz-txt-link-freetext"
href="http://www.mcs.anl.gov/petsc/petsc-dev/src/dm/impls/plex/examples/tutorials/ex1f90.F90"
                        target="_blank" moz-do-not-send="true">http://www.mcs.anl.gov/petsc/<wbr>petsc-dev/src/dm/impls/plex/<wbr>examples/tutorials/ex1f90.F90</a>.
                      <br>
                    </p>
                    <p>What parameters should I use if passing null to
                      bcField, bcComps, bcPoints and perm.<br>
                    </p>
                    <pre style="color:rgb(0,0,0);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;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial"><a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/Vec/PetscErrorCode.html#PetscErrorCode" target="_blank" moz-do-not-send="true">PetscErrorCode</a> <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/DMPLEX/DMPlexCreateSection.html#DMPlexCreateSection" target="_blank" moz-do-not-send="true">DMPlexCreateSection</a>(<a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/DM/DM.html#DM" target="_blank" moz-do-not-send="true">DM</a> dm, <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/Vec/PetscInt.html#PetscInt" target="_blank" moz-do-not-send="true">PetscInt</a> dim, <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/Vec/PetscInt.html#PetscInt" target="_blank" moz-do-not-send="true">PetscInt</a> numFields,const <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/Vec/PetscInt.html#PetscInt" target="_blank" moz-do-not-send="true">PetscInt</a> numComp[],const <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/Vec/PetscInt.html#PetscInt" target="_blank" moz-do-not-send="true">PetscInt</a> numDof[], <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/Vec/PetscInt.html#PetscInt" target="_blank" moz-do-not-send="true">PetscInt</a> numBC,const <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/Vec/PetscInt.html#PetscInt" target="_blank" moz-do-not-send="true">PetscInt</a> bcField[], 
const <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/IS/IS.html#IS" target="_blank" moz-do-not-send="true">IS</a> bcComps[], const <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/IS/IS.html#IS" target="_blank" moz-do-not-send="true">IS</a> bcPoints[], <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/IS/IS.html#IS" target="_blank" moz-do-not-send="true">IS</a> perm, <a href="https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/IS/PetscSection.html#PetscSection" target="_blank" moz-do-not-send="true">PetscSection</a> *section)

</pre>
                    <p>#include <petsc/finclude/petscis.h><br>
                      #include <petsc/finclude/petscis.h90><br>
                      #include <petsc/finclude/petscdmplex.h></p>
                    <p>...<br>
                    </p>
                    <p>#ifdef USG<br>
                              numFields = 1<br>
                              numComp(1) = 1<br>
                              pNumComp => numComp<br>
                      <br>
                              do i = 1, numFields*(dmda_flow%dim+1)<br>
                                numDof(i) = 0<br>
                              end do<br>
                              numDof(0*(dmda_flow%dim+1)+1) =
                      dmda_flow%dof<br>
                              pNumDof => numDof<br>
                      <br>
                              numBC = 0<br>
                      <br>
                              call DMPlexCreateSection(dmda_flow%<wbr>da,dmda_flow%dim,         
                      &<br>
                                                    <wbr>  
                      numFields,pNumComp,pNumDof,   <wbr>                       
                      &<br>
                                                    <wbr>  
                      numBC,PETSC_NULL_INTEGER,     <wbr>                         
                      &<br>
                                                    <wbr>  
                      PETSC_NULL_IS,PETSC_NULL_IS,  <wbr>                          
                      &             !Error here<br>
                                                    <wbr>  
                      PETSC_NULL_IS,section,ierr)<br>
                              CHKERRQ(ierr)<br>
                      <br>
                              call PetscSectionSetFieldName(<wbr>section,0,'flow',ierr)<br>
                              CHKERRQ(ierr)<br>
                      <br>
                              call DMSetDefaultSection(dmda_flow%<wbr>da,section,ierr)<br>
                              CHKERRQ(ierr)<br>
                      <br>
                              call PetscSectionDestroy(section,<wbr>ierr)<br>
                              CHKERRQ(ierr)<br>
                      #endif</p>
                    <p>Thanks,</p>
                    <p>Danyang<br>
                    </p>
                  </div>
                </blockquote>
              </div>
              <br>
              <br clear="all">
              <div><br>
              </div>
              -- <br>
              <div class="gmail_signature">
                <div dir="ltr">
                  <div>
                    <div dir="ltr">
                      <div>What most experimenters take for granted
                        before they begin their experiments is
                        infinitely more interesting than any results to
                        which their experiments lead.<br>
                        -- Norbert Wiener</div>
                      <div><br>
                      </div>
                      <div><a href="http://www.caam.rice.edu/%7Emk51/"
                          target="_blank" moz-do-not-send="true">https://www.cse.buffalo.edu/~knepley/</a><br>
                      </div>
                    </div>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </blockquote>
        <br>
      </blockquote>
      <br>
    </blockquote>
    <br>
  </body>
</html>