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This is what I used before for a long time until now when I updated
PETSc and it started to complain "New nonzero caused a malloc!" when
I wanted to add some new nonzero outside of the original
nnz-pattern. MatDuplicate is always retaining the pattern, isn't it?<br>
Vaclav<br>
<br>
On 03/02/2012 12:06 AM, Matthew Knepley wrote:
<blockquote
cite="mid:CAMYG4GndtfuW_4FFU48v89E=f5MVcg25VBjfrZTDQy9S18AbqQ@mail.gmail.com"
type="cite">On Thu, Mar 1, 2012 at 5:03 PM, Vaclav Hapla <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:vaclav.hapla@vsb.cz">vaclav.hapla@vsb.cz</a>></span>
wrote:<br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
Dear PETSc team,<br>
why I am not able to do this:<br>
<br>
...<br>
MatCreate(PETSC_COMM_SELF, &Kreg);<br>
MatSetSizes(Kreg,m,n,m,n);<br>
MatSetType(Kreg, MATSEQAIJ);<br>
MatSeqAIJSetPreallocation(Kreg,0,nnz);<br>
MatAssemblyBegin(Kreg, MAT_FINAL_ASSEMBLY);<br>
MatAssemblyEnd( Kreg, MAT_FINAL_ASSEMBLY);<br>
PetscFree(nnz);<br>
{<br>
PetscInt nz_Kreg;<br>
MatGetRow(Kreg, 0, &nz_Kreg, PETSC_IGNORE,
PETSC_IGNORE);<br>
PetscPrintf(PETSC_COMM_SELF, "nnz %d Kreg %d\n", nnz[0],
nz_Kreg); // prints nnz 11 Kreg 0 !!!<br>
}<br>
MatCopy(K_loc, Kreg, DIFFERENT_NONZERO_PATTERN); //fails: New
nonzero at (0,0) caused a malloc!<br>
</blockquote>
<div><br>
</div>
<div>I think you want</div>
<div><br>
</div>
<div><a moz-do-not-send="true"
href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatDuplicate.html">http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatDuplicate.html</a></div>
<div><br>
</div>
<div>which does it in one line.</div>
<div><br>
</div>
<div> Matt</div>
<div> </div>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<br>
PETSc complains about new nonzero - not surprisingly because
MatAssemblyBegin/End filters zeros as I understand.<br>
But when I comment out MatAssemblyBegin/End, MatCopy complains
that it is only for assembled matrices.<br>
<br>
I think that to call MatSetValues on all allocated nonzeros
just to make them survive MatAssemblyBegin/End or to replace
MatCopy call by loop over raw array is both quite awkward.<br>
Maybe one should be able to turn the filter in
MatAssemblyBegin/End off. Or is there any other way out?<br>
<br>
BTW, what I need is to make a copy Kreg of given matrix K_loc
but with few additional preallocated positions which are
filled later. Is there some other convenient solution?<br>
<br>
Cheers,<br>
Vaclav Hapla<br>
</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
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<br>
</blockquote>
<br>
<br>
<div class="moz-signature">-- <br>
<p style="font-size: 11pt; font-family: Verdana,sans-serif;">
Vaclav Hapla<br>
Research assistant<br>
<a href="http://spomech.vsb.cz/">SPOMECH project</a><br>
<a href="http://www.it4i.eu/">Centre of Excellence
IT4Innovations</a>
</p>
<p style="font-size: 11pt; font-family: Verdana,sans-serif;">
tel.: (+420) 59 732 6291<br>
VSB-Technical University of Ostrava<br>
17.listopadu 15/2172<br>
708 33 Ostrava-Poruba<br>
Czech Republic<br>
</p>
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