On Fri, Mar 4, 2011 at 4:40 PM, <span dir="ltr"><<a href="http://ning.an">ning.an</a>@<a href="http://ghiocel-tech.com">ghiocel-tech.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hello There,<br>
<br>
I am new to PETSc and programming with FORTRAN. For the huge sparse matrix (200,000x200,000 symmetric), it is so slow to set the matrix in PETSc by reading them in matrix market format, which is far beyond our patience. Therefore, I guess that it would be much fast to load the huge matrix, if the matrix is in PETSc binary matrix format <br>
directly.<br></blockquote><div><br></div><div>It is probably slow because you have not preallocated the matrix correctly: <a href="http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#efficient-assembly">http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#efficient-assembly</a></div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Please help on how to write the symmetric matrix in PETSc binary matrix format directly? <br></blockquote><div><br></div><div>You just save it using MatView(). For example:</div><div><br></div><div> <a href="http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/src/ksp/pc/examples/tutorials/ex2.c.html">http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/src/ksp/pc/examples/tutorials/ex2.c.html</a></div>
<div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Both the guidance and examples are welcome. <br>
<br>
Ning</blockquote></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>