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PETSc comes with Lapack so you can just use dgetrf/dgetri.<br>
<br>
T<br>
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On 11/21/2012 02:23 PM, Gautam Bisht wrote:
<blockquote cite="mid:7D18319F-D93D-45F9-B3AD-CAAAFA773482@lbl.gov"
type="cite">Jed,
<div><br>
<div>
<div>On Nov 21, 2012, at 12:09 PM, Jed Brown wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div class="gmail_extra">On Wed, Nov 21, 2012 at 9:03 PM,
Gautam Bisht <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:gbisht@lbl.gov"
target="_blank">gbisht@lbl.gov</a>></span> wrote:<br>
<div class="gmail_quote">
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<div>I need to compute an inverse of M, a small matrix
(3x3), and am coding in Fortran 90. Following the
suggestion under FAQ on the website, I'm trying to
use MatMatSolve to obtain the inverse of matrix. I
did the following:</div>
<div><br>
</div>
<div>- Created three sequential dense matrices: M, I,
Minv</div>
<div>- Filled values in M and I using MatSetValues</div>
<div>- Tried factoring Matrix M before calling
MatMatSolve(M,I,Minv,ierr)</div>
<div><br>
</div>
<div>I'm not sure what arguments needs to be passed as
arguments in MatLUFactor() corresponding to IS row,
IS col, and MatFactorInfo. I noticed the following
note on website that states "<b>Developer Note:
fortran interface is not autogenerated as the f90
interface defintion cannot be generated correctly
[due to MatFactorInfo]</b>".</div>
<div>Is there a Fortran90 example demonstrating the
use of MatMatSolve()?</div>
</blockquote>
<div><br>
</div>
<div>For a 3x3 matrix, you should just use the explicit
formula for the inverse. Going through the PETSc
interface doesn't make sense at all.</div>
</div>
</div>
</blockquote>
<div><br>
</div>
<div>The 3x3 matrix is being generated using MatMult of 3xN
and Nx3 matrices. I wanted to give MatMatSolve a try, but
could not figure how to use it via Fortran. I will now code
up the explicit formula.</div>
<div><br>
</div>
<blockquote type="cite">
<div class="gmail_extra">
<div class="gmail_quote">
<div> </div>
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<div>Additionally, I have been trying to update my
copy of petsc-dev, and am getting timed out from the
server. </div>
</blockquote>
</div>
<br>
</div>
<div class="gmail_extra">The server died so it has moved to
<a moz-do-not-send="true"
href="https://bitbucket.org/petsc/petsc-dev">https://bitbucket.org/petsc/petsc-dev</a>.</div>
</blockquote>
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<br>
<div><br>
</div>
<div>-Gautam.</div>
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</blockquote>
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