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<div class="moz-cite-prefix">Hi Oliver,<br>
</div>
<blockquote cite="mid:529DBC69.3040308@igpm.rwth-aachen.de"
type="cite">
<pre wrap="">I am using
FieldMatrix< double, 2, 2 > Id = ScaledIdentityMatrix< double, 2 >(1);
for that. That works just as well.</pre>
</blockquote>
That is indeed true. The ScaledIdentityMatrix correctly implements
the method istl_to_fmatrix(), something other users have struggled
with. IdentityMatrix only provides the standard C++ cast operator,
which is more convenient and which was part of our discussion
concerning the "const dense matrix" interface. You are right, I did
add IdentityMatrix for documenting this new behavior.
<blockquote cite="mid:529DBC69.3040308@igpm.rwth-aachen.de"
type="cite">
<blockquote type="cite">
<pre wrap="">Then, IdentityMatrix may be used as the return type of the methods jacobianTransposed() and jacobianInverseTransposed(); for some grids, the LocalGeometry's jacobians reduce to an identity matrix.
</pre>
</blockquote>
<pre wrap="">
When would that happen? If LocalGeometry's jacobian is the identity that means that codim<0> entities are copies
of their fathers. And since the JacobianType is static _all_ entities would be copies of their fathers.
What would I need such a grid for?
</pre>
</blockquote>
My bad, it is indeed somewhat more special. In PrismGrid, the upper
and lower intersections of a grid element are images of the
lower-dimensional host element after a translation. Lateral and
horizontal intersections have individual geometry implementations,
and I use dynamic polymorphism for choosing the correct local
geometry implementation in the methods geometryInInside(),
geometryInOutside(). Only for horizontal intersections the jacobians
are the identity. I understand this is a very obscure example...<br>
<br>
Cheers,<br>
Christoph<br>
<br>
<div class="moz-signature">-- <br>
<title></title>
<font color="#666666"><small>Christoph Gersbacher</small><small>
<a
href="mailto:christoph.gersbacher@mathematik.uni-freiburg.de"><font
color="#3333ff"><christoph.gersbacher@mathematik.uni-freiburg.de></font></a></small><br>
</font>
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