Dear All,
I am trying to understand the implementation of Hermite element
and have a problem with the following fragment of the method:
void hermite_segment__::mat_trans(/* skip *)
gmm::copy(gmm::identity_matrix(), M);
// gradient at point 0
gmm::mult(G, pgp->grad(1), K);
if (N == 1) M(1, 1) = K(0,0);
else M(1, 1) = gmm::mat_euclidean_norm(K)
* gmm::sgn(gmm::vect_sp(gmm::mat_col(K, 0), r));
// gradient at point 1
if (!(pgt->is_linear())) gmm::mult(G, pgp->grad(3), K);
if (N == 1) M(3, 3) = K(0,0);
else M(3, 3) = gmm::mat_euclidean_norm(K)
* gmm::sgn(gmm::vect_sp(gmm::mat_row(K, 0), r));
Why the scheme for gradient at point 0 and 1 differ -- that is why
in case of point 1 we take gmm:mat_row(K,0) and not gmm::mat_col(K,0)?
Isn't the matrix K of the size Nx1 where N is the dimension of the
real space?
And also this computatno with signum function -- are they to take into
account the order of poins in respet to the local coordinate system?
I would appreciate any hint.
Regards
Roman
--
Roman Putanowicz, PhD < [email protected] >
Institute for Computational Civil Engng (L-5)
Dept. of Civil Engng, Cracow Univ. of Technology
www.l5.pk.edu.pl, tel. +48 12 628 2569, fax 2034
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