COMSOL Multiphysics™

assemble
matrix contribution (from one element) is A l
= { A l,
ij
} and the currently
assembled global matrix is A = { A ij
} then the entry A ij
is replaced by a zero if
A ij
+ [ A l
] ij
< ε a
max kl
A l,
kl
where [ ] ij
denotes the contribution from a local matrix to the global matrix entry
ij, and where ε a
is the assembly tolerance controlled by the property Assemtol. For
certain types of shape functions the procedure described above is not always safe to
perform. This is the case for shape function elements with degrees of freedoms that
are of different types, for example when a field variable and its spatial derivative is
combined (as in the shherm or sharg_2_5 elements), or when the displacement and
displacement angles are combined (as in some Euler Beam elements in the
Structural Mechanics Module). For this reason, the above process is never used for
local matrix contributions from these types of shape function elements. If the
Assemtol is zero then no elements are neglected, but the removal of zeros are still
performed. If Assemtol is negative, no elements are neglected, and zeros are not
removed from the assembled matrices.
The property Blocksize determines the number of mesh elements that are
assembled together in a vectorized manner. A low value gives a lower memory
consumption, while a high value might give a better performance.
The properties Complexfun and Matherr are described in femsolver.
The property Const gives a list of definitions of constants to be used in evaluations.
This list is a row cell array with alternating constant names and numeric values. This
list is appended to the list given in fem.const. If there is a conflict, the definition
in Const is used.
The properties Eigname and Eigref are described in femeig.
The property Out determines which matrices to output. Ksp is the sparsity pattern
of K. The matrices A, AL, BE, C, and Q are the contributions to the K matrix that
come from the coefficients a, α, β, c, and q, respectively. The vectors F, G, and GA
are the contributions to the L vector that come from the terms f (or F), g (or G),
and γ (or Γ), respectively. The matrix H is the contribution to the N matrix that
comes from the h coefficient. The vector R is the contribution to the M vector that
comes from the r (or R) coefficient. The matrix DA is the contribution to the D
matrix that comes from the d a coefficient. The matrix EA is the contribution to the
E matrix that comes from the e a coefficient.
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