COMSOL Multiphysics™

femlin
KN T
N 0
U – U 0
Λ
=
L
M ,
where K, N, L, and M are evaluated for U=U 0 . Thus, if the original problem is linear
and K is the correct Jacobian, femlin computes the solution of the original
problem. The linearization “point” U 0 can be specified with the property U.
femlin can also partially solve the eigenvalue problem:
in that it transforms the problem using one of the constraint-handling methods.
Here λ is the eigenvalue, the name can be controlled by the propery eigname. λ 0 is
the eigenvalue linearization point, the value can be controlled by the property
eigref.
The function femlin accepts the following property/values:
TABLE 1-25: VALID PROPERTY/VALUE PAIRS
PROPERTY
NAME
PROPERTY VALUE DEFAULT DESCRIPTION
Eigname string lambda Eigenvalue name
Eigref string 0 Linearization point for the
eigenvalue
In
cell array of names N and M are Input matrices
and matrices K | L | M
| N | D | E
empty,
D=E=0
Itol positive scalar 1e-6 Relative tolerance for
linear iterative solver
Keep
string containing K, N
| auto
auto
Parameter-independent
quantities
Oldcomp cell array of strings Old parameter
components
Out
U – ( λ – λ 0
)DU + ( λ–
λ 0
) 2 EU = – N T
NU = M
fem | sol | u | plist
| stop | solcompdof
| Kc | Lc | Dc | Ec |
Null | Nnp | ud |
uscale | nullfun |
symmetric | cell
array of these strings
sol
Output variables
125