COMSOL Multiphysics™

femtime
Purpose
femtime
Solve time-dependent PDE problem.
Syntax
Description
fem.sol = femtime(fem,'Tlist',[t1 ... tn],...)
fem = femtime(fem,'Tlist',[t1 ... tn],'Out',{'fem'},...)
fem.sol = femtime('in',{'K' K 'N' N 'L' L 'M' M 'D' D 'E' E},...
'Tlist',[t1 ... tn],...)
fem.sol = femtime(fem,...) solves a time-dependent PDE problem.
The PDE problem is stored in the (possibly extended) FEM structure fem. See
femstruct for details. The time interval and possible intermediate time values are
given in the property Tlist. The output times are controlled by the property Tout.
fem.sol = femtime('in',{'K' K 'N' N 'L' L 'M' M 'D' D 'E' E}) solves
the pre-assembled linear problem
The function femtime accepts the following property/values:
TABLE 1-39: VALID PROPERTY/VALUE PAIRS
PROPERTY VALUES DEFAULT DESCRIPTION
Atol See below 1E-3 Absolute tolerance
Complex on | off off Complex numbers
Consistent off | on | bweuler bweuler Consistent
initialization of DAE
systems
Estrat 0 | 1 0 Error estimation
strategy
In
cell array of names and N and M are Input matrices
matrices K | L | M | N |
D | E
empty,
D=E=0
Initialstep positive scalar Initial time step
Keep string containing K, L,
M, N, D, E | auto
EU·· + DU·
+ KU = L – N T Λ
NU = M
auto
Time-independent
quantities
MassSingular yes | maybe maybe Singular mass matrix
Maxorder integer between 1 and 5 Maximum BDF order
5
Maxstep positive scalar Maximum time step
167