COMSOL Multiphysics™

femnlin
The property Rstep sets a restriction for the damping factor update in the Newton
iteration. Each time the damping factor is updated, it is allowed to change at most
by a factor Rstep.
If the property Stop is set to on, the solver gives an output even if the algorithm
fails at some point. If the parameter stepping feature is used with more than one
parameter value, the output contains the solutions for the parameters that were
successfully computed. Otherwise, the output is the nonconverged solution
corresponding to the iteration where the failure occurred. If Stop is set to off, the
solver terminates with an error if the algorithm fails.
Use the property Stopcond to make sure the solver stops before a certain event. You
provide a scalar expression that is evaluated after each parameter step. The parameter
stepping is stopped if the real part of the expression is evaluated to something
negative. The corresponding solution, for which the expression is negative is not
returned.
For more information about the nonlinear stationary solver, see “The Stationary
Solver” on page 377 in the COMSOL Multiphysics User’s Guide.
Diagnostics
If the Newton iteration does not converge, the error messages Maximal number of
iterations reached or Damping factor too small are displayed. If during the
solution process NaN or Inf elements are encountered in the solution even after
reducing the damping factor to the minimum, the error message Inf or NaN
repeatedly found in solution is printed. The message Underflow of
parameter step length means that the Newton iterations did not converge, even
after reducing the parameter step length to the limit given in Pminstep. This
probably means that the curve of solutions has a turning point or bifurcation point
close to the current parameter value and solution.
Compatibility The property Variables has been renamed to Const in FEMLAB 2.3.
The properties Epoint and Tpoint are obsolete from FEMLAB 2.2. Use
fem.***.gporder to specify integration order.
The property/value Jacobian/Lumped has been made obsolete from FEMLAB
1.1.
The properties Toln and Normn have been made obsolete from FEMLAB 1.2. Ntol
replaces Toln.
See Also
assemble, asseminit, femlin, femsolver, femstatic, femstruct
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