[tag] tikhonov

Defines the configuration for Tikhonov regularization in the Newton nonlinear solver.

The Tikhonov regularization adds a value to the diagonal of the Jacobian matrix to improve convergence behaviour for ill-conditioned systems.

Example:**

<tikhonov>
    <lambda>1e-14</lambda>
    <starting_iteration>11</starting_iteration>
</tikhonov>

The Tikhonov regularization is only applied starting from the iteration specified by starting_iteration to avoid interfering with the initial convergence phase.

Child parameters, attributes and cases

• [tag] lambda
• [tag] starting_iteration

Additional info

From NumLib/ODESolver/CreateNonlinearSolver.cpp line 116

• This is an optional parameter.
• Expanded tag path: nonlinear_solvers.nonlinear_solver.tikhonov
• Go to source code: → ogs/ogs/6.5.9

Used in the following test data files

• [→ ogs/ogs/master | → doc] TH2M/TH2/heatpipe/heat_pipe_strict.prj