11 nonlinear_equation_solvers (beta)
Defines parameters for nonlinear equation solution strategies.
Name 
 Type 
 Description 
 Default 
label (beta) 
 STRING 
 The user defined identifier for this nonlinear solution method. 
 
 SUB OBJECT 
 See linked documentation 

Example Usage:nonlinear_equation_solvers: [ { label: "newton_raphson", newton: { target_relative_residual: 0.001, linear_equation_solver: "direct_multifrontal", maximum_iterations: 8 } } ]
11.1 newton (beta)
Defines options for the Newton nonlinear solver method.
Name 
 Type 
 Description 
 Default 
target_relative_residual [optional] (beta) 
 DOUBLE 
 The target relative residual for the nonlinear iteration that, upon reaching, signals successful convergence of the iteration. The relative residual is computed as the relative decrease in the current residual norm from the initial residual norm. The default value is overly conservative for most problems, and can usually be increased to improve speed and robustness. 
 1e8 
linear_equation_solver (beta) 
 STRING 
 The user defined identifier of the linear solver to use. When a direct linear solver is used, the Newton method is often called a “NewtonRaphson” method. When a Krylov iterative linear solver is used, the Newton method is often called a “NewtonKrylov” method. 
 
maximum_iterations [optional] (beta) 
 NONNEGATIVE INTEGER 
 Set the maximum number of iterations. 
 8 
use_line_search [optional] (alpha) 
 truefalse 
 This enables a backtracking line search, which dynamically reduces the step size within Newton iteration to avoid divergence. However, it is often overly conservative in its step size reduction, and may slow down analysis significantly, even on steps that would otherwise converge quickly. It is recommended to try adaptive time stepping and review other aspects of the problem setup before enabling this option. This option typically requires a higherthandefault value for maximum_iterations to converge. 
 false 
Example Usage:newton: { target_relative_residual: 0.001, linear_equation_solver: "direct_multifrontal", maximum_iterations: 8 }