Converted document
$\newcommand{\lyxlock}{}$
Subsection 7.1.1: Task Section Up Section 7.1: Optimization Input File Subsection 7.1.3: Parameters Section

### 7.1.2 Options Section

This section defines the control parameters for the optimization. The options that can be defined will depend on the chosen optimization method, which is set with an attribute of the Options section. Currently the two implemented optimization methods are the “Levenberg-Marquardt” method (type=“levmar”) and the “Constrained Levenberg-Marquardt” method (type=“constrained levmar”). Documentation for the Constrained Levenberg-Marquardt method can be found at https://users.ics.forth.gr/~lourakis/levmar/.
Note that this section is optional. When omitted, default values for the control parameters are chosen. The following parameters can be defined.
 Parameter Description Default obj_tol Convergence tolerance for objective function. (1) 0.001 f_diff_scale Forward difference scale factor (2) 0.001 log_level Sets the amount of output that is generated on screen and in the logfile by the FEBio solver (3) LOG_NEVER tau Step size scale factor (4) 1.0e-3 print_level Sets the amount of output generated by the optimization module (5) PRINT_ITERATIONS
For example,
<Options type="constrained levmar">
<obj_tol>0.001</obj_tol>
<f_diff_scale>0.001</f_diff_scale>
<print_level>PRINT_ITERATIONS</print_level>
</Options>