Function newton_rootfinder::xml_parser::from_xml_jacobian

pub fn from_xml_jacobian(
    filepath: &str
) -> (SolverParameters, Vec<IterativeParams>, Vec<NormalizationMethod>, Vec<NormalizationMethod>)

Parser for a solver operating with a model with the jacobian provided

XML structure

Root

It is expected to be an .xml document with a root node called nrf (newton root finder)

Three child nodes are expected:

 <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
 <nrf>
     <solver>...</solver>
     <iteratives>...</iteratives>
     <residuals>...</residuals>
 </nrf>

Solver node

The <solver> node contains must contains the parameters of the SolverParameters struct, i.e :

• max_iter
• damping (true or false)
• tolerance
• problem_size
• resolution_method: (see crate::solver::ResolutionMethod)
  • “NR” for Newton-Raphson
  • “SN” for Stationary Newton
  • “BROY1” for Broyden First Method approximating the jacobian
  • “BROY2” for Broyden Second Method approximating the jacobian
  • “GRST1” for Greenstadt First Method approximating the jacobian
  • “GRST2” for Greenstadt Second Method approximating the jacobian
  • “BROY1_INV” for Broyden First Method approximating the inverse jacobian
  • “BROY2_INV” for Broyden Second Method approximating the inverse jacobian
  • “GRST1_INV” for Greenstadt First Method approximating the inverse jacobian
  • “GRST2_INV” for Greenstadt Second Method approximating the inverse jacobian

 <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
 <nrf>
     <solver problem_size="2" max_iter="60" tolerance="1e-6" damping="true" resolution_method="NewtonRaphson"/>
     <iteratives>...</iteratives>
     <residuals>...</residuals>
 </nrf>

Iteratives node

The <iteratives> node contains all the default values for the parameters of the IterativeParams constructor:

• min_value
• max_value
• max_step_abs
• max_step_rel

Its childen will be the node, each of them having an id starting at zero. Each children will either take the default values if none are provided, or take any that are redefined for the given id.

 <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
 <nrf>
     <solver>...</solver>
     <iteratives min_value="-inf" max_value="inf" max_step_abs="inf" max_step_rel="inf">
         <iterative id="0">
         <iterative id="1" max_step_abs="100">
     </iteratives>
     <residuals>...</residuals>
 </nrf>

The first one will take the default values, the second also except for max_step_abs that will be equal to 100.

Residuals node

The <residuals> node contains all the default values for the parameters of the ResidualConfig constructor:

• stopping_criteria
• update_method

Its childen will be the node, each of them having an id starting at zero. Each children will either take the default values if none are provided, or take any that are redefined for the given id.

 <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
 <nrf>
     <solver>...</solver>
     <iteratives>...</iteratives>
     <residuals stopping_criteria="Adapt"  update_method="Abs">
         <residual id="0">
         <residual id="1" stopping_criteria="Abs">
     </residuals>
 </nrf>

The first one will take the default values, the second also except for stopping_criteria that will be equal to Abs.

Trick

You can add any attribute that is not used by the parser, for example if you want to name variables to recognize them:

 <iterative id="0" var_name="myVarName">

Examples

 use newton_rootfinder as nrf;

 const FILEPATH: &'static str = "./my_path/my_configuration_file.xml";
 let (solver_parameters, iteratives_vec, stopping_criterias, update_methods) =
    nrf::xml_parser::from_xml_finite_diff(&FILEPATH);

 let iteratives = nrf::iteratives::Iteratives::new(&iteratives_vec);
 let residuals_config =
    nrf::residuals::ResidualsConfig::new(&stopping_criterias, &update_methods);
 let problem_size = solver_parameters.get_problem_size();

 let init = nalgebra::DVector::zeros(5);

 let mut rf = nrf::solver::RootFinder::new(
    solver_parameters,
    init,
    &iteratives,
    &residuals_config,
 );