DOLFIN User Manual - FEniCS Project

DOLFIN User ManualHoffman, Jansson, Logg, Wellsbeing modified. An error message is printed through the log system if thereis no parameter with the given key in the database.The following examples illustrate the use of set():set(‘‘tolerance’’, 0.01);set(‘‘number of samples’’, 10);set(‘‘solve dual problem’’, true);set(‘‘file name’’, ‘‘solution.xml’’);Note that changing the values of parameters using set() does not changethe values of already retrieved parameters; it only changes the values ofparameters in the database. Thus, the value of a parameter must be changedbefore using a component that is controlled by the parameter in question.11.3 Adding a new parameterTo add a parameter to the database, use the function add() available in thedolfin namespace:void add(std::string key, Parameter value);This function accepts two arguments: a unique key identifying the new parameterand the value of the new parameter.The following examples illustrate the use of add():add(‘‘tolerance’’, 0.01);add(‘‘number of samples’’, 10);add(‘‘solve dual problem’’, true);add(‘‘file name’’, ‘‘solution.xml’’);75