Parameters¶

class dolfin.cpp.common.Parameters(*args, **kwargs)¶

Bases: object

This class stores a set of parameters. Each parameter is identified by a unique string (the key) and a value of some given value type. Parameter sets can be nested at arbitrary depths. A parameter may be either int, double, string or boolean valued. Parameters may be added as follows:

Parameters p("my_parameters");
p.add("relative_tolerance",  1e-15);
p.add("absolute_tolerance",  1e-15);
p.add("gmres_restart",       30);
p.add("monitor_convergence", false);

Parameters may be changed as follows:

p["gmres_restart"] = 50;

Parameter values may be retrieved as follows:

int gmres_restart = p["gmres_restart"];

Parameter sets may be nested as follows:

Parameters q("nested_parameters");
p.add(q);

Nested parameters may then be accessed by

p("nested_parameters")["..."]

Parameters may be nested at arbitrary depths. Parameters may be parsed from the command-line as follows:

p.parse(argc, argv);

Note: spaces in parameter keys are not allowed (to simplify usage from command-line).

Initialize Parameters

Usage:

Parameters(): create empty parameter set
Parameters(name): create empty parameter set with given name
Parameters(other_parameters): create copy of parameter set
Parameters(name, dim=3, tol=0.1, foo=”Foo”): create parameter set with given parameters
Parameters(name, dim=(3, 0, 4), foo=(“Foo”, [“Foo”, “Bar”]): create parameter set with given parameters and ranges

add(*args)¶: Add a parameter to the parameter set

add_unset()¶

Add unset parameter of specified type.

Parameters:	key (std::string) – type (Parameter::Type) –
Return type:	void

assign()¶

Assignment operator.

Parameters:	Parameters & parameters (const) –
Return type:	const Parameters &

clear()¶

Clear parameter set.

Return type:	void

copy()¶: Return a copy of it self

find_parameter()¶

Return parameter, if present.

Parameters:	key (std::string) –
Return type:	boost::optional< Parameter & >

find_parameter_set()¶

Return parameter set, if present.

Parameters:	key (std::string) –
Return type:	boost::optional< Parameters & >

get(key)¶

Return all data available for a certain parameter

The data is returned in a tuple: value, range, access_count, change_count = parameters.get(‘name’)

get_range(key)¶: Get the range for the given parameter

has_key()¶

Check if parameter set has key (parameter or nested parameter set)

Parameters:	key (std::string) –
Return type:	bool

has_parameter()¶

Check if parameter set has given parameter.

Parameters:	key (std::string) –
Return type:	bool

has_parameter_set()¶

Check if parameter set has given nested parameter set.

Parameters:	key (std::string) –
Return type:	bool

items()¶

iterdata()¶: Returns an iterator of a tuple of a parameter key together with its value

iteritems()¶: Returns an iterator over the (key, value) items of the Parameters

iterkeys()¶: Returns an iterator for the parameter keys

itervalues()¶: Returns an iterator to the parameter values

keys()¶: Returns a list of the parameter keys

name()¶

Return name for parameter set.

Return type:	std::string

option_string()¶: Return an option string representation of the Parameters

parse(argv=None)¶: Parse command line arguments

remove()¶

Remove parameter or parameter set with given key.

Parameters:	key (std::string) –
Return type:	void

rename()¶

Rename parameter set.

Parameters:	key (std::string) –
Return type:	void

set_range(key, *arg)¶: Set the range for the given parameter

size()¶

Interface for pybind11 iterators.

Return type:	std::size_t

str()¶

Return informal string representation (pretty-print)

Parameters:	verbose (bool) –
Return type:	std::string

thisown¶: The membership flag

to_dict()¶: Convert the Parameters to a dict

update(other)¶: A recursive update that handles parameter subsets correctly.

values()¶: Returns a list of the parameter values