GeneralCut< AVariableManager > Class Template Reference

This class implements a common way to implement cut/selection functionality for arbitrary objects. More...

#include <GeneralCut.h>

Public Member Functions
bool	check (const Object *p) const
	Check if the current cuts are passed by the given object.
void	print () const
	Print cut tree.
std::string	decompile () const
	Do the compilation from a string in return.

Static Public Member Functions
static std::unique_ptr< GeneralCut >	compile (const std::string &cut)
	Creates an instance of a cut and returns a unique_ptr to it, if you need a copy-able object instead you can cast it to a shared_ptr using std::shared_ptr<Variable::Cut>(Cut::compile(cutString))

Private Types
typedef AVariableManager::Object	Object
	Object, that can be checked. This depends on the VariableManager, as the returned variables from the manager must calculate their values on pointers of these objects.
typedef AVariableManager::Var	Var
	Variable returned by the variable manager.

Private Member Functions
	GeneralCut (Nodetuple tuple)
	Constructor of the cut.
	GeneralCut (const GeneralCut &)=delete
	Delete Copy constructor.
GeneralCut &	operator= (const GeneralCut &)=delete
	Delete assign operator.

Private Attributes
std::unique_ptr< const AbstractBooleanNode< AVariableManager > >	m_root
	cut root node

Detailed Description

template<class AVariableManager>
class Belle2::GeneralCut< AVariableManager >

This class implements a common way to implement cut/selection functionality for arbitrary objects.

Every module which wants to perform cuts should use this object. As a parameter the module requires a std::string with the written cut. This std::string has to be passed as an argument to the static Compile method of the Cut class, which returns a unique_ptr to the Cut object. Cuts can be performed via the check method.

Valid cuts can contain:

1. Logic conditions: and, or
2. Numeric conditions: <, <=, >, >=, ==, !=
3. Square brackets [] nesting boolean statements
4. Parenthesis () for grouping expressions
5. Floats
6. Variables registered in the general "Variable Manager" which are used as a template argument to this class.

For example when using the analysis VariableManager for particles, valid cuts are: 1.2 < M < 1.5 daughter(0, M) < daughter(1, M) [M > 1.5 or M < 0.5] and 0.2 < getExtraInfo(SignalProbability) < 0.7

== and != conditions are evaluated not exactly because we deal with floating point values instead two floating point number are equal if their distance in their integral ordering is less than 3.

The general "Variable Manager" passed as a template argument to this class has to have some properties:

• public typedef Object: Which objects can be handled by the variable manager - a pointer on this type ob objects will be required by the check method of the cut.
• public typedef Var: The type of objects, that are returned by the variable manager, when you ask it for a variable (by giving a name to getVariable)
• public static function getInstance: so the variable manager has to be a singleton.
• public function getVariable(const std::string& name): which should return a pointer to an object of type AVariableManager::Var which are used to get the value corresponding to this name. Whenever this value is needed, the function called "function" is called with a pointer to a Object, that is given in the check function of this cut.

The best example for a VariableManager, that has all these parameters, is probably the analysis VariableManager with VariableManager::var equals to the analysis variable and the VariableManager::Object equal to a Particle. For a more slim example of a valid variable manager, see the generalCut.cc test, where a mock variable manager is created.

Definition at line 71 of file GeneralCut.h.

Member Typedef Documentation

Object

typedef AVariableManager::Object Object

private

Object, that can be checked. This depends on the VariableManager, as the returned variables from the manager must calculate their values on pointers of these objects.

Definition at line 73 of file GeneralCut.h.

Var

typedef AVariableManager::Var Var

private

Variable returned by the variable manager.

Definition at line 75 of file GeneralCut.h.

Constructor & Destructor Documentation

GeneralCut()

GeneralCut ( Nodetuple  tuple )

inlineexplicitprivate

Constructor of the cut.

Call init with given Nodetuple

Parameters

tuple

(const boost::python::tuple&) constructed by the python parser from cut.

Definition at line 132 of file GeneralCut.h.

: m_root{NodeFactory::compile_boolean_node<AVariableManager>(tuple)} {}

Member Function Documentation

check()

bool check ( const Object *  p ) const

inline

Check if the current cuts are passed by the given object.

Parameters

p	pointer to the object, that should be checked. All formerly received variables from the variable manager (from the type Var), are asked for their value using var->function(p).

Definition at line 102 of file GeneralCut.h.

    {
      if (m_root != nullptr) return m_root->check(p);
      throw std::runtime_error("GeneralCut m_root is not initialized.");
    }

compile()

static std::unique_ptr< GeneralCut > compile ( const std::string &  cut )

inlinestatic

Creates an instance of a cut and returns a unique_ptr to it, if you need a copy-able object instead you can cast it to a shared_ptr using std::shared_ptr<Variable::Cut>(Cut::compile(cutString))

Parameters

cut	the string defining the cut

Returns

std::unique_ptr<Cut>

Definition at line 84 of file GeneralCut.h.

    {
      // Here we parse
      Py_Initialize();
      try {
        py::object b2parser_namespace = py::import("b2parser");
        py::tuple tuple = py::extract<py::tuple>(b2parser_namespace.attr("parse")(cut));
        return std::unique_ptr<GeneralCut>(new GeneralCut(tuple));
      } catch (py::error_already_set&) {
        PyErr_Print();
        B2FATAL("Parsing error on cutstring:\n" + cut);
      }
    }

decompile()

std::string decompile ( ) const

inline

Do the compilation from a string in return.

In principle, compile(decompile()) should give the same result again.

Definition at line 119 of file GeneralCut.h.

    {
      std::stringstream stringstream;
      stringstream << m_root->decompile();
      return stringstream.str();
    }

print()

void print ( ) const

inline

Print cut tree.

Definition at line 111 of file GeneralCut.h.

    {
      m_root->print();
    }

Member Data Documentation

m_root

std::unique_ptr<const AbstractBooleanNode<AVariableManager> > m_root

private

cut root node

Definition at line 144 of file GeneralCut.h.

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The documentation for this class was generated from the following file:

• framework/utilities/include/GeneralCut.h