Annotation

Annotations are additional information associated to an optimization object (e.g., a constraint or a variable). The Annotation class takes two template arguments: an optimization object type and a value type. For instance, we can create an annotation for constraints of type unsigned int as follows.

Env env;

const unsigned int default_value = 0;

Annotation<Ctr, unsigned int> annotation(env, "my_annotation", default_value);

Note that annotations are global, i.e., they do not relate to a given optimization model and can, therefore, be accessed anywhere in the code. Thus, given a constraint called constraint, the value of the annotation can be accessed by calling the Ctr::get method.

std::cout << "My annotation is " << constraint.get(annotation) << std::endl; // "0", i.e., the default_value value

Annotations are, in particular, used to give decomposition instructions to idol when designing a Branch-and-Price algorithm. To learn more, check our Branch-and-Price tutorials.

template<class ObjectT, class ValueT = unsigned int>
class Annotation : public idol::impl::Annotation

Public Functions

inline Annotation(Env &t_env, std::string t_name)

Constructor.

Creates a new annotation stored in t_env with name t_name. No default value is given.

Parameters:

• t_env – The environment which will store the annotation

• t_name – The given name to the annotation

template<class ...ArgsT>
inline Annotation(Env &t_env, std::string t_name, ArgsT&&... t_args)

Constructor.

Creates a new annotation stored in t_env with name t_name and a default value. The default value is built “in place” by calling the constructor of ValueT with the arguments given after t_name.

Template Parameters:

ArgsT – Parameter pack template types for constructing the default value of the annotation

Parameters:

• t_env – The environment which will store the annotation

• t_name – The given name to the annotation

• t_args – Parameter pack arguments for constructing the default value of the annotation

inline virtual bool is_var_annotation() const override

Returns true if the annotation is for variables, false otherwise.

Returns:

true if the annotation is for variables, false otherwise

inline virtual bool is_ctr_annotation() const override

Returns true if the annotation is for constraints, false otherwise.

Returns:

true if the annotation is for constraints, false otherwise

inline const ValueT &default_value() const

Returns the default value of the annotation.

Returns:

The default value of the annotation

inline unsigned int id() const

Returns the id of the annotation.

The id is unique within the environment.

Returns:

The id of the annotation

inline const std::string &name() const

Returns the given name of the annotation.

Returns:

The given name of the annotation

inline bool has_default() const

Returns true if the annotation has a default value, false otherwise.

Returns:

true if the annotation has a default value, false otherwise

void free()

Frees the memory kept for the annotation in the environment.

inline Env &env() const

Returns the underlying environment of the annotation.

Returns:

The underlying environment of the annotation.

Public Static Functions

template<class ...ArgsT>
static inline Annotation<ObjectT, ValueT> make_with_default_value(Env &t_env, std::string t_name, ArgsT&&... t_args)

Creates a new annotation stored in t_env with name t_name and a default value. The default value is built “in place” by calling the constructor of ValueT with the arguments given after t_name.

Template Parameters:

ArgsT – Parameter pack template types for constructing the default value of the annotation

Parameters:

• t_env – The environment which will store the annotation

• t_name – The given name to the annotation

• t_args – Parameter pack arguments for constructing the default value of the annotation

Returns:

The created annotation