ultra::terminal Class Reference

#include <terminal.h>

Inheritance diagram for ultra::terminal:

Public Member Functions
virtual value_t	instance () const =0
std::string	to_string (format=c_format) const override
	symbol (const std::string &, category_t=default_category)
Public Member Functions inherited from ultra::symbol
	symbol (const std::string &, category_t=default_category)
virtual	~symbol ()=default
	Virtual destructor to allow safe polymorphic deletion.
category_t	category () const noexcept
opcode_t	opcode () const noexcept
const std::string &	name () const noexcept
void	category (category_t) noexcept
virtual bool	is_valid () const

Additional Inherited Members
Public Types inherited from ultra::symbol
enum	format { c_format , cpp_format , python_format , sup_format }
	Supported rendering formats for symbol stringification.
using	category_t = unsigned
using	opcode_t = unsigned
Static Public Attributes inherited from ultra::symbol
static constexpr category_t	default_category = 0
	Default category assigned when typing is not used.
static constexpr category_t	undefined_category
	Sentinel value indicating that the category has not yet been assigned.

Detailed Description

Leaf symbol in a genetic programming expression.

A terminal represents an atomic value in a GP expression tree or linear program. Unlike functions, terminals do not take arguments and therefore have arity zero.

Typical examples of terminals include:

• input variables (e.g. program inputs or features);
• constant literals;
• nullary functions (functions with no parameters).

Terminals are evaluated by directly producing a value, rather than combining the results of sub-expressions. As such, they always appear as leaves in the program structure.

See also

symbol

Examples

symbolic_regression03.cc.

Member Function Documentation

instance()

virtual value_t ultra::terminal::instance ( ) const

nodiscardpure virtual

Produce the runtime value of the terminal.

Returns

the value associated with this terminal

This function returns the value represented by the terminal when the program is evaluated. The returned value may depend on the evaluation context (e.g. the current input vector), but does not depend on any child expressions.

Note

Implementations must not throw exceptions and should be side-effect free to preserve referential transparency during program evaluation.

Implemented in ultra::de::real, ultra::ga::integer, ultra::hga::integer, ultra::hga::permutation, ultra::integer::literal, ultra::integer::number, ultra::nullary, ultra::real::integer, ultra::real::literal, ultra::real::number, ultra::src::variable, and ultra::str::literal.

Examples

symbolic_regression03.cc.

symbol()

ultra::symbol::symbol ( const std::string & name, category_t c = default_category )

explicit

Constructs a symbol with the given name and category.

Parameters

[in]	name	name of the symbol (unique textual identifier)
[in]	c	category of the symbol

Warning

The symbol name is used for serialisation and must be globally unique within a symbol set. While opcodes are also unique, they are assigned dynamically and may differ between executions.

to_string()

std::string ultra::terminal::to_string ( format = c_format ) const

inlinenodiscardoverridevirtual

Implements ultra::symbol.

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

• terminal.h