UserFunction Class Reference

A user defined mathematical function. More...

#include <Function.h>

Inheritance diagram for UserFunction:

Public Member Functions
	UserFunction (string cat_, string name_, string formula_, bool is_local=true, int argc_=-1, string title_="", string descr_="", int max_argc_=0, bool is_active=true)
	UserFunction (const UserFunction *function)
void	set (const ExpressionItem *item)
ExpressionItem *	copy () const
string	formula () const
string	internalFormula () const
int	calculate (MathStructure &mstruct, const MathStructure &vargs, const EvaluationOptions &eo)
void	setFormula (string new_formula, int argc_=-1, int max_argc_=0)
void	addSubfunction (string subfunction, bool precalculate=true)
void	setSubfunction (size_t index, string subfunction)
void	delSubfunction (size_t index)
void	clearSubfunctions ()
size_t	countSubfunctions () const
void	setSubfunctionPrecalculated (size_t index, bool precalculate)
const string &	getSubfunction (size_t index) const
bool	subfunctionPrecalculated (size_t index) const
int	subtype () const
Public Member Functions inherited from MathFunction
	MathFunction (string name_, int argc_, int max_argc_=0, string cat_="", string title_="", string descr_="", bool is_active=true)
	MathFunction (const MathFunction *function)
virtual int	type () const
bool	testArgumentCount (int itmp)
virtual MathStructure	calculate (const string &eq, const EvaluationOptions &eo=default_evaluation_options)
virtual MathStructure	parse (const string &eq, const ParseOptions &po=default_parse_options)
virtual int	parse (MathStructure &mstruct, const string &eq, const ParseOptions &po=default_parse_options)
virtual MathStructure	calculate (MathStructure &vargs, const EvaluationOptions &eo=default_evaluation_options)
string	condition () const
string	printCondition ()
void	setCondition (string expression)
bool	testCondition (const MathStructure &vargs)
int	args () const
int	minargs () const
int	maxargs () const
int	args (const string &str, MathStructure &vargs, const ParseOptions &po=default_parse_options)
size_t	lastArgumentDefinitionIndex () const
Argument *	getArgumentDefinition (size_t index)
void	clearArgumentDefinitions ()
void	setArgumentDefinition (size_t index, Argument *argdef)
int	stringArgs (const string &str, vector< string > &svargs)
void	setDefaultValue (size_t arg_, string value_)
const string &	getDefaultValue (size_t arg_) const
void	appendDefaultValues (MathStructure &vargs)
MathStructure	produceVector (const MathStructure &vargs, int begin=-1, int end=-1)
MathStructure	produceArgumentsVector (const MathStructure &vargs, int begin=-1, int end=-1)
virtual bool	representsPositive (const MathStructure &, bool=false) const
virtual bool	representsNegative (const MathStructure &, bool=false) const
virtual bool	representsNonNegative (const MathStructure &, bool=false) const
virtual bool	representsNonPositive (const MathStructure &, bool=false) const
virtual bool	representsInteger (const MathStructure &, bool=false) const
virtual bool	representsNumber (const MathStructure &, bool=false) const
virtual bool	representsRational (const MathStructure &, bool=false) const
virtual bool	representsReal (const MathStructure &, bool=false) const
virtual bool	representsComplex (const MathStructure &, bool=false) const
virtual bool	representsNonZero (const MathStructure &, bool=false) const
virtual bool	representsEven (const MathStructure &, bool=false) const
virtual bool	representsOdd (const MathStructure &, bool=false) const
virtual bool	representsUndefined (const MathStructure &) const
virtual bool	representsBoolean (const MathStructure &) const
virtual bool	representsNonMatrix (const MathStructure &) const
Public Member Functions inherited from ExpressionItem
	ExpressionItem (string cat_, string name_, string title_="", string descr_="", bool is_local=true, bool is_builtin=false, bool is_active=true)
virtual bool	destroy ()
bool	isRegistered () const
void	setRegistered (bool is_registered)
	For internal use.
virtual const string &	name (bool use_unicode=false, bool(*can_display_unicode_string_function)(const char *, void *)=NULL, void *can_display_unicode_string_arg=NULL) const
virtual const string &	referenceName () const
virtual const ExpressionName &	preferredName (bool abbreviation=false, bool use_unicode=false, bool plural=false, bool reference=false, bool(*can_display_unicode_string_function)(const char *, void *)=NULL, void *can_display_unicode_string_arg=NULL) const
virtual const ExpressionName &	preferredInputName (bool abbreviation=false, bool use_unicode=false, bool plural=false, bool reference=false, bool(*can_display_unicode_string_function)(const char *, void *)=NULL, void *can_display_unicode_string_arg=NULL) const
virtual const ExpressionName &	preferredDisplayName (bool abbreviation=false, bool use_unicode=false, bool plural=false, bool reference=false, bool(*can_display_unicode_string_function)(const char *, void *)=NULL, void *can_display_unicode_string_arg=NULL) const
virtual const ExpressionName &	getName (size_t index) const
virtual void	setName (const ExpressionName &ename, size_t index=1, bool force=true)
virtual void	setName (string sname, size_t index, bool force=true)
virtual void	addName (const ExpressionName &ename, size_t index=0, bool force=true)
virtual void	addName (string sname, size_t index=0, bool force=true)
virtual size_t	countNames () const
virtual void	clearNames ()
virtual void	clearNonReferenceNames ()
virtual void	removeName (size_t index)
virtual size_t	hasName (const string &sname, bool case_sensitive=true) const
virtual size_t	hasNameCaseSensitive (const string &sname) const
virtual const ExpressionName &	findName (int abbreviation=-1, int use_unicode=-1, int plural=-1, bool(*can_display_unicode_string_function)(const char *, void *)=NULL, void *can_display_unicode_string_arg=NULL) const
virtual const string &	title (bool return_name_if_no_title=true, bool use_unicode=false, bool(*can_display_unicode_string_function)(const char *, void *)=NULL, void *can_display_unicode_string_arg=NULL) const
virtual void	setTitle (string title_)
virtual const string &	description () const
virtual void	setDescription (string descr_)
virtual const string &	category () const
virtual void	setCategory (string cat_)
virtual bool	hasChanged () const
virtual void	setChanged (bool has_changed)
virtual bool	isLocal () const
virtual bool	setLocal (bool is_local=true, int will_be_active=-1)
virtual bool	isBuiltin () const
virtual bool	isApproximate () const
virtual void	setApproximate (bool is_approx=true)
virtual int	precision () const
virtual void	setPrecision (int prec)
virtual bool	isActive () const
virtual void	setActive (bool is_active)
virtual bool	isHidden () const
virtual void	setHidden (bool is_hidden)
virtual int	refcount () const
virtual void	ref ()
virtual void	unref ()
virtual void	ref (ExpressionItem *o)
virtual void	unref (ExpressionItem *o)
virtual ExpressionItem *	getReferencer (size_t index=1) const
virtual bool	changeReference (ExpressionItem *o_from, ExpressionItem *o_to)

Protected Attributes
string	sformula
string	sformula_calc
vector< string >	v_subs
vector< bool >	v_precalculate
Protected Attributes inherited from MathFunction
int	argc
int	max_argc
vector< string >	default_values
unordered_map< size_t, Argument * >	argdefs
size_t	last_argdef_index
string	scondition
Protected Attributes inherited from ExpressionItem
string	scat
string	stitle
string	sdescr
bool	b_local
bool	b_changed
bool	b_builtin
bool	b_approx
bool	b_active
bool	b_registered
bool	b_hidden
bool	b_destroyed
int	i_ref
int	i_precision
vector< ExpressionItem * >	v_refs
vector< ExpressionName >	names

Additional Inherited Members
Protected Member Functions inherited from MathFunction
bool	testArguments (MathStructure &vargs)
virtual MathStructure	createFunctionMathStructureFromVArgs (const MathStructure &vargs)
virtual MathStructure	createFunctionMathStructureFromSVArgs (vector< string > &svargs)

Detailed Description

A user defined mathematical function.

User functions are functions defined using expression strings, representing mathematical formulas.

The expression/formula of a function is basically a normal expression with placeholders for arguments. These placeholders consists of a backslash and a letter — x, y, z for the 1st, 2nd and 3rd arguments and a to u for argument 4 to 24. They are replaced by entered arguments when a function is calculated. The placeholders naturally also decide the number of arguments that a function requires. For example the function for triangle area ("base * height / 2") has the name triangle and the formula "(\x*\y)/2", which gives that "triangle(2, 3)" equals "(2*3) / 2" and returns "3" as result. An argument can be used more than one time and all arguments must not necessarily be in order in the formula.

Additionally, optional arguments can be put in the formula with upper-case (X, Y, Z, ...) instead of lower-case letters (x, y, z, ...). The default value can be put in brackets after the letter (ex. "\X{2}"). The default value may be omitted and is then zero. All additional arguments after an optional argument must also be optional.

To simplify the formula and make it more efficient, subfunctions can be used. These works just like the main formula, using the arguments of it. Subfunctions are referenced in the formula using ('\2', '\2', '\3', ...). Even though it would be quite meaningless, the formula for triangle function could for example have a subfunction "\x*\y" and the formula "\1/2". Subfunctions must be added before the main formula is set.

Member Function Documentation

int UserFunction::calculate ( MathStructure &  mstruct, const MathStructure &  vargs, const EvaluationOptions &  eo  )

virtual

The main function for subclasses to reimplement. Calculates a value from arguments in vargs and puts it in mstruct.

This function expects the number of arguments to be equal to the maximum number of arguments, and checked by the argument definitions.

If the return value is negative, then argument -(return value) has been evaluated in mstruct. If -(return value) is greater than max arguments, then mstruct is a vector of evaluated argument values.

Parameters

[out]	mstruct	Structure that is set with the result of the calculation.
	vargs	Arguments passed to the mathematical function.
	eo	Evaluation options.

Returns

1 if the calculation was successful.

Reimplemented from MathFunction.

string UserFunction::formula

(

)

const

Returns the external representation of the formula.

string UserFunction::internalFormula

(

)

const

Returns the internal representation of the formula.

void UserFunction::setFormula	(	string	new_formula,
		int	argc_ = -1,
		int	max_argc_ = 0
	)

Sets the formula of the mathematical function.

Parameters

new_formula	Formula/expression.
arc_	Minimum number of arguments or -1 to read from formula.
max_argc_	Maximum number of arguments (ignored if argc_ < 0)

void UserFunction::setSubfunction	(	size_t	index,
		string	subfunction
	)

Sets the formula for a subfunction.

Parameters

index	Index (starting at 1).
subfunction	Formula/expression.

int UserFunction::subtype ( ) const

virtual

Returns the subtype of the mathematical function, corresponding to which subsubclass the object belongs to.

Returns

FunctionSubtype.

Reimplemented from MathFunction.

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

• libqalculate/Function.h