AliasUnit Class Reference

An unit with relation to another unit. More...

`#include <Unit.h>`

Inheritance diagram for AliasUnit:

## Public Member Functions

| AliasUnit (string cat_, string name_, string plural_, string singular_, string title_, Unit *alias, string relation="1", int exp=1, string inverse="", bool is_local=true, bool is_builtin=false, bool is_active=true)
| AliasUnit (const AliasUnit *unit)
virtual ExpressionItem * | copy () const
virtual void | set (const ExpressionItem *item)
virtual Unit * | baseUnit () const
virtual Unit * | firstBaseUnit () const
virtual void | setBaseUnit (Unit *alias)
virtual string | expression () const
virtual string | inverseExpression () const
virtual string | uncertainty (bool *is_relative=NULL) const
virtual void | setExpression (string relation)
virtual void | setInverseExpression (string inverse)
virtual void | setUncertainty (string standard_uncertainty, bool is_relative=false)
virtual MathStructure & | convertToFirstBaseUnit (MathStructure &mvalue, MathStructure &mexp) const
virtual MathStructure & | convertFromFirstBaseUnit (MathStructure &mvalue, MathStructure &mexp) const
virtual MathStructure & | convertToBaseUnit (MathStructure &mvalue, MathStructure &mexp) const
virtual MathStructure & | convertFromBaseUnit (MathStructure &mvalue, MathStructure &mexp) const
virtual MathStructure & | convertToBaseUnit (MathStructure &mvalue) const
virtual MathStructure & | convertFromBaseUnit (MathStructure &mvalue) const
virtual MathStructure | convertToBaseUnit () const
virtual MathStructure | convertFromBaseUnit () const
virtual int | baseExponent (int exp=1) const
virtual void | setExponent (int exp)
virtual int | firstBaseExponent () const
virtual int | mixWithBase () const
virtual int | mixWithBaseMinimum () const
virtual void | setMixWithBase (int combine_priority=1)
virtual void | setMixWithBaseMinimum (int combine_minimum)
virtual int | subtype () const
virtual bool | isChildOf (Unit *u) const
virtual bool | isParentOf (Unit *u) const
virtual bool | hasNonlinearExpression () const
virtual bool | hasNonlinearRelationTo (Unit *u) const
virtual bool | hasApproximateExpression (bool check_variables=false, bool ignore_high_precision_intervals=false) const
virtual bool | hasApproximateRelationTo (Unit *u, bool check_variables=false, bool ignore_high_precision_intervals=false) const
virtual bool | containsRelativeTo (Unit *u) const
virtual bool | hasNonlinearRelationToBase () const
virtual bool | hasApproximateRelationToBase (bool check_variables=false, bool ignore_high_precision_intervals=false) const
Public Member Functions inherited from Unit
| Unit (string cat_, string name_, string plural_="", string singular_="", string title_="", bool is_local=true, bool is_builtin=false, bool is_active=true)
| Unit (const Unit *unit)
bool | isSIUnit () const
void | setAsSIUnit ()
void | setSystem (string s_system)
const string & | system () const
bool | useWithPrefixesByDefault () const
void | setUseWithPrefixesByDefault (bool use_with_prefixes)
bool | isCurrency () const
const string & | countries () const
void | setCountries (string country_names)
virtual string | print (bool plural_, bool short_, 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 & | plural (bool return_singular_if_no_plural=true, 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 & | singular (bool return_abbreviation_if_no_singular=true, 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 & | abbreviation (bool return_singular_if_no_abbreviation=true, bool use_unicode=false, bool(*can_display_unicode_string_function)(const char *, void *)=NULL, void *can_display_unicode_string_arg=NULL) const
virtual bool | isUsedByOtherUnits () const
virtual int | type () const
bool | convert (Unit *u, MathStructure &mvalue, MathStructure &exp) const
bool | convert (Unit *u, MathStructure &mvalue) const
MathStructure | convert (Unit *u, bool *converted=NULL) 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 | svalue
string | sinverse
string | suncertainty
bool | b_relative_uncertainty
int | i_exp
int | i_mix
int | i_mix_min
Unit * | o_unit
Protected Attributes inherited from Unit
string | ssystem
string | scountries
bool | b_si
bool | b_use_with_prefixes
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

## Detailed Description

An unit with relation to another unit.

Alias units is defined in relation to another unit. For example, hour are defined as an alias unit that equals 60 minutes which in turn is defined in relation to seconds.

Alias units have an associated base unit, exponent and relation expression. For more complex relations an inverse relation can also be specified for conversion back from the base unit. The base unit must not necessarily be of the base unit class and it is recommended that an alias unit is defined in relation to the closest unit (ex. 1ft = 3 hands, 1 hand = 4 in, and 1 in = 0.0254 m).

The relation is usually just a number that tells how large quantity of the base unit is needed to get the alias unit (alias unit = base unit * relation). More complex units can specify the relation as a full-blown expression where '\x' is replaced by the quantity of the base unit and '\y' is the exponent. For example, Degrees Celsius has the relation "\x + 273.15" and the inverse relation "\x - 273.15" to the base unit Kelvin. For simple relations, the reversion is automatic and ought not be defined separately.

The precision property inherited from ExpressionItem defines the precision of the relation.

The exponent defines the exponential relation to the base unit, so that the alias unit equals the base unit raised to the exponent. For simple unit relations this gives: alias unit = relation * base unit^exponent.

Alias units normally have three different names defined for use in expressions - abbreviation (ex. "m"), singular ("meter") and plural ("meters").

## Member Function Documentation

## isChildOf()

virtual bool AliasUnit::isChildOf | ( | Unit * | u | ) | const

virtual

If specified unit is a base unit for this unit, directly or with other units in between. Equivalent to u->isParentOf(this).

Reimplemented from Unit.

## isParentOf()

virtual bool AliasUnit::isParentOf | ( | Unit * | u | ) | const

virtual

If this unit is a base unit for specified unit, directly or with other units in between. Equivalent to u->isChildOf(this).

Reimplemented from Unit.

## setExpression()

virtual void AliasUnit::setExpression | ( | string | relation | ) |

virtual

Sets the relation expression.

## setInverseExpression()

virtual void AliasUnit::setInverseExpression | ( | string | inverse | ) |

virtual

Sets the inverse relation expression.

## subtype()

virtual int AliasUnit::subtype | ( |  | ) | const

virtual

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

Returns
  UnitSubtype.

Reimplemented from Unit.

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

- libqalculate/Unit.h