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ValueGenerator< T > Class Template Reference

#include <valuegen.h>

Inheritance diagram for ValueGenerator< T >:

[legend]Collaboration diagram for ValueGenerator< T >:

[legend]List of all members.

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Detailed Description

template<class T = double>
class ValueGenerator< T >

This heads a class hierarchy of objects which primarily contain a variable of the given type, but which also contain operations for automatically generating a new value from a given distribution or by some other means.

Semantics for a value "a" of this type and a value "b" of the numeric type "T" which it contains:

    ValueGenerator<T>  a;
    T b;
    T* c;
    ValueGenerator<T>* d;

    a = b;           // Assign the value b to a
    b = a.value();   // Assign the value of a to b
                     // (can omit .value() if conversion operator defined)
    a.next();        // Choose a new value for a; returns false if unsuccessful
    a.reset();       // Reset a to its initial value, if any
    c = a.valueptr();// Returns address of data in a
    c = a.genptr();  // Returns address of a
    d = a.clone();   // d points to an identical but independent copy of a
                     // (i.e., d may outlive a.  This helps support
		     // polymorphism, since a may be of a subtype of d, yet
		     // the duplicate is of the subtype, not d's type.
  

Various derived types are used to support different distributions by reimplementing "next()" and "reset()"; their interface should differ only by their constructors and not by their usage.

The operator relink() is supported for the rare instances when one might wish to change a stored external value pointer to point to a different location. If an internal storage location is actually being used, the operation has no effect.

This base class is a basic version that acts just like an ordinary variable or reference.

Definition at line 96 of file valuegen.h.

Public Methods
	ValueGenerator (T value=T())
	Constructor for an internally-allocated variable.
	ValueGenerator (T *value)
	Constructor for a reference to an external value.
	ValueGenerator (StringArgs &args)
virtual string	stringrep () const
	Returns the value as a scalar.
T	operator * () const
	Returns the current underlying value.
T	value () const
	Returns the current underlying value.
T *	valueptr () const
	Returns a pointer to the underlying value; use with caution.
Operations that may be overridden by derived classes
virtual void	relink (T *ptr)
virtual bool	next ()
	Advance to the next state (whatever that means for this object).
virtual void	reset ()
	Reset to the starting state.
virtual ValueGenerator< T > *	clone () const
	Constructs an identical copy of self and returns it.

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Member Function Documentation

template<class T = double> virtual string ValueGenerator< T >::stringrep (    )  const [inline, virtual]

Returns the value as a scalar. Derived classes will usually want to provide a more specific representation, namely what the StringArgs constructor will accept for that class. At present it cannot be guaranteed that the value returned is actually what was used to create the object; perhaps the StringArgs passed to the constructor should be saved instead. If so, the StringArgs constructor above would have to be changed to include a string specifying the ValueGenerator type. Reimplemented in ValueGenerator_Random< T, RandomGen >, ValueGenerator_Correlate< T, RandomGen, crop >, ValueGenerator_Opposite< T >, ValueGenerator_Increment< T >, and ValueGenerator_Expression< T >. Definition at line 120 of file valuegen.h. References String::stringrep(), and ValueGenerator< T >::value(). Referenced by Retinal_Object::vargen_stringrep().

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

• valuegen.h

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