O_SESSAME::Functor Class Reference
[Integration Library, Environment Toolkit]

#include <Functor.h>

Inheritance diagram for O_SESSAME::Functor:

[legend]List of all members.

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Detailed Description

Abstract class to hold the pointer to an force calculating functor.

A Function Object, or Functor (the two terms are synonymous) is simply any object that can be called as if it is a function. It is used to define a call-back function that evaluates any algorithm that takes the defined inputs and returns a vector of values. Examples of usage include evaluating a disturbance force or torque given the current time, orbit state, and attitude state. The returned vector will then be the 3 forces (or torques).

Examples:

The simplest functor is a placeholder that can be set to just return a vector of zeros:

Vector NullFunctor(const ssfTime& _pSSFTime, const OrbitState& _pOrbitState, const AttitudeState& _pAttitudeState)
{
    return Vector(3);
}

This isn't very useful, but may be necessary for filling out a parameter list such as for

See also:

Integrator that requests a Functor call-back function. The Functor object is created as follows:

SpecificFunctor AttitudeForcesFunctor(&NullFunctor);

SpecificFunctor is used since it is only a function that was used, and not a member function of a class. For that case, an ObjectFunctor is required which stores the type (or class) of the function as well as the pointer to the function itself.

An ObjectFunctor may be assigned from an Environment object (pEarthEnv) where the function is GetForces:

ObjectFunctor<Environment> OrbitForcesFunctor(pEarthEnv, &Environment::GetForces);

To review, we are creating an ObjectFunctor that will hold a call-back function to the Environment class (hence the template argument ). The function, OrbitForcesFunctor, needs a pointer to the instance of the class we are using (pEarthEnv), and the reference to the function (&Environment::GetForces). The & is required to specify that it is a reference, and the Environment:: defines the scope of the function GetForces. It is also important to note that the GetForces function conforms to the ObjectFunctor interface. (

See also:

Environment::GetForces).

Todo:

make Functors for variety of function types

Definition at line 63 of file Functor.h.

Public Member Functions
virtual Vector	Call (const ssfTime &, const OrbitState &, const AttitudeState &) const=0

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Member Function Documentation

virtual Vector O_SESSAME::Functor::Call (  const ssfTime &  , const OrbitState &  , const AttitudeState &  )  const [pure virtual]

Implemented in O_SESSAME::SpecificFunctor, O_SESSAME::ObjectFunctor< TClass >, and O_SESSAME::ObjectFunctor< Environment >.

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