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FunctionAbstractions.hpp
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//===-- rosa/agent/FunctionAbstractions.hpp ---------------------*- C++ -*-===//
//
// The RoSA Framework
//
//===----------------------------------------------------------------------===//
///
/// \file rosa/agent/FunctionAbstractions.hpp
///
/// \author Benedikt Tutzer (benedikt.tutzer@tuwien.ac.at)
///
/// \date 2019
///
/// \brief Definition of *FunctionAbstractions* *functionality*.
///
//===----------------------------------------------------------------------===//
#ifndef ROSA_AGENT_FUNCTIONABSTRACTIONS_HPP
#define ROSA_AGENT_FUNCTIONABSTRACTIONS_HPP
#include "rosa/agent/Abstraction.hpp"
#include "rosa/agent/Functionality.h"
#include "rosa/support/debug.hpp"
#include <algorithm>
#include <cmath>
#include <memory>
#include <vector>
namespace rosa {
namespace agent {
//@benedikt: check if your partialfunctions can take infinity as
// argument
/// Implements \c rosa::agent::Abstraction as a linear function,
/// y = Coefficient * X + Intercept.
///
/// \note This implementation is supposed to be used to represent a linear
/// function from an arithmetic domain to an arithmetic range. This is enforced
/// statically.
///
/// \tparam D type of the functions domain
/// \tparam R type of the functions range
template <typename D, typename R>
class LinearFunction : public Abstraction<D, R> {
// Make sure the actual type arguments are matching our expectations.
STATIC_ASSERT((std::is_arithmetic<D>::value),
"LinearFunction not arithmetic T");
STATIC_ASSERT((std::is_arithmetic<R>::value),
"LinearFunction not to arithmetic");
protected:
/// The Intercept of the linear function
const D Intercept;
/// The Coefficient of the linear function
const D Coefficient;
public:
/// Creates an instance.
///
/// \param Intercept the intercept of the linear function
/// \param Coefficient the coefficient of the linear function
LinearFunction(D Intercept, D Coefficient) noexcept
: Abstraction<D, R>(Intercept), Intercept(Intercept),
Coefficient(Coefficient) {}
/// Creates an instance given the two points on a linear function.
///
/// \param x1 The x-value of the first point
/// \param y1 The x-value of the first point
/// \param x2 The y-value of the second point
/// \param y2 The y-value of the second point
LinearFunction(D x1, R y1, D x2, R y2) noexcept
: LinearFunction<D, R>(y1 - x1 * (y1 - y2) / (x1 - x2),
(y1 - y2) / (x1 - x2)) {}
/// Creates an instance given the two points on a linear function.
///
/// \param p1 The coordinates of the first point
/// \param p2 The coordinates of the second point
LinearFunction(std::pair<D, R> p1, std::pair<D, R> p2) noexcept
: LinearFunction<D, R>(p1.first, p1.second, p2.first, p2.second) {}
/// Destroys \p this object.
~LinearFunction(void) = default;
/// Checks wether the Abstraction evaluates to default at the given position
/// As LinearFunctions can be evaluated everythwere, this is always false
///
/// \param V the value at which to check if the function falls back to it's
/// default value.
///
/// \return false
bool isDefaultAt(const D &V) const noexcept override {
(void)V;
return false;
}
/// Getter for member variable Intercept
///
/// \return Intercept
D getIntercept() const { return Intercept; }
/// Setter for member variable Intercept
///
/// \param Intercept the new Intercept
void setIntercept(const D &Intercept) { this->Intercept = Intercept; }
/// Getter for member variable Coefficient
///
/// \return Coefficient
D getCoefficient() const { return Coefficient; }
/// Setter for member variable Coefficient
///
/// \param Coefficient the new Intercept
void setCoefficient(const D &Coefficient) { this->Coefficient = Coefficient; }
/// Set Intercept and Coefficient from two points on the linear function
///
/// \param x1 The x-value of the first point
/// \param y1 The x-value of the first point
/// \param x2 The y-value of the second point
/// \param y2 The y-value of the second point
void setFromPoints(D x1, R y1, D x2, R y2) {
Coefficient = (y1 - y2) / (x1 - x2);
Intercept = y1 - Coefficient * x1;
}
/// Set Intercept and Coefficient from two points on the linear function
///
/// \param p1 The coordinates of the first point
/// \param p2 The coordinates of the second point
inline void setFromPoints(std::pair<D, R> p1, std::pair<D, R> p2) {
setFromPoints(p1.first, p1.second, p2.first, p2.second);
}
/// Evaluates the linear function
///
/// \param X the value at which to evaluate the function
///
/// \return Coefficient*X + Intercept
virtual R operator()(const D &X) const noexcept override {
return Intercept + X * Coefficient;
}
};
/// Implements \c rosa::agent::Abstraction as a sine function,
/// y = Amplitude * sin(Frequency * X + Phase) + Average.
///
/// \note This implementation is supposed to be used to represent a sine
/// function from an arithmetic domain to an arithmetic range. This is enforced
/// statically.
///
/// \tparam D type of the functions domain
/// \tparam R type of the functions range
template <typename D, typename R>
class SineFunction : public Abstraction<D, R> {
// Make sure the actual type arguments are matching our expectations.
STATIC_ASSERT((std::is_arithmetic<D>::value),
"SineFunction not arithmetic T");
STATIC_ASSERT((std::is_arithmetic<R>::value),
"SineFunction not to arithmetic");
protected:
/// The frequency of the sine wave
const D Frequency;
/// The Ampiltude of the sine wave
const D Amplitude;
/// The Phase-shift of the sine wave
const D Phase;
/// The y-shift of the sine wave
const D Average;
public:
/// Creates an instance.
///
/// \param Frequency the frequency of the sine wave
/// \param Amplitude the amplitude of the sine wave
/// \param Phase the phase of the sine wave
/// \param Average the average of the sine wave
SineFunction(D Frequency, D Amplitude, D Phase, D Average) noexcept
: Abstraction<D, R>(Average), Frequency(Frequency), Amplitude(Amplitude),
Phase(Phase), Average(Average) {}
/// Destroys \p this object.
~SineFunction(void) = default;
/// Checks wether the Abstraction evaluates to default at the given position
/// As SineFunctions can be evaluated everythwere, this is always false
///
/// \param V the value at which to check if the function falls back to it's
/// default value.
///
/// \return false
bool isDefaultAt(const D &V) const noexcept override {
(void)V;
return false;
}
/// Evaluates the sine function
///
/// \param X the value at which to evaluate the function
/// \return the value of the sine-function at X
virtual R operator()(const D &X) const noexcept override {
return Amplitude * sin(Frequency * X + Phase) + Average;
}
};
enum StepDirection { StepUp, StepDown };
/// Implements \c rosa::agent::PartialFunction as a step function from 0 to 1
/// with a ramp in between
///
/// \tparam D type of the functions domain
/// \tparam R type of the functions range
template <typename D, typename R>
class StepFunction : public Abstraction<D, R> {
// Make sure the actual type arguments are matching our expectations.
STATIC_ASSERT((std::is_arithmetic<D>::value), "abstracting not arithmetic");
STATIC_ASSERT((std::is_arithmetic<R>::value),
"abstracting not to arithmetic");
private:
D Coefficient;
D RightLimit;
StepDirection Direction;
public:
/// Creates an instance by Initializing the underlying \c Abstraction.
///
/// \param Coefficient Coefficient of the ramp
/// \param Direction wether to step up or down
///
/// \pre Coefficient > 0
StepFunction(D Coefficient, StepDirection Direction = StepUp)
: Abstraction<D, R>(0), Coefficient(Coefficient),
RightLimit(1.0f / Coefficient), Direction(Direction) {
ASSERT(Coefficient > 0);
}
/// Destroys \p this object.
~StepFunction(void) = default;
/// Setter for Coefficient
///
/// \param Coefficient the new Coefficient
void setCoefficient(const D &Coefficient) {
ASSERT(Coefficient > 0);
this->Coefficient = Coefficient;
this->RightLimit = 1 / Coefficient;
}
/// Setter for RightLimit
///
/// \param _RightLimit the new RightLimit
void setRightLimit(const D &_RightLimit) {
ASSERT(_RightLimit > 0);
this->RightLimit = _RightLimit;
this->Coefficient = 1 / _RightLimit;
}
/// Checks wether the Abstraction evaluates to default at the given position
///
/// \param V the value at which to check if the function falls back to it's
/// default value.
///
/// \return false if the is negative, true otherwise
bool isDefaultAt(const D &V) const noexcept override { return V > 0; }
/// Executes the Abstraction
///
/// \param V value to abstract
///
/// \return the abstracted value
R operator()(const D &V) const noexcept override {
R ret = 0;
if (V <= 0)
ret = 0;
else if (V >= RightLimit)
ret = 1;
else
ret = V * Coefficient;
return Direction == StepDirection::StepUp ? ret : 1 - ret;
}
};
/// Implements \c rosa::agent::Abstraction as a partial function from a domain
/// to a range.
///
/// \note This implementation is supposed to be used to represent a partial
/// function from an arithmetic domain to an arithmetic range. This is enforced
/// statically.
///
/// A partial function is defined as a list of abstractions, where each
/// abstraction is associated a range in which it is defined. These ranges must
/// be mutually exclusive.
///
/// \tparam D type of the functions domain
/// \tparam R type of the functions range
template <typename D, typename R>
class PartialFunction : public Abstraction<D, R> {
// Make sure the actual type arguments are matching our expectations.
STATIC_ASSERT((std::is_arithmetic<D>::value), "abstracting not arithmetic");
STATIC_ASSERT((std::is_arithmetic<R>::value),
"abstracting not to arithmetic");
private:
/// A \c rosa::agent::RangeAbstraction RA is used to represent the association
/// from ranges to Abstractions.
/// This returns the Abstraction that is defined for any given value, or
/// a default Abstraction if no Abstraction is defined for that value.
RangeAbstraction<D, std::shared_ptr<Abstraction<D, R>>> RA;
public:
/// Creates an instance by Initializing the underlying \c Abstraction.
///
/// \param Map the mapping to do abstraction according to
/// \param Default abstraction to abstract to by default
///
/// \pre Each key defines a valid range such that `first <= second` and
/// there are no overlapping ranges defined by the keys.
PartialFunction(
const std::map<std::pair<D, D>, std::shared_ptr<Abstraction<D, R>>> &Map,
const R Default)
: Abstraction<D, R>(Default),
RA(Map,
std::shared_ptr<Abstraction<D, R>>(new Abstraction<D, R>(Default))) {
}
/// Destroys \p this object.
~PartialFunction(void) = default;
/// Checks wether the Abstraction evaluates to default at the given position
///
/// \param V the value at which to check if the function falls back to it's
/// default value.
///
/// \return false if the value falls into a defined range and the Abstraction
/// defined for that range does not fall back to it's default value.
bool isDefaultAt(const D &V) const noexcept override {
return RA.isDefaultAt(V) ? true : RA(V)->isDefaultAt(V);
}
/// Searches for an Abstraction for the given value and executes it for that
/// value, if such an Abstraction is found. The default Abstraction is
/// evaluated otherwise.
///
/// \param V value to abstract
///
/// \return the abstracted value based on the set mapping
R operator()(const D &V) const noexcept override {
return RA(V)->operator()(V);
}
};
} // End namespace agent
} // End namespace rosa
#endif // ROSA_AGENT_FUNCTIONABSTRACTIONS_HPP

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