class Rivet::MendelMin

Rivet::MendelMin #

A genetic algorithm functional minimizer. More…

#include <MendelMin.hh>

Public Types ##

Public Functions ##

Public Attributes ##

Detailed Description ##

class Rivet::MendelMin;

A genetic algorithm functional minimizer.

MendelMin implements a home brewed genetic algorithm for finding the minimum of a function defined on a unit hypercube returning a non-negative real number (eg. a Chi-squared value).

Public Types Documentation ##

using Params ##

using Rivet::MendelMin::Params =  std::valarray<double>;

Typedef for a valaray of parameters to the function to be minimised.

using FuncT ##

using Rivet::MendelMin::FuncT =  std::function<double(const Params&, const Params&)>;

Typedef for the function to be minimised.

using FuncNoFixedT ##

using Rivet::MendelMin::FuncNoFixedT =  std::function<double(const Params&)>;

Typedef for the function to be minimised.

Public Functions Documentation ##

function MendelMin ##

inline MendelMin(
    const FuncT & fin,
    unsigned int ndim,
    const Params & fixpar,
    unsigned int npop =20,
    unsigned int ngen =20,
    double margin =0.1
)

Constructor with fixed parameters

Mandatory arguments: the function, fin, to be minimised; the dimension, ndim, of the unit hypercube for which fin is defined; a set of fixed parameters not to be optimised.

Optional arguments are: the number, npop, of individuals in the population; and margin which determines how much randomness is involved when an individual is evolved twowards the fittest individual.

function MendelMin ##

inline MendelMin(
    const FuncNoFixedT & fin,
    unsigned int ndim,
    unsigned int npop =20,
    unsigned int ngen =20,
    double margin =0.1
)

Constructor without fixed parameters

Mandatory arguments: the function, fin, to be minimised; the dimension, ndim, of the unit hypercube for which fin is defined.

Optional arguments are: the number, npop, of individuals in the population; and margin which determines how much randomness is involved when an individual is evolved twowards the fittest individual.

function guess ##

inline void guess(
    const Params & p
)

Supply a best guess for the fittest parameter point to help things along.

function evolve ##

inline double evolve(
    unsigned int NGen
)

Evolve the population a given number of generations and return the best fit value.

function fittest ##

inline Params fittest() const

Return the fittest parameter point found.

function fit ##

inline double fit() const

Return the fittest value found.

function rnd ##

inline double rnd() const

Simple wrapper around the random number generator.

function rndParams ##

inline Params rndParams() const

Return a random parameter point in the unit hypercube.

function limit01 ##

inline void limit01(
    Params & p
) const

Limit a parameter point to inside the unit hypercube.

function move ##

inline void move(
    Params & bad,
    const Params & better
) const

Move a bad parameter point towards a better one. The new point is picked randomly within the generalized hypercube where bad and better are at diagonally opposite corners, enlarged by a fraction _margin.

function f ##

inline double f(
    const Params & p
) const

Simple wrapper around the function to be minimised.

function minmax ##

inline std::pair< double, double > minmax()

Return: the best and worst fitness values.

Calculate the fitness values of all individuals and put the fittest one first.

Public Attributes Documentation ##

variable showTrace ##

bool showTrace;

Set true to get a verbose record of the evolution.

Updated on 2022-08-07 at 20:17:17 +0100