T M V A G Aexample 2

This executable gives an example of a very simple use of the genetic algorithm of TMVA.

  • Project : TMVA - a Root-integrated toolkit for multivariate data analysis
  • Package : TMVA
  • Executable: TMVAGAexample

Author: Andreas Hoecker
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Thursday, June 17, 2021 at 06:05 PM.

In [1]:
%%cpp -d
#include <iostream> // Stream declarations
#include <vector>

#include "TMVA/GeneticAlgorithm.h"
#include "TMVA/GeneticFitter.h"
#include "TMVA/IFitterTarget.h"

using namespace std;

namespace TMVA {


class MyFitness : public IFitterTarget {
    public:
       MyFitness() : IFitterTarget() {
       }

       // the fitness-function goes here
       // the factors are optimized such that the return-value of this function is minimized
       // take care!! the fitness-function must never fail, .. means: you have to prevent
       // the function from reaching undefined values (such as x=0 for 1/x or so)
       //
       // HINT: to use INTEGER variables, it is sufficient to cast the "factor" in the fitness-function
       // to (int). In this case the variable-range has to be chosen +1 ( to get 0..5, take Interval(0,6) )
       // since the introduction of "Interval" ranges can be defined with a third parameter
       // which gives the number of bins within the interval. With that technique discrete values
       // can be achieved easier. The random selection out of this discrete numbers is completely uniform.
       //
       Double_t EstimatorFunction( std::vector<Double_t> & factors ){
           //return (10.- (int)factors.at(0) *factors.at(1) + (int)factors.at(2));
           return (10.- factors.at(0) *factors.at(1) + factors.at(2));

           //return 100.- (10 + factors.at(1)) *factors.at(2)* TMath::Abs( TMath::Sin(factors.at(0)) );
       }
};












} // namespace TMVA

A helper function is created:

In [2]:
%%cpp -d
void exampleGA(){
        std::cout << "\nEXAMPLE" << std::endl;
        // define all the parameters by their minimum and maximum value
        // in this example 3 parameters are defined.
        vector<Interval*> ranges;
        ranges.push_back( new Interval(0,15,30) );
        ranges.push_back( new Interval(0,13) );
        ranges.push_back( new Interval(0,5,3) );

        for( std::vector<Interval*>::iterator it = ranges.begin(); it != ranges.end(); it++ ){
           std::cout << " range: " << (*it)->GetMin() << "   " << (*it)->GetMax() << std::endl;
        }

        IFitterTarget* myFitness = new MyFitness();

        // prepare the genetic algorithm with an initial population size of 20
        // mind: big population sizes will help in searching the domain space of the solution
        // but you have to weight this out to the number of generations
        // the extreme case of 1 generation and populationsize n is equal to
        // a Monte Carlo calculation with n tries

        const TString name( "exampleGA" );
        const TString opts( "PopSize=100:Steps=30" );

        GeneticFitter mg( *myFitness, name, ranges, opts);
       // mg.SetParameters( 4, 30, 200, 10,5, 0.95, 0.001 );

        std::vector<Double_t> result;
        Double_t estimator = mg.Run(result);

         int n = 0;
         for( std::vector<Double_t>::iterator it = result.begin(); it<result.end(); it++ ){
             std::cout << "FACTOR " << n << " : " << (*it) << std::endl;
             n++;
         }

}
input_line_42:5:16: error: use of undeclared identifier 'Interval'
        vector<Interval*> ranges;
               ^
input_line_42:5:25: error: expected expression
        vector<Interval*> ranges;
                        ^
input_line_42:6:9: error: use of undeclared identifier 'ranges'
        ranges.push_back( new Interval(0,15,30) );
        ^
input_line_42:6:31: error: unknown type name 'Interval'
        ranges.push_back( new Interval(0,15,30) );
                              ^
input_line_42:7:9: error: use of undeclared identifier 'ranges'
        ranges.push_back( new Interval(0,13) );
        ^
input_line_42:7:31: error: unknown type name 'Interval'
        ranges.push_back( new Interval(0,13) );
                              ^
input_line_42:8:9: error: use of undeclared identifier 'ranges'
        ranges.push_back( new Interval(0,5,3) );
        ^
input_line_42:8:31: error: unknown type name 'Interval'
        ranges.push_back( new Interval(0,5,3) );
                              ^
input_line_42:10:26: error: use of undeclared identifier 'Interval'
        for( std::vector<Interval*>::iterator it = ranges.begin(); it != ranges.end(); it++ ){
                         ^
input_line_42:10:35: error: expected expression
        for( std::vector<Interval*>::iterator it = ranges.begin(); it != ranges.end(); it++ ){
                                  ^
input_line_42:10:38: error: use of class template '::iterator' requires template arguments
        for( std::vector<Interval*>::iterator it = ranges.begin(); it != ranges.end(); it++ ){
                                     ^
/usr/include/c++/9/bits/stl_iterator_base_types.h:118:12: note: template is declared here
    struct iterator
           ^
input_line_42:10:52: error: use of undeclared identifier 'ranges'
        for( std::vector<Interval*>::iterator it = ranges.begin(); it != ranges.end(); it++ ){
                                                   ^
input_line_42:10:74: error: use of undeclared identifier 'ranges'
        for( std::vector<Interval*>::iterator it = ranges.begin(); it != ranges.end(); it++ ){
                                                                         ^
input_line_42:14:9: error: unknown type name 'IFitterTarget'
        IFitterTarget* myFitness = new MyFitness();
        ^
input_line_42:14:40: error: unknown type name 'MyFitness'
        IFitterTarget* myFitness = new MyFitness();
                                       ^
input_line_42:25:9: error: unknown type name 'GeneticFitter'
        GeneticFitter mg( *myFitness, name, ranges, opts);
        ^
input_line_42:25:45: error: use of undeclared identifier 'ranges'
        GeneticFitter mg( *myFitness, name, ranges, opts);
                                            ^
In [3]:
cout << "Start Test TMVAGAexample" << endl
     << "========================" << endl
     << endl;

TMVA::exampleGA();
input_line_43:6:7: error: no member named 'exampleGA' in namespace 'TMVA'
TMVA::exampleGA();
~~~~~~^