Documentation of compete

Global Index (all files) (short | long) | Local contents | Local Index (files in subdir) (short | long)

Function Synopsis

[NewChrom, NewObjV, SubPop, CompQuality, TestVars] = compete(Chrom, SubPop, CompQuality, CompOpt, ObjV, FitnV);

Help text

 COMPETition between subpopulations

 This function performs competition between subpopulations.
 The division of the individuals to the subpopulations can be 
 controlled by one parameter - the division pressure. The 
 effect of this parameter is identical to selection pressure
 (even the same functions are used for calculation). Instead 
 of using individuals here we use subpopulations.
 The selection of the individuals for transfer to other 
 (better) subpopulations can be chosen between:
  - uniform at random selection
  - fitness-based selection
 For fitness-based competition (worst individuals are deleted)
 the fitness values/ranking of the population (FitnV) is needed.
 If omitted or empty single objective scaling using the first
 column of the objective values (ObjV) is assumed.
 If the objective values of the population (ObjV) are input
 parameter and ObjV is output parameter the objective values
 are copied, according to the flowing of individuals, saving
 the recomputation of the objective values for the whole popu-
 The function can handle multiple objective values per individual. 

 Syntax:  [NewChrom, NewObjV, SUBPOP, CompQuality] = compete(Chrom, SUBPOP, CompQuality, CompOpt, ObjV, FitnV)

 Input parameters:
    Chrom     - Matrix containing the individuals of the current
                population. Each row corresponds to one individual.
    SubPop    - Vector/scalar containing number of individuals per
                subpopulation/number of subpopulations
                if omitted or NaN, 1 subpopulation is assumed
    CompQuality - Vector containing the competition quality of each
                  subpopulation (output parameter of this function)
                if omitted, NaN or empty, CompQuality is calculated
                equivalent to the size of each subpopulation
    CompOpt   - (optional) Vector containing competition paremeters
                CompOpt(1): CompRate - Rate of individuals to be deleted/
                            included per subpopulation (% of subpopulation)
                            if omitted or NaN, 0.2 (20%) is assumed
                CompOpt(2): Select - number indicating the selection method
                            of deleting individuals
                            0 - uniform selection
                            1 - fitness-based selection (worst individuals are deleted)
                            if omitted or NaN, 1 is assumed
                CompOpt(3): CompMin - number indicating the minimal number of
                            individuals in a subpopulation
                            if omitted or NaN, 5 is assumed
                CompOpt(4): DivisionPressure (analog to selective pressure)
                            can be given in the range: 1 - (NumSubPop-2)
                            1: no division pressure (not really useful)
                            2: the best subpop receives twice as many individuals 
                               as the mean of all subpops
                            max value (for instance 4, when using 6 subpops): the
                                best subpop gets 4 times as many individuals ...
                                (this means nearly 50% of the individuals)
                            (maximal 2 for linear division)
                            if omitted or NaN, 2 is assumed
                CompOpt(5): for test purpose only
                            NaN: automatically selected 
                                (DivisionPressure <=2: linear division, 
                                 else non-linear) 
                            1: lin. division function
                            2: nonlin. division function
    ObjV      - Column vector or matrix containing the objective values
                of the individuals in the current population,
                if Rank is omitted, first column is used for
                fitness-based competition, saves recalculation
                of objective values for population
    FitnV     - (optional) Column vector containing the fitness
                values of the individuals
                in the current population, best individual has
                highest value,
                if omitted or empty, single objective scaling
                using first column of ObjV is assumed

 Output parameters:
    NewChrom  - Matrix containing the individuals of the current
                population after competition.
    NewObjV   - (optional) Column vector containing the objective
                values of the individuals of the current generation
                after competition.
    SubPop    - (optional) Vector/scalar containing number of indi-
                viduals per subpopulation/number of subpopulations
                after competition

 See also: geamain2, migrate, compdiv

Cross-Reference Information

This function calls This function is called by
GEATbx: Main page  Tutorial  Algorithms  M-functions  Parameter/Options  Example functions 

This document is part of version 3.8 of the GEATbx: Genetic and Evolutionary Algorithm Toolbox for use with Matlab -
The Genetic and Evolutionary Algorithm Toolbox is not public domain.
© 1994-2006 Hartmut Pohlheim, All Rights Reserved, (