Documentation of seltrunc

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Function Synopsis

NewChromIx = seltrunc(FitnV, Nsel, Dummy);

Help text

 SELection by TRUNCation

 This function performs SELection by TRUNCation.

 Syntax:  NewChromIx = seltrunc(FitnV, Nsel)

 Input parameters:
    FitnV     - Column vector containing the fitness values of the
                individuals in the population.
    Nsel      - Number of individuals to be selected

 Output parameters:
    NewChromIx- Column vector containing the indexes of the selected
                individuals relative to the original population, shuffeld.
                The new population, ready for mating, can be obtained
                by calculating OldChrom(NewChromIx,:).

 For the truncation threshold the inverse of the selection
 pressure is used (Trunc = 1/SP).
 1/SP is computed from FitnV by mean(FitnV)/max(FitnV)

 See also: selection, selsus, selrws, seltour, sellocal

 Example:
    % define fitness vector
       FitnV = [.1; .9; 1.6; 2.0; 0.4; 1.3; 1.7; 0.7; 0.2];
    % selects 6 indices from FitnV, Trunc = 0.5;
       NewChromIx = seltrunc(FitnV, 6);
    % possible result
       NewChromIx = [3; 4; 2; 4; 6; 7];
    % Get selected individuals from population Chrom
       SelChrom = Chrom(NewChromIx, :)

Cross-Reference Information

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

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