Documentation of objfletwell
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ObjVal = objfletwell(Chrom, P1, P2)
OBJective function after FLETcher and PoWELL
This function implements the function after Fletcher and Powell
and a discretization of this objective function. The function
after Fletcher and Powell is highly multimodal and a
representative of nonlinear parameter estimation.
For the computation of this objective function two random matrices
A, B and a random vector alpha are used. Therefore the function is
not symmetric and the extrema are randomly distributed over the
search space. The random values of A, B and alpha are retrieved
by the private function getFletwellData.
This function was first introduced by Fletcher and Powell in:
Fletcher, R. and Powell, M.J.D., A rapidly convergent descent
method for minimization. Computer Journal, 6:163-168, 1963.
In connection with Evolution Strategies the function was used in:
Schwefel, H.-P., Numerische Optimierung von Computer-Modellen
mittels der Evolutionsstrategie, volume 26 of Interdisciplinary
Systems Research. Basel: Birkhaeuser, 1977, pp. 327-328.
Baeck, T., Evolutionary Algorithms in Theory and Practice.
New York-Oxford: Oxford University Press, 1996, pp. 143-144.
Syntax: ObjVal = objfletwell(Chrom, P1, P2)
Chrom - Matrix containing the chromosomes of the current
population. Each row corresponds to one individual's
If Chrom == [NaN xxx] or
Chrom == [NaN xxx yyy],
then special values will be returned, see Output parameters
xxx == 1 (or ) return boundaries
xxx == 2 return title
yyy == 0 return title of continuous variant
yyy == 1 return title of discrete variant
xxx == 3 return value of global minimum
P1 - (Optional) Number indicating which variant is used,
if Chrom is not NaN or .
P1 = 1 use discrete version
P1 = 0 use continuous version
If P1 is omitted or P1 =  the discrete version
is used (P1 = 1).
P2 - Additional parameter
ObjVal - Column vector containing the objective values of the
individuals in the current population.
if called with
Chrom == [NaN xxx] or Chrom == [NaN xxx yyy],
then ObjVal contains
xxx == 1 (or ), matrix with the boundaries of
xxx == 2, text with the title of the function
yyy omitted: title of continuous variant
yyy = 0 title of continuous variant
yyy = 1 title of discrete variant
xxx == 3, value of global minimum
% continuous variant of the function after Fletcher and Powell
% discrete variant of the function after Fletcher and Powell
>> objfletwell(Chrom, 1)
Author: Hartmut Pohlheim
History: 08.11.99 file created
This document is part of version 3.8
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,