========================================================================
PISA  (www.tik.ee.ethz.ch/pisa/)
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Computer Engineering (TIK)
ETH Zurich	 
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SIBEA - Simple Indicator Based Evolutionary Algorithm

Implementation in Java for the selector side.

Documentation
  
author: Johannes Bader, johannes.bader@tik.ee.ethz.ch
last change: 3.11.2008
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The Optimizer
=============

SIBEA is an multiobjective evolutionary algorithm that calculates fitness
values based on the SIBEA rvolume contribution. Thereby,
no particular diversity preservation techniques such as fitness sharing,
clustering, etc. is necessary. For biobjective problems, SIBEA uses dynamic programming in
the environmental selection step to obtain the obtimal subset. For higher dimensions, a greedy
approach is used instead.

@InProceedings{	  bz2007c,
	author={D. Brockhoff and E. Zitzler},
	title={{Improving SIBEA rvolume-based Multiobjective Evolutionary Algorithms by Using Objective Reduction Methods}},
	booktitle={Congress on Evolutionary Computation (CEC 2007)},
	year={2007},
	pages={2086--2093},
	publisher={IEEE Press},
	location={Singapore},
	supplement={https://sop.tik.ee.ethz.ch/download/supplementary/objectiveReduction/}
}

The Parameters
==============

SIBEA uses the following values for the common parameters.
These parameters are specified in 'PISA_cfg'.

alpha    (population size)
mu       (number of parent individuals)
lambda   (number of offspring individuals)
dim      (number of objectives)



SIBEA takes two local parameter which is given in a parameter
file. The name of this parameter file is passed to SIBEA  as command
line argument. (See 'SIBEA _param.txt' for an example.)

seed         (seed for the random number generator)
bound        (upper bound defining the reference point as r = (bound, ..., bound) )


Usage
=====

Start SIBEA  with the following arguments:

SIBEA  paramfile filenamebase poll

paramfile: specifies the name of the file containing the local
parameters (e.g. SIBEA_param.txt)

filenamebase: specifies the name (and optionally the directory) of the
communication files. The filenames of the communication files and the
configuration file are built by appending 'sta', 'var', 'sel','ini',
'arc' and 'cfg' to the filenamebase. This gives the following names for
the 'PISA_' filenamebase:

PISA_cfg - configuration file
PISA_ini - initial population
PISA_sel - individuals selected for variation (PISA_
PISA_var - variated individuals (offspring)
PISA_arc - individuals in the archive


Caution: the filenamebase must be consistent with the name of
the configuration file and the filenamebase specified for the SIBEA 
module.

poll: gives the value for the polling time in seconds (e.g. 0.5). This
      polling time must be larger than 0.01 seconds.




Limitations
===========

None limitations are known so far.



Stopping and Resetting
======================

The behaviour in state 5 and 9 is not determined by the interface but
by each variator module specifically. SIBEA  behaves as follows:

state 5 (= variator terminated): set state to 6 (terminate as well).
state 9 (= variator resetted): set state to 10 (reset as well).