view release on metacpan or  search on metacpan

lib/AI/ParticleSwarmOptimization/MCE.pm  view on Meta::CPAN

optimization, perhaps for benchmarking or test purposes.

=item I<-randStartVelocity>: boolean, optional

Set true to initialize particles with a random velocity. Otherwise particle
velocity is set to 0 on initalization.

A range based on 1/100th of -I<-posMax> - I<-posMin> is used for the initial
speed in each dimension of the velocity vector if a random start velocity is
used.

=item I<-stallSpeed>: positive number, optional

Speed below which a particle is considered to be stalled and is repositioned to
a new random location with a new initial speed.

By default I<-stallSpeed> is undefined but particles with a speed of 0 will be
repositioned.

=item I<-themWeight>: number, optional

Coefficient determining the influence of the neighbourhod best position on the
next iterations velocity. Defaults to 0.5.

See also I<-inertia> and I<-meWeight>.

=item I<-exitPlateau>: boolean, optional

Set true to have the optimization check for plateaus (regions where the fit
hasn't improved much for a while) during the search. The optimization ends when
a suitable plateau is detected following the burn in period.

Defaults to undefined (option disabled).

=item I<-exitPlateauDP>: number, optional

Specify the number of decimal places to compare between the current fitness
function value and the mean of the previous I<-exitPlateauWindow> values.

Defaults to 10.

=item I<-exitPlateauWindow>: number, optional

Specify the size of the window used to calculate the mean for comparison to
the current output of the fitness function.  Correlates to the minimum size of a
plateau needed to end the optimization.

Defaults to 10% of the number of iterations (I<-iterations>).

=item I<-exitPlateauBurnin>: number, optional

Determines how many iterations to run before checking for plateaus.

Defaults to 50% of the number of iterations (I<-iterations>).

=item I<-verbose>: flags, optional

If set to a non-zero value I<-verbose> determines the level of diagnostic print
reporting that is generated during optimization.

The following constants may be bitwise ored together to set logging options:

=over 4

=item * kLogBetter

prints particle details when its fit becomes bebtter than its previous best.

=item * kLogStall

prints particle details when its velocity reaches 0 or falls below the stall
threshold.

=item * kLogIter

Shows the current iteration number.

=item * kLogDetail

Shows additional details for some of the other logging options.

=item * kLogIterDetail

Shorthand for C<kLogIter | kLogIterDetail>

=back

=back

=item B<setParams (%parameters)>

Set or change optimization parameters. See I<-new> above for a description of
the parameters that may be supplied.

=item B<init ()>

Reinitialize the optimization. B<init ()> will be called during the first call
to B<optimize ()> if it hasn't already been called.

=item B<optimize ()>

Runs the minimization optimization. Returns the fit value of the best fit
found. The best possible fit is negative infinity.

B<optimize ()> may be called repeatedly to continue the fitting process. The fit
processing on each subsequent call will continue from where the last call left
off.

=item B<getParticleState ()>

Returns the vector of position

=item B<getBestParticles ([$n])>

Takes an optional count.

Returns a list containing the best $n particle numbers. If $n is not specified
only the best particle number is returned.

=item B<getParticleBestPos ($particleNum)>

Returns a list containing the best value of the fit and the vector of its point
in hyper space.

    my ($fit, @vector) = $pso->getParticleBestPos (3)

=item B<getIterationCount ()>

Return the number of iterations performed. This may be useful when the
I<-exitFit> criteria has been met or where multiple calls to I<optimize> have
been made.

=back

=head1 BUGS

None... I hope.

If any: A small script which yields the problem will probably be of help.