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class StepEngine( Engine )	Source

Move a walker in a random direction.

The StepEngine tries to move the parameters at most 4 times in a random direction.

Attributes from Engine

walkers, errdis, maxtrials, nstep, slow, rng, report, phantoms, verbose

Author Do Kester.

StepEngine( walkers, errdis, copy=None, **kwargs )

Constructor.

Parameters

• walkers : WalkerList
       walkers to be diffused
• errdis : ErrorDistribution
       error distribution to be used
• copy : StepEngine
       to be copied
• kwargs : for Engine
       "phantoms", "slow", "seed", "verbose"

copy( )

Return copy of this.

execute( kw, lowLhood, append=False, iteration=0 )

Execute the engine by diffusing the parameters.

Parameters

• kw : int
       index of walker to diffuse
• lowLhood : float
       lower limit in logLikelihood
• append : bool
       set walker in place or append
• iteration : int
       iteration number

Returns

• int : the number of successfull steps

Methods inherited from Engine

• bestBoost( problem, myFitter=None )
• setWalker( kw, problem, allpars, logL, walker=None, fitIndex=None )
• noBoost( walker )
• doBoost( walker )
• domain2Unit( problem, dval, kpar=None )
• unit2Domain( problem, uval, kpar=None )
• startJourney( unitStart )
• calcJourney( unitDistance )
• reportJourney( )
• makeIndex( np, val )
• reportCall( )
• reportSuccess( )
• reportReject( )
• reportFailed( )
• reportBest( )
• printReport( best=False )
• successRate( )
• getUnitMinmax( problem, lowLhood )
• getUnitRange( problem, lowLhood )