Package org.hipparchus.optim.univariate
Class MultiStartUnivariateOptimizer
java.lang.Object
org.hipparchus.optim.BaseOptimizer<UnivariatePointValuePair>
org.hipparchus.optim.univariate.UnivariateOptimizer
org.hipparchus.optim.univariate.MultiStartUnivariateOptimizer
Special implementation of the
This class wraps an optimizer in order to use it several times in turn with different starting points (trying to avoid being trapped in a local extremum when looking for a global one).
UnivariateOptimizer
interface
adding multistart features to an existing optimizer.
This class wraps an optimizer in order to use it several times in turn with different starting points (trying to avoid being trapped in a local extremum when looking for a global one).

Field Summary
Fields inherited from class org.hipparchus.optim.BaseOptimizer
evaluations, iterations

Constructor Summary
ConstructorDescriptionMultiStartUnivariateOptimizer
(UnivariateOptimizer optimizer, int starts, RandomGenerator generator) Create a multistart optimizer from a singlestart optimizer. 
Method Summary
Modifier and TypeMethodDescriptionprotected UnivariatePointValuePair
Performs the bulk of the optimization algorithm.int
Gets the number of evaluations of the objective function.Gets all the optima found during the last call tooptimize
.optimize
(OptimizationData... optData) Stores data and performs the optimization.Methods inherited from class org.hipparchus.optim.univariate.UnivariateOptimizer
computeObjectiveValue, getGoalType, getMax, getMin, getStartValue, parseOptimizationData
Methods inherited from class org.hipparchus.optim.BaseOptimizer
getConvergenceChecker, getIterations, getMaxEvaluations, getMaxIterations, incrementEvaluationCount, incrementIterationCount, optimize

Constructor Details

MultiStartUnivariateOptimizer
public MultiStartUnivariateOptimizer(UnivariateOptimizer optimizer, int starts, RandomGenerator generator) Create a multistart optimizer from a singlestart optimizer. Parameters:
optimizer
 Singlestart optimizer to wrap.starts
 Number of starts to perform. Ifstarts == 1
, theoptimize
methods will return the same solution asoptimizer
would.generator
 Random generator to use for restarts. Throws:
MathIllegalArgumentException
 ifstarts < 1
.


Method Details

getEvaluations
public int getEvaluations()Gets the number of evaluations of the objective function. The number of evaluations corresponds to the last call to theoptimize
method. It is 0 if the method has not been called yet. Overrides:
getEvaluations
in classBaseOptimizer<UnivariatePointValuePair>
 Returns:
 the number of evaluations of the objective function.

getOptima
Gets all the optima found during the last call tooptimize
. The optimizer stores all the optima found during a set of restarts. Theoptimize
method returns the best point only. This method returns all the points found at the end of each starts, including the best one already returned by theoptimize
method.
The returned array as one element for each start as specified in the constructor. It is ordered with the results from the runs that did converge first, sorted from best to worst objective value (i.e in ascending order if minimizing and in descending order if maximizing), followed bynull
elements corresponding to the runs that did not converge. This means all elements will benull
if theoptimize
method did throw an exception. This also means that if the first element is notnull
, it is the best point found across all starts. Returns:
 an array containing the optima.
 Throws:
MathIllegalStateException
 ifoptimize
has not been called.

optimize
Stores data and performs the optimization.The list of parameters is openended so that subclasses can extend it with arguments specific to their concrete implementations.
When the method is called multiple times, instance data is overwritten only when actually present in the list of arguments: when not specified, data set in a previous call is retained (and thus is optional in subsequent calls).
Important note: Subclasses must override
BaseOptimizer.parseOptimizationData(OptimizationData[])
if they need to register their own options; but then, they must also callsuper.parseOptimizationData(optData)
within that method. Overrides:
optimize
in classUnivariateOptimizer
 Parameters:
optData
 Optimization data. In addition to those documented inBaseOptimizer
, this method will register the following data: Returns:
 a point/value pair that satisfies the convergence criteria.
 Throws:
MathIllegalStateException
 ifoptData
does not contain an instance ofMaxEval
orSearchInterval
.

doOptimize
Performs the bulk of the optimization algorithm. Specified by:
doOptimize
in classBaseOptimizer<UnivariatePointValuePair>
 Returns:
 the point/value pair giving the optimal value of the objective function.
