Golden Section Optimizer Class
Definition
Assembly: Extreme.Numerics (in Extreme.Numerics.dll) Version: 8.1.23
public class GoldenSectionOptimizer : OneDimensionalOptimizer
- Inheritance
- Object → ManagedIterativeAlgorithm<Double, Double, SolutionReport<Double, Double>> → ManagedIterativeAlgorithm<Double> → OneDimensionalOptimizer → GoldenSectionOptimizer
Remarks
Use the GoldenSectionOptimizer to find the minimum or a maximum of a function.
The ObjectiveFunction property must be set to a function of one variable that evaluates the objective function. The ExtremumType property specifies whether a maximum or a minimum of the objective function is requested.
The algorithm itself runs in two phases. In the bracketing phase, a search is made for an interval that is known to contain an extremum. This step is performed automatically when the algorithm is run. You can run it manually by calling one of the FindBracket(Double) methods. You can check the validity of a bracketing interval by inspecting the IsBracketValid property.
Once a bracketing interval has been found, the location phase begins. The exact location of the extremum is found by successively narrowing the bracketing interval. This phase always converges for continuous functions. The FindExtremum() method performs the location phase, and returns the best approximation to the extremum. Alternatively, one of the FindMaximum(Func<Double, Double>, Double, Double) or FindMinimum(Func<Double, Double>, Double, Double) methods can be used. This has the advantage that the objective function as well as an initial guess can be supplied with the method call.
The Extremum property returns the best approximation to the extremum. The EstimatedError property returns the uncertainty of the extremum. The ValueAtExtremum property returns the value of the objective function at the extremum. The Status property is a AlgorithmStatus value that indicates the outcome of the algorithm. A value of Normal shows normal termination. A value of Divergent usually indicates that a bracketing interval could not be found.
Convergence is tested using a simple convergence test based on the uncertainty in the location of the approximate extremum. The SolutionTest property returns a SimpleConvergenceTest<T> object that allows you to specify the desired Tolerance and specific ConvergenceCriterion.
Constructors
Golden | Constructs a new GoldenSectionOptimizer object. |
Golden | Constructs a new GoldenSectionOptimizer object. |
Properties
Convergence |
Gets the collection of convergence tests for the algorithm.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Derivative |
Gets or sets the derivative of the objective function.
(Inherited from OneDimensionalOptimizer) |
Estimated |
Gets a value indicating the size of the absolute
error of the result.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Evaluations |
Gets the number of evaluations needed to execute the algorithm.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Evaluations |
Gets the number of evaluations still available.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Extremum |
Gets the approximation to the extremum after the algorithm has run.
(Inherited from OneDimensionalOptimizer) |
Extremum |
Gets or sets the type of extremum.
(Inherited from OneDimensionalOptimizer) |
Has |
Indicates whether the degree of parallelism is a property that is shared
across instances.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
IsBracket |
Gets whether the algorithm's current bracket is valid.
(Inherited from OneDimensionalOptimizer) |
Iterations |
Gets the number of iterations needed by the
algorithm to reach the desired accuracy.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Iterations |
Gets the number of iterations remaining.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Max |
Gets or sets the maximum degree of parallelism enabled by this instance.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Max |
Gets or sets the maximum number of evaluations during the calculation.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Max | Gets or sets the maximum number of iterations
to use when approximating the roots of the target
function.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Min |
Gets or sets the minimum iterations that have to be performed.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Objective |
Gets or sets the objective function.
(Inherited from OneDimensionalOptimizer) |
Objective |
Gets or sets a function that computes the value of the objective function
and its derivative.
(Inherited from OneDimensionalOptimizer) |
Parallel |
Gets or sets the configuration for the parallel behavior of the algorithm.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Result |
Gets the result of an algorithm after it has executed.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Solution |
Gets the result of an algorithm after it has executed.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Solution |
Gets the convergence test that uses the solution of the optimization.
(Inherited from OneDimensionalOptimizer) |
Status |
Gets the AlgorithmStatus following
an execution of the algorithm.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Symbolic |
Gets or sets the objective function.
(Inherited from OneDimensionalOptimizer) |
Throw |
Gets or sets a value indicating whether to throw an
exception when the algorithm fails to converge.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Value |
Gets the value of the objective function at the approximation to the extremum after the algorithm has run.
(Inherited from OneDimensionalOptimizer) |
Methods
Equals | Determines whether the specified object is equal to the current object. (Inherited from Object) |
Evaluate |
Evaluates the objective function.
(Inherited from OneDimensionalOptimizer) |
Evaluate |
Evaluates the derivative of the objective function.
(Inherited from OneDimensionalOptimizer) |
Evaluate |
Evaluates the objective function and its derivative.
(Inherited from OneDimensionalOptimizer) |
Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object) |
Find |
Finds an interval that brackets the extremum, starting from the interval [0,1].
(Inherited from OneDimensionalOptimizer) |
Find |
Finds an interval that brackets the extremum, starting from an interval of unit width centered around the specified point.
(Inherited from OneDimensionalOptimizer) |
Find |
Finds an interval that brackets the extremum, starting from an interval with the specified bounds.
(Inherited from OneDimensionalOptimizer) |
Find |
Finds an interval that brackets the extremum, starting from an interval with the specified bounds and
interior point.
(Inherited from OneDimensionalOptimizer) |
Find |
Searches for an extremum.
(Inherited from OneDimensionalOptimizer) |
Find |
Computes a maximum of the specified function.
(Inherited from OneDimensionalOptimizer) |
Find |
Computes a maximum of the specified function.
(Inherited from OneDimensionalOptimizer) |
Find |
Computes a minimum of the specified function.
(Inherited from OneDimensionalOptimizer) |
Find |
Computes a minimum of the specified function.
(Inherited from OneDimensionalOptimizer) |
Get | Serves as the default hash function. (Inherited from Object) |
Get | Gets the Type of the current instance. (Inherited from Object) |
Increment |
Increments the number of evaluations by one.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Increment |
Increments the number of evaluations by the specified amount.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Iterate |
Performs one iteration of the algorithm.
(Overrides ManagedIterativeAlgorithm<T, TError, TReport>.Iterate()) |
Iterated |
Performs tasks after the iteration is completed, but before
the status of the algorithm is finalized.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Memberwise | Creates a shallow copy of the current Object. (Inherited from Object) |
OnConvergence |
Performs any tasks after the main algorithm has converged.
(Inherited from OneDimensionalOptimizer) |
OnFailure |
Performs any tasks after the main algorithm has failed to converge.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
OnInit |
Performs initialization before the first iteration.
(Overrides OneDimensionalOptimizer.OnInit()) |
Report |
Records the results of an algorithm in case it fails.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Report |
Records the results of an algorithm.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Report |
Records the results of a algorithm that converged successfully.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Reset |
Resets the number of evaluations to zero.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Restart |
Prepares the algorithm to be run again with possibly different inputs.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Run() |
Runs the algorithm.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Run( |
Runs the algorithm using the specified parallelization options.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Set |
Sets the results of an algorithm's execution.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Test |
Checks whether the algorithm has converged.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Thread |
Increments the number of evaluations by one.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Thread |
Increments the number of evaluations by the specified amount.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
Throw |
Interprets the AlgorithmStatus and
throws the appropriate exception.
(Inherited from ManagedIterativeAlgorithm<T, TError, TReport>) |
ToString | Returns a string that represents the current object. (Inherited from Object) |