GKMinMaxStrategist Class

Definition

Game AI that evaluates potential game states, scores them, and attempts to maximize it's own score while minimizing it's opponents.

[Foundation.Register("GKMinmaxStrategist", true)]
[ObjCRuntime.Introduced(ObjCRuntime.PlatformName.iOS, 9, 0, ObjCRuntime.PlatformArchitecture.All, null)]
[ObjCRuntime.Introduced(ObjCRuntime.PlatformName.MacOSX, 10, 11, ObjCRuntime.PlatformArchitecture.Arch64, null)]
public class GKMinMaxStrategist : Foundation.NSObject, GameplayKit.IGKStrategist, IDisposable
type GKMinMaxStrategist = class
    inherit NSObject
    interface IGKStrategist
    interface INativeObject
    interface IDisposable
Inheritance
GKMinMaxStrategist
Attributes
Implements

Remarks

The GKMinMaxStrategist class is an implementation of the minimax algorithm, optimized for space efficiency. Developers do not subclass GKMinMaxStrategist, but instead create game-specific implementations of IGKGameModelPlayer, IGKGameModel, and IGKGameModelUpdate. This is discussed in detail in the "AI Opponent" section of the remarks section of the N:GameplayKit namespace documentation.

Perhaps because GKMinMaxStrategist is a highly-optimized implementation, it's failure modes are difficult to debug. Typically, a mistake in the configuration of GKMinMaxStrategist or in the implementation of the related game classes results in an null returned by GetBestMove(IGKGameModelPlayer) with no error message in the console or system log. The following sequence diagram may be of some help in placing breakpoints:

Because GetBestMove(IGKGameModelPlayer) is very expensive, developers should typically call it from a background T:System.Threading.Tasks.Task.

Constructors

GKMinMaxStrategist()

Default constructor, initializes a new instance of this class.

GKMinMaxStrategist(IntPtr)

A constructor used when creating managed representations of unmanaged objects; Called by the runtime.

GKMinMaxStrategist(NSObjectFlag)

Constructor to call on derived classes to skip initialization and merely allocate the object.

Properties

Class (Inherited from NSObject)
ClassHandle

The handle for this class.

DebugDescription

A developer-meaningful description of this object.

(Inherited from NSObject)
Description

Description of the object, the Objective-C version of ToString.

(Inherited from NSObject)
GameModel

The IGKGameModel representing the current state of the game.

Handle

Handle (pointer) to the unmanaged object representation.

(Inherited from NSObject)
IsDirectBinding (Inherited from NSObject)
IsProxy (Inherited from NSObject)
MaxLookAheadDepth

The number of player turns to evaluate. Exponentially expensive.

RandomSource

Used to break ties among moves in GetBestMove(IGKGameModelPlayer) and to choose a move in GetRandomMove(IGKGameModelPlayer, nint).

RetainCount

Returns the current Objective-C retain count for the object.

(Inherited from NSObject)
Self (Inherited from NSObject)
Superclass (Inherited from NSObject)
SuperHandle

Handle used to represent the methods in the base class for this NSObject.

(Inherited from NSObject)
Zone (Inherited from NSObject)

Methods

AddObserver(NSObject, NSString, NSKeyValueObservingOptions, IntPtr)

Registers an object for being observed externally (using NSString keyPath).   Observed changes are dispatched to the observer’s object ObserveValue(NSString, NSObject, NSDictionary, IntPtr) method.

(Inherited from NSObject)
AddObserver(NSObject, String, NSKeyValueObservingOptions, IntPtr)

Registers an object for being observed externally (using string keyPath).   Observed changes are dispatched to the observer’s object ObserveValue(NSString, NSObject, NSDictionary, IntPtr) method.

(Inherited from NSObject)
AddObserver(NSString, NSKeyValueObservingOptions, Action<NSObservedChange>)

Registers an object for being observed externally using an arbitrary method.

(Inherited from NSObject)
AddObserver(String, NSKeyValueObservingOptions, Action<NSObservedChange>)

Registers an object for being observed externally using an arbitrary method.

(Inherited from NSObject)
AwakeFromNib()

Called after the object has been loaded from the nib file. Overriders must call base.AwakeFromNib().

(Inherited from NSObject)
BeginInvokeOnMainThread(Action) (Inherited from NSObject)
BeginInvokeOnMainThread(Selector, NSObject)

Invokes asynchrously the specified code on the main UI thread.

(Inherited from NSObject)
Bind(NSString, NSObject, String, NSDictionary) (Inherited from NSObject)
Bind(String, NSObject, String, NSDictionary) (Inherited from NSObject)
BindingInfo(String) (Inherited from NSObject)
BindingOptionDescriptions(String) (Inherited from NSObject)
BindingValueClass(String) (Inherited from NSObject)
CommitEditing() (Inherited from NSObject)
CommitEditing(NSObject, Selector, IntPtr) (Inherited from NSObject)
ConformsToProtocol(IntPtr)

Invoked to determine if this object implements the specified protocol.

(Inherited from NSObject)
Copy()

Performs a copy of the underlying Objective-C object.

(Inherited from NSObject)
DangerousAutorelease() (Inherited from NSObject)
DangerousRelease() (Inherited from NSObject)
DangerousRetain() (Inherited from NSObject)
DidChange(NSKeyValueChange, NSIndexSet, NSString)

Indicates a change occurred to the indexes for a to-many relationship.

(Inherited from NSObject)
DidChange(NSString, NSKeyValueSetMutationKind, NSSet) (Inherited from NSObject)
DidChangeValue(String)

Indicates that a change occurred on the specified key.

(Inherited from NSObject)
Dispose()

Releases the resources used by the NSObject object.

(Inherited from NSObject)
Dispose(Boolean)

Releases the resources used by the NSObject object.

(Inherited from NSObject)
DoesNotRecognizeSelector(Selector)

Indicates that this object does not recognize the specified selector.

(Inherited from NSObject)
Equals(NSObject) (Inherited from NSObject)
Equals(Object) (Inherited from NSObject)
ExposedBindings() (Inherited from NSObject)
GetBestMove(IGKGameModelPlayer)

Calculates the IGKGameModelUpdate that provides the greatest advantage to player, constrained by MaxLookAheadDepth.

GetBestMoveForActivePlayer()

Returns the best possible move for the currently active player.

GetBindingInfo(NSString) (Inherited from NSObject)
GetBindingOptionDescriptions(NSString) (Inherited from NSObject)
GetBindingValueClass(NSString) (Inherited from NSObject)
GetDictionaryOfValuesFromKeys(NSString[])

Retrieves the values of the specified keys.

(Inherited from NSObject)
GetHashCode()

Generates a hash code for the current instance.

(Inherited from NSObject)
GetMethodForSelector(Selector) (Inherited from NSObject)
GetNativeField(String) (Inherited from NSObject)
GetNativeHash() (Inherited from NSObject)
GetRandomMove(IGKGameModelPlayer, nint)

Returns a random move among the numMovesToConsider best moves.

Init() (Inherited from NSObject)
InitializeHandle(IntPtr) (Inherited from NSObject)
InitializeHandle(IntPtr, String) (Inherited from NSObject)
Invoke(Action, Double) (Inherited from NSObject)
Invoke(Action, TimeSpan) (Inherited from NSObject)
InvokeOnMainThread(Action) (Inherited from NSObject)
InvokeOnMainThread(Selector, NSObject)

Invokes synchrously the specified code on the main UI thread.

(Inherited from NSObject)
IsEqual(NSObject) (Inherited from NSObject)
IsKindOfClass(Class) (Inherited from NSObject)
IsMemberOfClass(Class) (Inherited from NSObject)
MarkDirty()

Promotes a regular peer object (IsDirectBinding is true) into a toggleref object.

(Inherited from NSObject)
MutableCopy()

Creates a mutable copy of the specified NSObject.

(Inherited from NSObject)
ObjectDidEndEditing(NSObject) (Inherited from NSObject)
ObserveValue(NSString, NSObject, NSDictionary, IntPtr)

Indicates that the value at the specified keyPath relative to this object has changed.

(Inherited from NSObject)
PerformSelector(Selector) (Inherited from NSObject)
PerformSelector(Selector, NSObject) (Inherited from NSObject)
PerformSelector(Selector, NSObject, Double)

Invokes the selector on the current instance and if the obj is not null, it passes this as its single parameter.

(Inherited from NSObject)
PerformSelector(Selector, NSObject, Double, NSString[]) (Inherited from NSObject)
PerformSelector(Selector, NSObject, NSObject) (Inherited from NSObject)
PerformSelector(Selector, NSThread, NSObject, Boolean) (Inherited from NSObject)
PerformSelector(Selector, NSThread, NSObject, Boolean, NSString[]) (Inherited from NSObject)
PrepareForInterfaceBuilder() (Inherited from NSObject)
RemoveObserver(NSObject, NSString)

Stops the specified observer from receiving further notifications of changed values for the specified keyPath.

(Inherited from NSObject)
RemoveObserver(NSObject, NSString, IntPtr)

Stops the specified observer from receiving further notifications of changed values for the specified keyPath and context.

(Inherited from NSObject)
RemoveObserver(NSObject, String)

Stops the specified observer from receiving further notifications of changed values for the specified keyPath.

(Inherited from NSObject)
RemoveObserver(NSObject, String, IntPtr)

Stops the specified observer from receiving further notifications of changed values for the specified keyPath and context.

(Inherited from NSObject)
RespondsToSelector(Selector)

Whether this object recognizes the specified selector.

(Inherited from NSObject)
SetNativeField(String, NSObject) (Inherited from NSObject)
SetNilValueForKey(NSString)

Sets the value of the specified key to null.

(Inherited from NSObject)
SetValueForKey(NSObject, NSString)

Sets the value of the property specified by the key to the specified value.

(Inherited from NSObject)
SetValueForKeyPath(IntPtr, NSString)

A constructor used when creating managed representations of unmanaged objects; Called by the runtime.

(Inherited from NSObject)
SetValueForKeyPath(NSObject, NSString)

Sets the value of a property that can be reached using a keypath.

(Inherited from NSObject)
SetValueForUndefinedKey(NSObject, NSString)

Indicates an attempt to write a value to an undefined key. If not overridden, raises an NSUndefinedKeyException.

(Inherited from NSObject)
SetValuesForKeysWithDictionary(NSDictionary)

Sets the values of this NSObject to those in the specified dictionary.

(Inherited from NSObject)
ToString()

Returns a string representation of the value of the current instance.

(Inherited from NSObject)
Unbind(NSString) (Inherited from NSObject)
Unbind(String) (Inherited from NSObject)
ValueForKey(NSString)

Returns the value of the property associated with the specified key.

(Inherited from NSObject)
ValueForKeyPath(NSString)

Returns the value of a property that can be reached using a keypath.

(Inherited from NSObject)
ValueForUndefinedKey(NSString)

Indicates an attempt to read a value of an undefined key. If not overridden, raises an NSUndefinedKeyException.

(Inherited from NSObject)
WillChange(NSKeyValueChange, NSIndexSet, NSString)

Indicates that the values of the specified indices in the specified key are about to change.

(Inherited from NSObject)
WillChange(NSString, NSKeyValueSetMutationKind, NSSet) (Inherited from NSObject)
WillChangeValue(String)

Indicates that the value of the specified key is about to change.

(Inherited from NSObject)

Extension Methods

ObjectDidBeginEditing(NSObject, INSEditor)
ObjectDidEndEditing(NSObject, INSEditor)
GetValidModes(NSObject, NSFontPanel)
ValidateToolbarItem(NSObject, NSToolbarItem)
GetDebugDescription(INSObjectProtocol)
AcceptsPreviewPanelControl(NSObject, QLPreviewPanel)
BeginPreviewPanelControl(NSObject, QLPreviewPanel)
EndPreviewPanelControl(NSObject, QLPreviewPanel)
GetAccessibilityCustomRotors(NSObject)

Gets the array of UIAccessibilityCustomRotor objects appropriate for this object.

SetAccessibilityCustomRotors(NSObject, UIAccessibilityCustomRotor[])

Sets the array of UIAccessibilityCustomRotor objects appropriate for this object.

Applies to

See also