Package apple.metalperformanceshaders

Class MPSNNInitialGradient

  • All Implemented Interfaces:
    NSCoding, NSCopying, NSSecureCoding, NSObject
    public class MPSNNInitialGradient
extends MPSCNNKernel
    MPSNNInitialGradient [@dependency] This depends on Metal.framework The MPSCNNInitialGradient filter specifies a layer which computes the initial gradient for an aribitrary input image. The operation itself is extremely simple: it computes the gradient of the input image with itself, resulting in an output image which is filled with '1's for all the inputs that were used. This serves as the starting point for the computation of gradients between arbitrary images in a network. Example: Suppose that we want to compute gradients for a function that multiplies together two losses: f = f(L1, L2) = L1 * L2 The losses themselves are computed from some inputs x1,x2: L1 = L1(x1), L2 = L2(x2) The filters to compute f, L1, L2 are: f = MPSCNNMultiply(L1, L2), where L1 = MPSNNForwardLoss1(x1) and L2 = MPSNNForwardLoss1(x2) To compute df/dx1 we apply the chain rule: df/dx1 = d(L1 * L2)/dx1 = d(L1 * L2)/dL1 * dL1/dx1 + d(L1 * L2)/dL2 * dL2/dx1 = d(L1 * L2)/dL1 * dL1/dx1 = L2 * dL1/dx1 The MPSCNNMultiplyGradient filter computes for f = L1 * L2 forward op: dL/dL1 = dL/df * df/dL1 = dL/df * L2 and dL/dL2 = dL/df * df/dL2 = dL/df * L1 where dL/df is the input gradient of the chain rule / backpropagation algorithm. But in our case we want MPSCNNMultiplyGradient to compute the gradient: df/dL1 = d(L1 * L2)/dL1 = L2, which shows that L = f, which means that dL/dL1 = df/df * df/dL1 = 1 * L2, which shows that we get the correct gradient by providing unit input as input gradient to the MPSCNNMultiplyGradient.

    • Constructor Detail

      • MPSNNInitialGradient

        protected MPSNNInitialGradient​(org.moe.natj.general.Pointer peer)

    • Method Detail

      • accessInstanceVariablesDirectly

        public static boolean accessInstanceVariablesDirectly()

      • allocWithZone

        public static java.lang.Object allocWithZone​(org.moe.natj.general.ptr.VoidPtr zone)

      • automaticallyNotifiesObserversForKey

        public static boolean automaticallyNotifiesObserversForKey​(java.lang.String key)

      • cancelPreviousPerformRequestsWithTarget

        public static void cancelPreviousPerformRequestsWithTarget​(java.lang.Object aTarget)

      • cancelPreviousPerformRequestsWithTargetSelectorObject

        public static void cancelPreviousPerformRequestsWithTargetSelectorObject​(java.lang.Object aTarget,
                                                                         org.moe.natj.objc.SEL aSelector,
                                                                         java.lang.Object anArgument)

      • classFallbacksForKeyedArchiver

        public static NSArray<java.lang.String> classFallbacksForKeyedArchiver()

      • classForKeyedUnarchiver

        public static org.moe.natj.objc.Class classForKeyedUnarchiver()

      • debugDescription_static

        public static java.lang.String debugDescription_static()

      • description_static

        public static java.lang.String description_static()

      • hash_static

        public static long hash_static()

      • initWithCoderDevice

        public MPSNNInitialGradient initWithCoderDevice​(NSCoder aDecoder,
                                                java.lang.Object device)
        Description copied from class: MPSCNNKernel
        NSSecureCoding compatability While the standard NSSecureCoding/NSCoding method -initWithCoder: should work, since the file can't know which device your data is allocated on, we have to guess and may guess incorrectly. To avoid that problem, use initWithCoder:device instead.
        Overrides:
        initWithCoderDevice in class MPSCNNKernel
        Parameters:
        aDecoder - The NSCoder subclass with your serialized MPSKernel
        device - The MTLDevice on which to make the MPSKernel
        Returns:
        A new MPSKernel object, or nil if failure.

      • initWithDevice

        public MPSNNInitialGradient initWithDevice​(java.lang.Object device)
        Initializes a MPSNNInitialGradient kernel.
        Overrides:
        initWithDevice in class MPSCNNKernel
        Parameters:
        device - The MTLDevice on which this MPSNNInitialGradient filter will be used.
        Returns:
        A valid MPSNNInitialGradient object or nil, if failure.

      • instanceMethodSignatureForSelector

        public static NSMethodSignature instanceMethodSignatureForSelector​(org.moe.natj.objc.SEL aSelector)

      • instancesRespondToSelector

        public static boolean instancesRespondToSelector​(org.moe.natj.objc.SEL aSelector)

      • isSubclassOfClass

        public static boolean isSubclassOfClass​(org.moe.natj.objc.Class aClass)

      • keyPathsForValuesAffectingValueForKey

        public static NSSet<java.lang.String> keyPathsForValuesAffectingValueForKey​(java.lang.String key)

      • new_objc

        public static java.lang.Object new_objc()

      • resolveClassMethod

        public static boolean resolveClassMethod​(org.moe.natj.objc.SEL sel)

      • resolveInstanceMethod

        public static boolean resolveInstanceMethod​(org.moe.natj.objc.SEL sel)

      • setVersion_static

        public static void setVersion_static​(long aVersion)

      • superclass_static

        public static org.moe.natj.objc.Class superclass_static()

      • supportsSecureCoding

        public static boolean supportsSecureCoding()

      • _supportsSecureCoding

        public boolean _supportsSecureCoding()
        Description copied from interface: NSSecureCoding
        This property must return YES on all classes that allow secure coding. Subclasses of classes that adopt NSSecureCoding and override initWithCoder: must also override this method and return YES. The Secure Coding Guide should be consulted when writing methods that decode data.
        Specified by:
        _supportsSecureCoding in interface NSSecureCoding
        Overrides:
        _supportsSecureCoding in class MPSCNNKernel

      • version_static

        public static long version_static()