Package apple.metalperformanceshaders

Class MPSCNNPoolingMaxGradient

  • All Implemented Interfaces:
    NSCoding, NSCopying, NSSecureCoding, NSObject
    public class MPSCNNPoolingMaxGradient
extends MPSCNNPoolingGradient
    MPSCNNPoolingMaxGradient [@dependency] This depends on Metal.framework Specifies the filter for computing the gradient of the max pooling filter. The operation backpropagates a gradient vector using chain rule. Dilated Max pooling forward pass is defined as: out(x) = max_{dx \in Window(x)} in(s*x+D*dx), where the pooling window definition 'Window(x)' follows MPSCNNPooling specification, 's' is the pixel stride and in() is the source input image and D is the dilation factor. For MPSCNNPoolingMaxGradient the dilationRate 'D' is one. NOTE: For even-sized pooling windows with dilation rate greater than one the effective pooling window is centered around s*x with non-even windows leaning towards top-left corner. For example if kernel width = 2, dilation rate = 3, then the pooling considers positions '-2' and '+1' relative to the pooling window center 's*x'. Hence the partial derivative of the output value wrt. to the input value needed in the gradient backpropagation in MPSCNNPoolingGradient is: d out(x)/d in(y) = delta_{x_m, y}, where delta_{x,y} is the Kronecker delta symbol (see MPSCNNPoolingAverageGradient) and x_m is the index of the maximum value in the corresponding pooling window. In practice this means that the gradient value for the destination image at pixel 'x' is the sum over these contributions coming from all pooling windows that contribute to the max pooling computation in the forward pass, multiplied by the input gradient value in the source area of the corresponding pooling window. If there are multiple maximal values within a single pooling window one of them is picked for the gradient and this decision is implementation specific, which means that it can vary between different architectures and even between different filter parameters. Note: The gradient max pooling needs the secondary input image in order to compute the indices of maximal values for each pooling window, but this means redundant computations. Later we may add encode calls to MPSCNNPoolingMax that produce a state that contains the coordinates of the maximal values to be consumed by the gradient filters.

    • Constructor Detail

      • MPSCNNPoolingMaxGradient

        protected MPSCNNPoolingMaxGradient​(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 MPSCNNPoolingMaxGradient initWithCoderDevice​(NSCoder aDecoder,
                                                    java.lang.Object device)
        NSSecureCoding compatability See @ref MPSKernel#initWithCoder.
        Overrides:
        initWithCoderDevice in class MPSCNNPoolingGradient
        Parameters:
        aDecoder - The NSCoder subclass with your serialized MPSCNNPoolingMaxGradient
        device - The MTLDevice on which to make the MPSCNNPoolingMaxGradient
        Returns:
        A new MPSCNNPoolingMaxGradient object, or nil if failure.

      • initWithDevice

        public MPSCNNPoolingMaxGradient initWithDevice​(java.lang.Object device)
        Description copied from class: MPSCNNGradientKernel
        Standard init with default properties per filter type
        Overrides:
        initWithDevice in class MPSCNNPoolingGradient
        Parameters:
        device - The device that the filter will be used on. May not be NULL.
        Returns:
        A pointer to the newly initialized object. This will fail, returning nil if the device is not supported. Devices must be MTLFeatureSet_iOS_GPUFamily2_v1 or later.

      • initWithDeviceKernelWidthKernelHeight

        public MPSCNNPoolingMaxGradient initWithDeviceKernelWidthKernelHeight​(MTLDevice device,
                                                                      long kernelWidth,
                                                                      long kernelHeight)
        Description copied from class: MPSCNNPoolingGradient
        Initialize a gradient pooling filter
        Overrides:
        initWithDeviceKernelWidthKernelHeight in class MPSCNNPoolingGradient
        Parameters:
        device - The device the filter will run on
        kernelWidth - The width of the kernel. Can be an odd or even value.
        kernelHeight - The height of the kernel. Can be an odd or even value.
        Returns:
        A valid MPSCNNPoolingGradient object or nil, if failure.

      • initWithDeviceKernelWidthKernelHeightStrideInPixelsXStrideInPixelsY

        public MPSCNNPoolingMaxGradient initWithDeviceKernelWidthKernelHeightStrideInPixelsXStrideInPixelsY​(MTLDevice device,
                                                                                                    long kernelWidth,
                                                                                                    long kernelHeight,
                                                                                                    long strideInPixelsX,
                                                                                                    long strideInPixelsY)
        Initialize a gradient max pooling filter
        Overrides:
        initWithDeviceKernelWidthKernelHeightStrideInPixelsXStrideInPixelsY in class MPSCNNPoolingGradient
        Parameters:
        device - The device the filter will run on
        kernelWidth - The width of the kernel. Can be an odd or even value.
        kernelHeight - The height of the kernel. Can be an odd or even value.
        strideInPixelsX - The input stride (upsampling factor) in the x dimension.
        strideInPixelsY - The input stride (upsampling factor) in the y dimension.
        Returns:
        A valid MPSCNNPoolingGradient 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 MPSCNNPoolingGradient

      • version_static

        public static long version_static()