MPSCNNSubtractGradient(3)

NAME
MPSCNNSubtractGradient

SYNOPSIS

#import <MPSCNNMath.h>

Inherits MPSCNNArithmeticGradient.

  Instance Methods
(nonnull instancetype) - initWithDevice:isSecondarySourceFilter:

  Additional Inherited Members

Detailed Description

This depends on Metal.framework. Specifies the subtraction gradient operator. This arithmetic gradient filter requires the following inputs: gradient image from the previous layer (going backwards) and either the primary or the secondary source image from the forward pass. You will need a separate filter for the primary and secondary source images.

Without broadcasting, the arithmetic subtract gradient operation for the primary source image is a copy operation on the input gradient image (for x - y, d/dx(x - y) = 1). This copy operation can be optimized away by the graph interface.

For the secondary source image, the result is a negation of the gradient image from the previous layer (for x - y, d/dy(x - y) = -1).

Setting the broadcasting parameters results in a reduction operation (sum) across all of the applicable broadcasting dimensions (rows, columns, feature channels, or any combination thereof) to produce the destination image of the size that matches the primary/secondary input images used in the forward pass.

Method Documentation

  - (nonnull instancetype) initWithDevice: (nonnull id< MTLDevice >) device(BOOL) isSecondarySourceFilter
Initialize the subtraction gradient operator.

Parameters:
    device The device the filter will run on.
    isSecondarySourceFilter A boolean indicating whether the arithmetic gradient filter is operating on the primary or secondary source image from the forward pass.

Returns:
    A valid MPSCNNSubtractGradient object or nil, if failure.

Reimplemented from MPSCNNArithmeticGradient.

Author

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