GeezerVison

####################################################### # Copyright (c) 2020, ArrayFire # All rights reserved. # # This file is distributed under 3-clause BSD license. # The complete license agreement can be obtained at: # http://arrayfire.com/licenses/BSD-3-Clause ######################################################## """ Machine learning functions - Pool 2D, ND, maxpooling, minpooling, meanpooling - Forward and backward convolution passes """ from .library import * from .array import * def convolve2GradientNN(incoming_gradient, original_signal, original_kernel, convolved_output, stride = (1, 1), padding = (0, 0), dilation = (1, 1), gradType = CONV_GRADIENT.DEFAULT): """ Function for calculating backward pass gradient of 2D convolution. This function calculates the gradient with respect to the output of the \ref convolve2NN() function that uses the machine learning formulation for the dimensions of the signals and filters Multiple signals and filters can be batched against each other, however their dimensions must match. Example: Signals with dimensions: d0 x d1 x d2 x Ns Filters with dimensions: d0 x d1 x d2 x Nf Resulting Convolution: d0 x d1 x Nf x Ns Parameters ----------- incoming_gradient: af.Array - Gradients to be distributed in backwards pass original_signal: af.Array - A 2 dimensional signal or batch of 2 dimensional signals. original_kernel: af.Array - A 2 dimensional kernel or batch of 2 dimensional kernels. convolved_output: af.Array - output of forward pass of convolution stride: tuple of ints. default: (1, 1). - Specifies how much to stride along each dimension padding: tuple of ints. default: (0, 0). - Specifies signal padding along each dimension dilation: tuple of ints. default: (1, 1). - Specifies how much to dilate kernel along each dimension before convolution Returns -------- output: af.Array - Gradient wrt/requested gradient type """ output = Array() stride_dim = dim4(stride[0], stride[1]) padding_dim = dim4(padding[0], padding[1]) dilation_dim = dim4(dilation[0], dilation[1]) safe_call(backend.get().af_convolve2_gradient_nn( c_pointer(output.arr), incoming_gradient.arr, original_signal.arr, original_kernel.arr, convolved_output.arr, 2, c_pointer(stride_dim), 2, c_pointer(padding_dim), 2, c_pointer(dilation_dim), gradType.value)) return output