// Mechanical adaptation of OA's grouped Conv2d input adjoint.
// Donor: source/cpp/lib/oa/ml/shader/compute/nn/conv/conv2dBwdData.slang
import storage;
import attributes;
struct PushConstants {
uint output_gradient_index;
uint weight_index;
uint input_gradient_index;
uint batch_size;
uint input_channels;
uint output_channels;
uint input_height;
uint input_width;
uint kernel_size;
uint stride;
uint padding;
uint output_height;
uint output_width;
uint groups;
};
[[vk::push_constant]] PushConstants push;
[[vk::binding(0, 0)]] RWByteAddressBuffer storage_buffers[];
[kernel_name("conv_2d_backward")]
[domain("ml")]
[variant("generic")]
[dtype("f32")]
[status("experimental")]
[shader("compute")]
[numthreads(256, 1, 1)]
void main(uint3 thread_id : SV_DispatchThreadID) {
uint input_index = thread_id.x;
uint input_count =
push.batch_size * push.input_channels * push.input_height * push.input_width;
if (input_index >= input_count) {
return;
}
uint input_x = input_index % push.input_width;
uint quotient = input_index / push.input_width;
uint input_y = quotient % push.input_height;
quotient /= push.input_height;
uint input_channel = quotient % push.input_channels;
uint batch = quotient / push.input_channels;
uint input_channels_per_group = push.input_channels / push.groups;
uint output_channels_per_group = push.output_channels / push.groups;
uint group = input_channel / input_channels_per_group;
uint local_input_channel = input_channel - group * input_channels_per_group;
uint output_channel_base = group * output_channels_per_group;
float gradient = 0.0f;
for (uint local_output_channel = 0; local_output_channel < output_channels_per_group; ++local_output_channel) {
uint output_channel = output_channel_base + local_output_channel;
for (uint kernel_y = 0; kernel_y < push.kernel_size; ++kernel_y) {
for (uint kernel_x = 0; kernel_x < push.kernel_size; ++kernel_x) {
int output_y_numerator = int(input_y) - int(kernel_y) + int(push.padding);
int output_x_numerator = int(input_x) - int(kernel_x) + int(push.padding);
if (
output_y_numerator < 0 || output_x_numerator < 0
|| output_y_numerator % int(push.stride) != 0
|| output_x_numerator % int(push.stride) != 0
) {
continue;
}
int output_y = output_y_numerator / int(push.stride);
int output_x = output_x_numerator / int(push.stride);
if (
output_y >= int(push.output_height)
|| output_x >= int(push.output_width)
) {
continue;
}
uint output_offset =
((batch * push.output_channels + output_channel) * push.output_height
+ uint(output_y)) * push.output_width + uint(output_x);
uint weight_offset =
((output_channel * input_channels_per_group + local_input_channel)
* push.kernel_size + kernel_y) * push.kernel_size + kernel_x;
gradient += load_f32(storage_buffers[push.output_gradient_index], output_offset)
* load_f32(storage_buffers[push.weight_index], weight_offset);
}
}
}
store_f32(storage_buffers[push.input_gradient_index], input_index, gradient);
}