in src/tensorflow/lite/kernels/internal/reference/transpose_conv.h [25:112]
inline void TransposeConv(
const ConvParams& params, const RuntimeShape& input_shape,
const float* input_data, const RuntimeShape& filter_shape,
const float* filter_data, const RuntimeShape& bias_shape,
const float* bias_data, const RuntimeShape& output_shape,
float* output_data, const RuntimeShape& im2col_shape, float* im2col_data) {
const int stride_width = params.stride_width;
const int stride_height = params.stride_height;
const int pad_width = params.padding_values.width;
const int pad_height = params.padding_values.height;
TFLITE_DCHECK_EQ(input_shape.DimensionsCount(), 4);
TFLITE_DCHECK_EQ(filter_shape.DimensionsCount(), 4);
TFLITE_DCHECK_EQ(output_shape.DimensionsCount(), 4);
(void)im2col_data; // only used in optimized code.
(void)im2col_shape; // only used in optimized code.
const int batches = MatchingDim(input_shape, 0, output_shape, 0);
const int input_depth = MatchingDim(input_shape, 3, filter_shape, 3);
const int output_depth = MatchingDim(filter_shape, 0, output_shape, 3);
const int input_height = input_shape.Dims(1);
const int input_width = input_shape.Dims(2);
const int filter_height = filter_shape.Dims(1);
const int filter_width = filter_shape.Dims(2);
const int output_height = output_shape.Dims(1);
const int output_width = output_shape.Dims(2);
if (bias_data) {
TFLITE_DCHECK_EQ(bias_shape.FlatSize(), output_depth);
}
// Although transpose convolution simplifies to convolution with transposed
// weights for strides of 1, non-unitary striding complicates matters. To
// keep this reference implementation as clear as possible, we use a
// "scatter" access pattern, where we loop through all the input elements,
// computing their influence on the output, rather than looping through the
// output elements in the typical "gather" access pattern of a conv. We
// therefore must initialize the output array to zero.
const int num_elements = output_shape.FlatSize();
for (int i = 0; i < num_elements; i++) {
output_data[i] = 0.0f;
}
// Loop through input elements one at a time.
for (int batch = 0; batch < batches; ++batch) {
for (int in_y = 0; in_y < input_height; ++in_y) {
for (int in_x = 0; in_x < input_width; ++in_x) {
for (int in_channel = 0; in_channel < input_depth; ++in_channel) {
// Loop through the output elements it will influence
const int out_x_origin = (in_x * stride_width) - pad_width;
const int out_y_origin = (in_y * stride_height) - pad_height;
for (int filter_y = 0; filter_y < filter_height; ++filter_y) {
for (int filter_x = 0; filter_x < filter_width; ++filter_x) {
for (int out_channel = 0; out_channel < output_depth;
++out_channel) {
// Compute output element location
const int out_x = out_x_origin + filter_x;
const int out_y = out_y_origin + filter_y;
// We cannot accumulate out of bounds
if ((out_x >= 0) && (out_x < output_width) && (out_y >= 0) &&
(out_y < output_height)) {
float input_value = input_data[Offset(
input_shape, batch, in_y, in_x, in_channel)];
float filter_value =
filter_data[Offset(filter_shape, out_channel, filter_y,
filter_x, in_channel)];
output_data[Offset(output_shape, batch, out_y, out_x,
out_channel)] +=
input_value * filter_value;
}
}
}
}
}
}
}
}
if (bias_data) {
for (int batch = 0; batch < batches; ++batch) {
for (int out_y = 0; out_y < output_height; ++out_y) {
for (int out_x = 0; out_x < output_width; ++out_x) {
for (int out_channel = 0; out_channel < output_depth; ++out_channel) {
output_data[Offset(output_shape, batch, out_y, out_x,
out_channel)] += bias_data[out_channel];
}
}
}
}
}
}