Halide::Func convolution_layer(Halide::Func input, Halide::Func weights,
Halide::Func bias, int filter_size, int input_layers, int pool_size) {
// Convolution
Halide::Func convolution;
Halide::Var x, y, z, w;
Halide::RDom r(0, filter_size, 0, filter_size, 0, input_layers);
convolution(x, y, z, w) = 0.0f;
convolution(x, y, z, w) += weights(r.x, r.y, r.z, z) *
input(x + r.x, y + r.y, r.z, w);
// Max pool
Halide::Func subsample;
Halide::RDom s(0, pool_size, 0, pool_size);
subsample(x, y, z, w) = 0.0f;
subsample(x, y, z, w) = Halide::max(convolution(pool_size * x + s.x,
pool_size * y + s.y, z, w), subsample(x, y, z, w));
// Non-linear bias
Halide::Func biased;
biased(x, y, z, w) = tanh(subsample(x, y, z, w) + bias(z, 0));
Halide::Var x_inner, x_outer, y_inner, y_outer;
biased.parallel(w);
biased.tile(x, y, x_outer, y_outer, x_inner, y_inner, VECTORS, 2);
biased.vectorize(x_inner);
biased.unroll(y_inner);
return biased;
}
int resize_with_halide()
{
Halide::ImageParam input {Halide::type_of<uint8_t>(), 3};
//_/_/_/ load a source image and repeat its edges
Halide::Func src_image {};
src_image = Halide::BoundaryConditions::repeat_edge(input);
//_/_/_/ describe algorithm
Halide::Param<float> src_rows {};
Halide::Param<float> src_cols {};
Halide::Param<float> dst_rows {};
Halide::Param<float> dst_cols {};
// const float sc = 500.0f/4999;//static_cast<float>(src_cols.get()) / dst_cols.get();
// const float sr = 350.0f/3499;//static_cast<float>(src_rows.get()) / dst_rows.get();
const auto sc = src_cols / dst_cols;
const auto sr = src_rows / dst_rows;
Halide::Var i {};
Halide::Var j {};
Halide::Var c {};
auto fj = j * sr;
auto cj0 = Halide::cast<int>(fj);
auto cj1 = cj0 + 1;
auto dj = fj - cj0;
auto fi = i * sc;
auto ci0 = Halide::cast<int>(fi);
auto ci1 = ci0 + 1;
auto di = fi - ci0;
const auto c0 = (1.0f - dj) * (1.0f - di);
const auto c1 = (1.0f - dj) * di;
const auto c2 = dj * (1.0f - di);
const auto c3 = dj * di;
const auto& src_pixel0 = src_image(ci0, cj0, c);
const auto& src_pixel1 = src_image(ci1, cj0, c);
const auto& src_pixel2 = src_image(ci0, cj1, c);
const auto& src_pixel3 = src_image(ci1, cj1, c);
Halide::Func resize {};
resize(i, j, c) = Halide::saturating_cast<uint8_t>(c0 * src_pixel0 + c1 * src_pixel1 + c2 * src_pixel2 + c3 * src_pixel3);
//_/_/_/ describe scheduling
Halide::Var i_inner, j_inner;
auto x_vector_size = 64;
resize.compute_root();
resize.tile(i, j, i_inner, j_inner, x_vector_size, 4).vectorize(i_inner, 16).parallel(j);
//_/_/_/ save a static library
const auto path = "/Users/kumada/Projects/cct_blog/halide/sample_4/sample_4/resize";
resize.compile_to_static_library(
path,
{input, src_rows, src_cols, dst_rows, dst_cols},
"resize");
return 1;
}