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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "lib/jxl/convolve.h"
#undef HWY_TARGET_INCLUDE
#define HWY_TARGET_INCLUDE "lib/jxl/convolve_symmetric3.cc"
#include <hwy/foreach_target.h>
#include <hwy/highway.h>
#include "lib/jxl/convolve-inl.h"
HWY_BEFORE_NAMESPACE();
namespace jxl {
namespace HWY_NAMESPACE {
// These templates are not found via ADL.
using hwy::HWY_NAMESPACE::Add;
using hwy::HWY_NAMESPACE::Mul;
using hwy::HWY_NAMESPACE::MulAdd;
using hwy::HWY_NAMESPACE::Vec;
template <class WrapY, class V>
static V WeightedSum(const ImageF& in, const WrapY wrap_y, const size_t ix,
const int64_t iy, const size_t ysize, const V wx0,
const V wx1, const V wx2) {
const HWY_FULL(float) d;
const float* JXL_RESTRICT center = in.ConstRow(wrap_y(iy, ysize)) + ix;
const auto in_m2 = LoadU(d, center - 2);
const auto in_p2 = LoadU(d, center + 2);
const auto in_m1 = LoadU(d, center - 1);
const auto in_p1 = LoadU(d, center + 1);
const auto in_00 = Load(d, center);
const auto sum_2 = Mul(wx2, Add(in_m2, in_p2));
const auto sum_1 = Mul(wx1, Add(in_m1, in_p1));
const auto sum_0 = Mul(wx0, in_00);
return Add(sum_2, Add(sum_1, sum_0));
}
// 3x3 convolution by symmetric kernel with a single scan through the input.
class Symmetric3Strategy {
using D = HWY_CAPPED(float, 16);
using V = Vec<D>;
public:
static constexpr int64_t kRadius = 1;
// Only accesses pixels in [0, xsize).
template <size_t kSizeModN, class WrapRow>
static JXL_MAYBE_INLINE void ConvolveRow(
const float* const JXL_RESTRICT row_m, const size_t xsize,
const int64_t stride, const WrapRow& wrap_row,
const WeightsSymmetric3& weights, float* const JXL_RESTRICT row_out) {
const D d;
// t, m, b = top, middle, bottom row;
const float* const JXL_RESTRICT row_t = wrap_row(row_m - stride, stride);
const float* const JXL_RESTRICT row_b = wrap_row(row_m + stride, stride);
// Must load in advance - compiler doesn't understand LoadDup128 and
// schedules them too late.
const V w0 = LoadDup128(d, weights.c);
const V w1 = LoadDup128(d, weights.r);
const V w2 = LoadDup128(d, weights.d);
// l, c, r = left, center, right. Leftmost vector: need FirstL1.
{
const V tc = LoadU(d, row_t + 0);
const V mc = LoadU(d, row_m + 0);
const V bc = LoadU(d, row_b + 0);
const V tl = Neighbors::FirstL1(tc);
const V tr = LoadU(d, row_t + 0 + 1);
const V ml = Neighbors::FirstL1(mc);
const V mr = LoadU(d, row_m + 0 + 1);
const V bl = Neighbors::FirstL1(bc);
const V br = LoadU(d, row_b + 0 + 1);
const V conv =
WeightedSum(tl, tc, tr, ml, mc, mr, bl, bc, br, w0, w1, w2);
Store(conv, d, row_out + 0);
}
// Loop as long as we can load enough new values:
const size_t N = Lanes(d);
size_t x = N;
for (; x + N + kRadius <= xsize; x += N) {
const auto conv = ConvolveValid(row_t, row_m, row_b, x, w0, w1, w2);
Store(conv, d, row_out + x);
}
// For final (partial) vector:
const V tc = LoadU(d, row_t + x);
const V mc = LoadU(d, row_m + x);
const V bc = LoadU(d, row_b + x);
V tr, mr, br;
#if HWY_TARGET == HWY_SCALAR
tr = tc; // Single-lane => mirrored right neighbor = center value.
mr = mc;
br = bc;
#else
if (kSizeModN == 0) {
// The above loop didn't handle the last vector because it needs an
// additional right neighbor (generated via mirroring).
auto mirror = SetTableIndices(d, MirrorLanes(N - 1));
tr = TableLookupLanes(tc, mirror);
mr = TableLookupLanes(mc, mirror);
br = TableLookupLanes(bc, mirror);
} else {
auto mirror = SetTableIndices(d, MirrorLanes((xsize % N) - 1));
// Loads last valid value into uppermost lane and mirrors.
tr = TableLookupLanes(LoadU(d, row_t + xsize - N), mirror);
mr = TableLookupLanes(LoadU(d, row_m + xsize - N), mirror);
br = TableLookupLanes(LoadU(d, row_b + xsize - N), mirror);
}
#endif
const V tl = LoadU(d, row_t + x - 1);
const V ml = LoadU(d, row_m + x - 1);
const V bl = LoadU(d, row_b + x - 1);
const V conv = WeightedSum(tl, tc, tr, ml, mc, mr, bl, bc, br, w0, w1, w2);
Store(conv, d, row_out + x);
}
private:
// Returns sum{x_i * w_i}.
template <class V>
static JXL_MAYBE_INLINE V WeightedSum(const V tl, const V tc, const V tr,
const V ml, const V mc, const V mr,
const V bl, const V bc, const V br,
const V w0, const V w1, const V w2) {
const V sum_tb = Add(tc, bc);
// Faster than 5 mul + 4 FMA.
const V mul0 = Mul(mc, w0);
const V sum_lr = Add(ml, mr);
const V x1 = Add(sum_tb, sum_lr);
const V mul1 = MulAdd(x1, w1, mul0);
const V sum_t2 = Add(tl, tr);
const V sum_b2 = Add(bl, br);
const V x2 = Add(sum_t2, sum_b2);
const V mul2 = MulAdd(x2, w2, mul1);
return mul2;
}
static JXL_MAYBE_INLINE V ConvolveValid(const float* JXL_RESTRICT row_t,
const float* JXL_RESTRICT row_m,
const float* JXL_RESTRICT row_b,
const int64_t x, const V w0,
const V w1, const V w2) {
const D d;
const V tc = LoadU(d, row_t + x);
const V mc = LoadU(d, row_m + x);
const V bc = LoadU(d, row_b + x);
const V tl = LoadU(d, row_t + x - 1);
const V tr = LoadU(d, row_t + x + 1);
const V ml = LoadU(d, row_m + x - 1);
const V mr = LoadU(d, row_m + x + 1);
const V bl = LoadU(d, row_b + x - 1);
const V br = LoadU(d, row_b + x + 1);
return WeightedSum(tl, tc, tr, ml, mc, mr, bl, bc, br, w0, w1, w2);
}
};
void Symmetric3(const ImageF& in, const Rect& rect,
const WeightsSymmetric3& weights, ThreadPool* pool,
ImageF* out) {
using Conv = ConvolveT<Symmetric3Strategy>;
if (rect.xsize() >= Conv::MinWidth()) {
return Conv::Run(in, rect, weights, pool, out);
}
return SlowSymmetric3(in, rect, weights, pool, out);
}
// NOLINTNEXTLINE(google-readability-namespace-comments)
} // namespace HWY_NAMESPACE
} // namespace jxl
HWY_AFTER_NAMESPACE();
#if HWY_ONCE
namespace jxl {
HWY_EXPORT(Symmetric3);
void Symmetric3(const ImageF& in, const Rect& rect,
const WeightsSymmetric3& weights, ThreadPool* pool,
ImageF* out) {
return HWY_DYNAMIC_DISPATCH(Symmetric3)(in, rect, weights, pool, out);
}
} // namespace jxl
#endif // HWY_ONCE
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