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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009 Gael Guennebaud <gael.guennebaud@inria.fr>
// Modifications Copyright (C) 2022 Intel Corporation
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_TRIANGULAR_SOLVER_MATRIX_H
#define EIGEN_TRIANGULAR_SOLVER_MATRIX_H
// IWYU pragma: private
#include "../InternalHeaderCheck.h"
namespace Eigen {
namespace internal {
template <typename Scalar, typename Index, int Mode, bool Conjugate, int TriStorageOrder, int OtherInnerStride,
bool Specialized>
struct trsmKernelL {
// Generic Implementation of triangular solve for triangular matrix on left and multiple rhs.
// Handles non-packed matrices.
static void kernel(Index size, Index otherSize, const Scalar* _tri, Index triStride, Scalar* _other, Index otherIncr,
Index otherStride);
};
template <typename Scalar, typename Index, int Mode, bool Conjugate, int TriStorageOrder, int OtherInnerStride,
bool Specialized>
struct trsmKernelR {
// Generic Implementation of triangular solve for triangular matrix on right and multiple lhs.
// Handles non-packed matrices.
static void kernel(Index size, Index otherSize, const Scalar* _tri, Index triStride, Scalar* _other, Index otherIncr,
Index otherStride);
};
template <typename Scalar, typename Index, int Mode, bool Conjugate, int TriStorageOrder, int OtherInnerStride,
bool Specialized>
EIGEN_STRONG_INLINE void trsmKernelL<Scalar, Index, Mode, Conjugate, TriStorageOrder, OtherInnerStride,
Specialized>::kernel(Index size, Index otherSize, const Scalar* _tri,
Index triStride, Scalar* _other, Index otherIncr,
Index otherStride) {
typedef const_blas_data_mapper<Scalar, Index, TriStorageOrder> TriMapper;
typedef blas_data_mapper<Scalar, Index, ColMajor, Unaligned, OtherInnerStride> OtherMapper;
TriMapper tri(_tri, triStride);
OtherMapper other(_other, otherStride, otherIncr);
enum { IsLower = (Mode & Lower) == Lower };
conj_if<Conjugate> conj;
// tr solve
for (Index k = 0; k < size; ++k) {
// TODO write a small kernel handling this (can be shared with trsv)
Index i = IsLower ? k : -k - 1;
Index rs = size - k - 1; // remaining size
Index s = TriStorageOrder == RowMajor ? (IsLower ? 0 : i + 1) : IsLower ? i + 1 : i - rs;
Scalar a = (Mode & UnitDiag) ? Scalar(1) : Scalar(Scalar(1)/conj(tri(i,i)));
for (Index j = 0; j < otherSize; ++j) {
if (TriStorageOrder == RowMajor) {
Scalar b(0);
const Scalar* l = &tri(i, s);
typename OtherMapper::LinearMapper r = other.getLinearMapper(s, j);
for (Index i3 = 0; i3 < k; ++i3) b += conj(l[i3]) * r(i3);
other(i, j) = (other(i, j) - b) * a;
} else {
Scalar& otherij = other(i, j);
otherij *= a;
Scalar b = otherij;
typename OtherMapper::LinearMapper r = other.getLinearMapper(s, j);
typename TriMapper::LinearMapper l = tri.getLinearMapper(s, i);
for (Index i3 = 0; i3 < rs; ++i3) r(i3) -= b * conj(l(i3));
}
}
}
}
template <typename Scalar, typename Index, int Mode, bool Conjugate, int TriStorageOrder, int OtherInnerStride,
bool Specialized>
EIGEN_STRONG_INLINE void trsmKernelR<Scalar, Index, Mode, Conjugate, TriStorageOrder, OtherInnerStride,
Specialized>::kernel(Index size, Index otherSize, const Scalar* _tri,
Index triStride, Scalar* _other, Index otherIncr,
Index otherStride) {
typedef typename NumTraits<Scalar>::Real RealScalar;
typedef blas_data_mapper<Scalar, Index, ColMajor, Unaligned, OtherInnerStride> LhsMapper;
typedef const_blas_data_mapper<Scalar, Index, TriStorageOrder> RhsMapper;
LhsMapper lhs(_other, otherStride, otherIncr);
RhsMapper rhs(_tri, triStride);
enum { RhsStorageOrder = TriStorageOrder, IsLower = (Mode & Lower) == Lower };
conj_if<Conjugate> conj;
for (Index k = 0; k < size; ++k) {
Index j = IsLower ? size - k - 1 : k;
typename LhsMapper::LinearMapper r = lhs.getLinearMapper(0, j);
for (Index k3 = 0; k3 < k; ++k3) {
Scalar b = conj(rhs(IsLower ? j + 1 + k3 : k3, j));
typename LhsMapper::LinearMapper a = lhs.getLinearMapper(0, IsLower ? j + 1 + k3 : k3);
for (Index i = 0; i < otherSize; ++i) r(i) -= a(i) * b;
}
if ((Mode & UnitDiag) == 0) {
Scalar inv_rjj = RealScalar(1) / conj(rhs(j, j));
for (Index i = 0; i < otherSize; ++i) r(i) *= inv_rjj;
}
}
}
// if the rhs is row major, let's transpose the product
template <typename Scalar, typename Index, int Side, int Mode, bool Conjugate, int TriStorageOrder,
int OtherInnerStride>
struct triangular_solve_matrix<Scalar, Index, Side, Mode, Conjugate, TriStorageOrder, RowMajor, OtherInnerStride> {
static void run(Index size, Index cols, const Scalar* tri, Index triStride, Scalar* _other, Index otherIncr,
Index otherStride, level3_blocking<Scalar, Scalar>& blocking) {
triangular_solve_matrix<
Scalar, Index, Side == OnTheLeft ? OnTheRight : OnTheLeft, (Mode & UnitDiag) | ((Mode & Upper) ? Lower : Upper),
NumTraits<Scalar>::IsComplex && Conjugate, TriStorageOrder == RowMajor ? ColMajor : RowMajor, ColMajor,
OtherInnerStride>::run(size, cols, tri, triStride, _other, otherIncr, otherStride, blocking);
}
};
/* Optimized triangular solver with multiple right hand side and the triangular matrix on the left
*/
template <typename Scalar, typename Index, int Mode, bool Conjugate, int TriStorageOrder, int OtherInnerStride>
struct triangular_solve_matrix<Scalar, Index, OnTheLeft, Mode, Conjugate, TriStorageOrder, ColMajor, OtherInnerStride> {
static EIGEN_DONT_INLINE void run(Index size, Index otherSize, const Scalar* _tri, Index triStride, Scalar* _other,
Index otherIncr, Index otherStride, level3_blocking<Scalar, Scalar>& blocking);
};
template <typename Scalar, typename Index, int Mode, bool Conjugate, int TriStorageOrder, int OtherInnerStride>
EIGEN_DONT_INLINE void triangular_solve_matrix<Scalar, Index, OnTheLeft, Mode, Conjugate, TriStorageOrder, ColMajor,
OtherInnerStride>::run(Index size, Index otherSize, const Scalar* _tri,
Index triStride, Scalar* _other, Index otherIncr,
Index otherStride,
level3_blocking<Scalar, Scalar>& blocking) {
Index cols = otherSize;
std::ptrdiff_t l1, l2, l3;
manage_caching_sizes(GetAction, &l1, &l2, &l3);
#if defined(EIGEN_VECTORIZE_AVX512) && EIGEN_USE_AVX512_TRSM_L_KERNELS && EIGEN_ENABLE_AVX512_NOCOPY_TRSM_L_CUTOFFS
EIGEN_IF_CONSTEXPR(
(OtherInnerStride == 1 && (std::is_same<Scalar, float>::value || std::is_same<Scalar, double>::value))) {
// Very rough cutoffs to determine when to call trsm w/o packing
// For small problem sizes trsmKernel compiled with clang is generally faster.
// TODO: Investigate better heuristics for cutoffs.
double L2Cap = 0.5; // 50% of L2 size
if (size < avx512_trsm_cutoff<Scalar>(l2, cols, L2Cap)) {
trsmKernelL<Scalar, Index, Mode, Conjugate, TriStorageOrder, 1, /*Specialized=*/true>::kernel(
size, cols, _tri, triStride, _other, 1, otherStride);
return;
}
}
#endif
typedef const_blas_data_mapper<Scalar, Index, TriStorageOrder> TriMapper;
typedef blas_data_mapper<Scalar, Index, ColMajor, Unaligned, OtherInnerStride> OtherMapper;
TriMapper tri(_tri, triStride);
OtherMapper other(_other, otherStride, otherIncr);
typedef gebp_traits<Scalar, Scalar> Traits;
enum { SmallPanelWidth = plain_enum_max(Traits::mr, Traits::nr), IsLower = (Mode & Lower) == Lower };
Index kc = blocking.kc(); // cache block size along the K direction
Index mc = (std::min)(size, blocking.mc()); // cache block size along the M direction
std::size_t sizeA = kc * mc;
std::size_t sizeB = kc * cols;
ei_declare_aligned_stack_constructed_variable(Scalar, blockA, sizeA, blocking.blockA());
ei_declare_aligned_stack_constructed_variable(Scalar, blockB, sizeB, blocking.blockB());
gebp_kernel<Scalar, Scalar, Index, OtherMapper, Traits::mr, Traits::nr, Conjugate, false> gebp_kernel;
gemm_pack_lhs<Scalar, Index, TriMapper, Traits::mr, Traits::LhsProgress, typename Traits::LhsPacket4Packing,
TriStorageOrder>
pack_lhs;
gemm_pack_rhs<Scalar, Index, OtherMapper, Traits::nr, ColMajor, false, true> pack_rhs;
// the goal here is to subdivise the Rhs panels such that we keep some cache
// coherence when accessing the rhs elements
Index subcols = cols > 0 ? l2 / (4 * sizeof(Scalar) * std::max<Index>(otherStride, size)) : 0;
subcols = std::max<Index>((subcols / Traits::nr) * Traits::nr, Traits::nr);
for (Index k2 = IsLower ? 0 : size; IsLower ? k2 < size : k2 > 0; IsLower ? k2 += kc : k2 -= kc) {
const Index actual_kc = (std::min)(IsLower ? size - k2 : k2, kc);
// We have selected and packed a big horizontal panel R1 of rhs. Let B be the packed copy of this panel,
// and R2 the remaining part of rhs. The corresponding vertical panel of lhs is split into
// A11 (the triangular part) and A21 the remaining rectangular part.
// Then the high level algorithm is:
// - B = R1 => general block copy (done during the next step)
// - R1 = A11^-1 B => tricky part
// - update B from the new R1 => actually this has to be performed continuously during the above step
// - R2 -= A21 * B => GEPP
// The tricky part: compute R1 = A11^-1 B while updating B from R1
// The idea is to split A11 into multiple small vertical panels.
// Each panel can be split into a small triangular part T1k which is processed without optimization,
// and the remaining small part T2k which is processed using gebp with appropriate block strides
for (Index j2 = 0; j2 < cols; j2 += subcols) {
Index actual_cols = (std::min)(cols - j2, subcols);
// for each small vertical panels [T1k^T, T2k^T]^T of lhs
for (Index k1 = 0; k1 < actual_kc; k1 += SmallPanelWidth) {
Index actualPanelWidth = std::min<Index>(actual_kc - k1, SmallPanelWidth);
// tr solve
{
Index i = IsLower ? k2 + k1 : k2 - k1;
#if defined(EIGEN_VECTORIZE_AVX512) && EIGEN_USE_AVX512_TRSM_L_KERNELS
EIGEN_IF_CONSTEXPR(
(OtherInnerStride == 1 && (std::is_same<Scalar, float>::value || std::is_same<Scalar, double>::value))) {
i = IsLower ? k2 + k1 : k2 - k1 - actualPanelWidth;
}
#endif
trsmKernelL<Scalar, Index, Mode, Conjugate, TriStorageOrder, OtherInnerStride, /*Specialized=*/true>::kernel(
actualPanelWidth, actual_cols, _tri + i + (i)*triStride, triStride,
_other + i * OtherInnerStride + j2 * otherStride, otherIncr, otherStride);
}
Index lengthTarget = actual_kc - k1 - actualPanelWidth;
Index startBlock = IsLower ? k2 + k1 : k2 - k1 - actualPanelWidth;
Index blockBOffset = IsLower ? k1 : lengthTarget;
// update the respective rows of B from other
pack_rhs(blockB + actual_kc * j2, other.getSubMapper(startBlock, j2), actualPanelWidth, actual_cols, actual_kc,
blockBOffset);
// GEBP
if (lengthTarget > 0) {
Index startTarget = IsLower ? k2 + k1 + actualPanelWidth : k2 - actual_kc;
pack_lhs(blockA, tri.getSubMapper(startTarget, startBlock), actualPanelWidth, lengthTarget);
gebp_kernel(other.getSubMapper(startTarget, j2), blockA, blockB + actual_kc * j2, lengthTarget,
actualPanelWidth, actual_cols, Scalar(-1), actualPanelWidth, actual_kc, 0, blockBOffset);
}
}
}
// R2 -= A21 * B => GEPP
{
Index start = IsLower ? k2 + kc : 0;
Index end = IsLower ? size : k2 - kc;
for (Index i2 = start; i2 < end; i2 += mc) {
const Index actual_mc = (std::min)(mc, end - i2);
if (actual_mc > 0) {
pack_lhs(blockA, tri.getSubMapper(i2, IsLower ? k2 : k2 - kc), actual_kc, actual_mc);
gebp_kernel(other.getSubMapper(i2, 0), blockA, blockB, actual_mc, actual_kc, cols, Scalar(-1), -1, -1, 0, 0);
}
}
}
}
}
/* Optimized triangular solver with multiple left hand sides and the triangular matrix on the right
*/
template <typename Scalar, typename Index, int Mode, bool Conjugate, int TriStorageOrder, int OtherInnerStride>
struct triangular_solve_matrix<Scalar, Index, OnTheRight, Mode, Conjugate, TriStorageOrder, ColMajor,
OtherInnerStride> {
static EIGEN_DONT_INLINE void run(Index size, Index otherSize, const Scalar* _tri, Index triStride, Scalar* _other,
Index otherIncr, Index otherStride, level3_blocking<Scalar, Scalar>& blocking);
};
template <typename Scalar, typename Index, int Mode, bool Conjugate, int TriStorageOrder, int OtherInnerStride>
EIGEN_DONT_INLINE void triangular_solve_matrix<Scalar, Index, OnTheRight, Mode, Conjugate, TriStorageOrder, ColMajor,
OtherInnerStride>::run(Index size, Index otherSize, const Scalar* _tri,
Index triStride, Scalar* _other, Index otherIncr,
Index otherStride,
level3_blocking<Scalar, Scalar>& blocking) {
Index rows = otherSize;
#if defined(EIGEN_VECTORIZE_AVX512) && EIGEN_USE_AVX512_TRSM_R_KERNELS && EIGEN_ENABLE_AVX512_NOCOPY_TRSM_R_CUTOFFS
EIGEN_IF_CONSTEXPR(
(OtherInnerStride == 1 && (std::is_same<Scalar, float>::value || std::is_same<Scalar, double>::value))) {
// TODO: Investigate better heuristics for cutoffs.
std::ptrdiff_t l1, l2, l3;
manage_caching_sizes(GetAction, &l1, &l2, &l3);
double L2Cap = 0.5; // 50% of L2 size
if (size < avx512_trsm_cutoff<Scalar>(l2, rows, L2Cap)) {
trsmKernelR<Scalar, Index, Mode, Conjugate, TriStorageOrder, OtherInnerStride, /*Specialized=*/true>::kernel(
size, rows, _tri, triStride, _other, 1, otherStride);
return;
}
}
#endif
typedef blas_data_mapper<Scalar, Index, ColMajor, Unaligned, OtherInnerStride> LhsMapper;
typedef const_blas_data_mapper<Scalar, Index, TriStorageOrder> RhsMapper;
LhsMapper lhs(_other, otherStride, otherIncr);
RhsMapper rhs(_tri, triStride);
typedef gebp_traits<Scalar, Scalar> Traits;
enum {
RhsStorageOrder = TriStorageOrder,
SmallPanelWidth = plain_enum_max(Traits::mr, Traits::nr),
IsLower = (Mode & Lower) == Lower
};
Index kc = blocking.kc(); // cache block size along the K direction
Index mc = (std::min)(rows, blocking.mc()); // cache block size along the M direction
std::size_t sizeA = kc * mc;
std::size_t sizeB = kc * size;
ei_declare_aligned_stack_constructed_variable(Scalar, blockA, sizeA, blocking.blockA());
ei_declare_aligned_stack_constructed_variable(Scalar, blockB, sizeB, blocking.blockB());
gebp_kernel<Scalar, Scalar, Index, LhsMapper, Traits::mr, Traits::nr, false, Conjugate> gebp_kernel;
gemm_pack_rhs<Scalar, Index, RhsMapper, Traits::nr, RhsStorageOrder> pack_rhs;
gemm_pack_rhs<Scalar, Index, RhsMapper, Traits::nr, RhsStorageOrder, false, true> pack_rhs_panel;
gemm_pack_lhs<Scalar, Index, LhsMapper, Traits::mr, Traits::LhsProgress, typename Traits::LhsPacket4Packing, ColMajor,
false, true>
pack_lhs_panel;
for (Index k2 = IsLower ? size : 0; IsLower ? k2 > 0 : k2 < size; IsLower ? k2 -= kc : k2 += kc) {
const Index actual_kc = (std::min)(IsLower ? k2 : size - k2, kc);
Index actual_k2 = IsLower ? k2 - actual_kc : k2;
Index startPanel = IsLower ? 0 : k2 + actual_kc;
Index rs = IsLower ? actual_k2 : size - actual_k2 - actual_kc;
Scalar* geb = blockB + actual_kc * actual_kc;
if (rs > 0) pack_rhs(geb, rhs.getSubMapper(actual_k2, startPanel), actual_kc, rs);
// triangular packing (we only pack the panels off the diagonal,
// neglecting the blocks overlapping the diagonal
{
for (Index j2 = 0; j2 < actual_kc; j2 += SmallPanelWidth) {
Index actualPanelWidth = std::min<Index>(actual_kc - j2, SmallPanelWidth);
Index actual_j2 = actual_k2 + j2;
Index panelOffset = IsLower ? j2 + actualPanelWidth : 0;
Index panelLength = IsLower ? actual_kc - j2 - actualPanelWidth : j2;
if (panelLength > 0)
pack_rhs_panel(blockB + j2 * actual_kc, rhs.getSubMapper(actual_k2 + panelOffset, actual_j2), panelLength,
actualPanelWidth, actual_kc, panelOffset);
}
}
for (Index i2 = 0; i2 < rows; i2 += mc) {
const Index actual_mc = (std::min)(mc, rows - i2);
// triangular solver kernel
{
// for each small block of the diagonal (=> vertical panels of rhs)
for (Index j2 = IsLower ? (actual_kc - ((actual_kc % SmallPanelWidth) ? Index(actual_kc % SmallPanelWidth)
: Index(SmallPanelWidth)))
: 0;
IsLower ? j2 >= 0 : j2 < actual_kc; IsLower ? j2 -= SmallPanelWidth : j2 += SmallPanelWidth) {
Index actualPanelWidth = std::min<Index>(actual_kc - j2, SmallPanelWidth);
Index absolute_j2 = actual_k2 + j2;
Index panelOffset = IsLower ? j2 + actualPanelWidth : 0;
Index panelLength = IsLower ? actual_kc - j2 - actualPanelWidth : j2;
// GEBP
if (panelLength > 0) {
gebp_kernel(lhs.getSubMapper(i2, absolute_j2), blockA, blockB + j2 * actual_kc, actual_mc, panelLength,
actualPanelWidth, Scalar(-1), actual_kc, actual_kc, // strides
panelOffset, panelOffset); // offsets
}
{
// unblocked triangular solve
trsmKernelR<Scalar, Index, Mode, Conjugate, TriStorageOrder, OtherInnerStride,
/*Specialized=*/true>::kernel(actualPanelWidth, actual_mc,
_tri + absolute_j2 + absolute_j2 * triStride, triStride,
_other + i2 * OtherInnerStride + absolute_j2 * otherStride,
otherIncr, otherStride);
}
// pack the just computed part of lhs to A
pack_lhs_panel(blockA, lhs.getSubMapper(i2, absolute_j2), actualPanelWidth, actual_mc, actual_kc, j2);
}
}
if (rs > 0)
gebp_kernel(lhs.getSubMapper(i2, startPanel), blockA, geb, actual_mc, actual_kc, rs, Scalar(-1), -1, -1, 0, 0);
}
}
}
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_TRIANGULAR_SOLVER_MATRIX_H