perf(shell): route local products through MKL and reduce Hessian storage work

This commit is contained in:
KOKO\Mimi
2026-10-14 18:07:16 +09:00
parent 8c7c41729e
commit f9e0df66dc
9 changed files with 758 additions and 179 deletions
+12 -23
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@@ -8,6 +8,7 @@
#include <utility>
#include "fesa/model/model_types.h"
#include "math/dense_blas_internal.h"
namespace fesa {
@@ -223,28 +224,18 @@ Matrix ScaledMatrix(const Matrix& source, double factor) {
return result;
}
/// @brief Lifts a local matrix by a deterministic serial congruence product.
/// @note The loop and accumulation order are part of reproducible stiffness.
/// @brief Lifts a local matrix through MKL and mirrors the upper triangle.
Matrix Congruence(const Matrix& local, const Matrix& transformation) {
if (local.Rows() != local.Columns() ||
local.Rows() != transformation.Rows()) {
throw std::invalid_argument{
"MITC4 congruence dimensions are incompatible."};
}
Matrix result{transformation.Columns(), transformation.Columns()};
Matrix result = dense_blas_internal::MultiplyTransposeLeft(
transformation, local.Multiply(transformation));
for (std::size_t row = 0U; row < result.Rows(); ++row) {
for (std::size_t column = row; column < result.Columns(); ++column) {
double value = 0.0;
for (std::size_t local_row = 0U; local_row < local.Rows(); ++local_row) {
for (std::size_t local_column = 0U; local_column < local.Columns();
++local_column) {
value += transformation(local_row, row) *
local(local_row, local_column) *
transformation(local_column, column);
}
}
result(row, column) = value;
result(column, row) = value;
result(column, row) = result(row, column);
}
}
return result;
@@ -611,7 +602,8 @@ Matrix Mitc4Shell::TransverseShearSectionMatrix() const {
return result;
}
Result<Mitc4Stiffness> Mitc4Shell::Stiffness() const {
Result<Mitc4Stiffness> Mitc4Shell::Stiffness() const try {
const dense_blas_internal::ScopedLocalDenseThreads local_threads{};
const Matrix constitutive = MaterialConstitutive5();
const Matrix tying_samples = CovariantTyingShearSamples20();
Matrix physical_local{kPhysicalDofCount, kPhysicalDofCount};
@@ -627,17 +619,12 @@ Result<Mitc4Stiffness> Mitc4Shell::Stiffness() const {
const Matrix strain = StrainDisplacement(
point.natural_coordinates[0], point.natural_coordinates[1],
point.natural_coordinates[2], &tying_samples);
const Matrix integrand = dense_blas_internal::MultiplyTransposeLeft(
strain, constitutive.Multiply(strain));
for (std::size_t row = 0U; row < kPhysicalDofCount; ++row) {
for (std::size_t column = row; column < kPhysicalDofCount; ++column) {
double integrand = 0.0;
for (std::size_t first = 0U; first < 5U; ++first) {
for (std::size_t second = 0U; second < 5U; ++second) {
integrand += strain(first, row) * constitutive(first, second) *
strain(second, column);
}
}
const double contribution =
integrand * geometry.jacobian * point.weight;
integrand(row, column) * geometry.jacobian * point.weight;
physical_local(row, column) += contribution;
if (row != column) {
physical_local(column, row) += contribution;
@@ -714,6 +701,8 @@ Result<Mitc4Stiffness> Mitc4Shell::Stiffness() const {
Mitc4Stiffness{std::move(physical_local), std::move(physical_global),
std::move(drilling_global), std::move(stabilized_global),
drilling_stiffness});
} catch (const std::exception& error) {
return StiffnessFailure(source_location_, identity_, error.what());
}
Result<Mitc4Mass> Mitc4Shell::Mass(const double density) const {
+92 -73
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@@ -4,11 +4,13 @@
#include <array>
#include <cmath>
#include <cstddef>
#include <exception>
#include <limits>
#include <string>
#include <utility>
#include "fesa/elements/finite_rotation.h"
#include "math/dense_blas_internal.h"
namespace fesa {
namespace {
@@ -35,6 +37,16 @@ class InertiaSum {
double correction_ = 0.0;
};
/// @brief Contracts two nodal 6-by-3 coefficient blocks through dense MKL.
/// @note Nonfinite coefficients remain failures of the final inertia gate.
void DotBlocks(const std::array<double, 18U>& left,
const std::array<double, 18U>& right,
std::array<double, 36U>& result) {
if (!dense_blas_internal::MultiplyTransposeRight(
left.data(), 6U, right.data(), 6U, 3U, result.data()))
result.fill(std::numeric_limits<double>::quiet_NaN());
}
Vector3 WeightedSum(const std::array<double, kNodes>& weights,
const std::array<Vector3, kNodes>& values) {
Vector3 result{};
@@ -442,12 +454,11 @@ Status CheckPhysicalMass(const Matrix& mass,
}
double gram_error = 0.0;
double orthogonality_error = 0.0;
const Matrix gram =
dense_blas_internal::MultiplyTransposeLeft(complement, complement);
for (std::size_t row = 0U; row < kPhysical; ++row) {
for (std::size_t column = 0U; column < kPhysical; ++column) {
double entry = row == column ? -1.0 : 0.0;
for (std::size_t inner = 0U; inner < kDofs; ++inner) {
entry += complement(inner, row) * complement(inner, column);
}
const double entry = gram(row, column) - (row == column ? 1.0 : 0.0);
gram_error = std::hypot(gram_error, entry);
}
for (std::size_t node = 0U; node < kNodes; ++node) {
@@ -472,55 +483,42 @@ Status CheckPhysicalMass(const Matrix& mass,
return fail("invalid-nonlinear-inertia-null",
"Scaled mass symmetry and analytic null identities failed.");
}
Matrix block{kPhysical, kPhysical};
Matrix mass_complement{kDofs, kPhysical};
for (std::size_t row = 0U; row < kDofs; ++row) {
for (std::size_t column = 0U; column < kPhysical; ++column) {
for (std::size_t inner = 0U; inner < kDofs; ++inner) {
mass_complement(row, column) +=
scaled(row, inner) * complement(inner, column);
}
}
}
const Matrix mass_complement = scaled.Multiply(complement);
const Matrix block =
dense_blas_internal::MultiplyTransposeLeft(complement, mass_complement);
double block_norm = 0.0;
for (std::size_t row = 0U; row < kPhysical; ++row) {
double row_sum = 0.0;
for (std::size_t column = 0U; column < kPhysical; ++column) {
for (std::size_t inner = 0U; inner < kDofs; ++inner) {
block(row, column) +=
complement(inner, row) * mass_complement(inner, column);
}
row_sum += std::abs(block(row, column));
}
block_norm = std::max(block_norm, row_sum);
}
Matrix lower{kPhysical, kPhysical};
for (std::size_t row = 0U; row < kPhysical; ++row) {
for (std::size_t column = 0U; column <= row; ++column) {
double entry = block(row, column);
for (std::size_t inner = 0U; inner < column; ++inner) {
entry -= lower(row, inner) * lower(column, inner);
}
if (!std::isfinite(entry) || (row == column && !(entry > 0.0))) {
return fail(
"invalid-nonlinear-inertia-positive-mass",
"Physical mass requires strictly positive Cholesky pivots.");
}
lower(row, column) =
row == column ? std::sqrt(entry) : entry / lower(column, column);
}
Matrix inverse_lower{kPhysical, kPhysical};
auto factor_failure = dense_blas_internal::CholeskyFailure::kNone;
if (!dense_blas_internal::CholeskyLowerAndInverse(block, lower, inverse_lower,
&factor_failure)) {
if (factor_failure == dense_blas_internal::CholeskyFailure::kInverse)
return fail(
"ill-conditioned-nonlinear-inertia-positive-mass",
"Physical mass reciprocal infinity condition is below 2^-32.");
return fail("invalid-nonlinear-inertia-positive-mass",
"Physical mass requires strictly positive Cholesky pivots.");
}
std::array<double, kPhysical> inverse_row_sums{};
double reconstruction_error = 0.0;
double block_frobenius = 0.0;
Matrix transpose{kPhysical, kPhysical};
for (std::size_t row = 0U; row < kPhysical; ++row)
for (std::size_t column = 0U; column < kPhysical; ++column)
transpose(row, column) = lower(column, row);
const Matrix reconstructed = lower.Multiply(transpose);
for (std::size_t row = 0U; row < kPhysical; ++row) {
for (std::size_t column = 0U; column < kPhysical; ++column) {
double reconstructed = 0.0;
for (std::size_t inner = 0U; inner <= std::min(row, column); ++inner) {
reconstructed += lower(row, inner) * lower(column, inner);
}
reconstruction_error =
std::hypot(reconstruction_error, reconstructed - block(row, column));
std::hypot(reconstruction_error,
reconstructed(row, column) - block(row, column));
block_frobenius = std::hypot(block_frobenius, block(row, column));
}
}
@@ -528,25 +526,11 @@ Status CheckPhysicalMass(const Matrix& mass,
return fail("invalid-nonlinear-inertia-positive-mass",
"Physical mass Cholesky reconstruction failed.");
}
for (std::size_t column = 0U; column < kPhysical; ++column) {
std::array<double, kPhysical> solution{};
for (std::size_t row = 0U; row < kPhysical; ++row) {
double rhs = row == column ? 1.0 : 0.0;
for (std::size_t inner = 0U; inner < row; ++inner) {
rhs -= lower(row, inner) * solution[inner];
}
solution[row] = rhs / lower(row, row);
}
for (std::size_t reverse = kPhysical; reverse > 0U; --reverse) {
const std::size_t row = reverse - 1U;
double rhs = solution[row];
for (std::size_t inner = row + 1U; inner < kPhysical; ++inner) {
rhs -= lower(inner, row) * solution[inner];
}
solution[row] = rhs / lower(row, row);
inverse_row_sums[row] += std::abs(solution[row]);
}
}
const Matrix inverse =
dense_blas_internal::MultiplyTransposeLeft(inverse_lower, inverse_lower);
for (std::size_t column = 0U; column < kPhysical; ++column)
for (std::size_t row = 0U; row < kPhysical; ++row)
inverse_row_sums[row] += std::abs(inverse(row, column));
const double inverse_norm =
*std::max_element(inverse_row_sums.begin(), inverse_row_sums.end());
const double reciprocal_condition = 1.0 / block_norm / inverse_norm;
@@ -712,6 +696,7 @@ Result<NonlinearMitc4Inertia> NonlinearMitc4Inertia::Create(
Result<NonlinearMitc4InertiaEvaluation> NonlinearMitc4Inertia::Evaluate(
const NonlinearMitc4TrialDofs& trial, const Vector& velocity,
const Vector& acceleration) const {
const dense_blas_internal::ScopedLocalDenseThreads local_threads{};
if (velocity.Size() != kDofs || acceleration.Size() != kDofs ||
!IsFinite(velocity) || !IsFinite(acceleration)) {
return Failure<NonlinearMitc4InertiaEvaluation>(
@@ -899,6 +884,42 @@ Result<NonlinearMitc4InertiaEvaluation> NonlinearMitc4Inertia::Evaluate(
result.momentum_rate_scale += scale * acceleration_point.Norm();
result.angular_momentum_rate_scale +=
scale * position.Cross(acceleration_point).Norm();
std::array<double, 18U> h_block;
std::array<double, 18U> velocity_block;
std::array<double, 18U> position_block;
for (std::size_t local = 0U; local < 6U; ++local) {
const auto field = 6U * mass_node + local;
for (std::size_t axis = 0U; axis < 3U; ++axis) {
h_block[3U * local + axis] = h[field][axis];
velocity_block[3U * local + axis] =
velocity_derivative[field][axis];
position_block[3U * local + axis] =
position_derivative[field][axis];
}
}
std::array<double, 36U> mass_block;
std::array<double, 36U> velocity_product;
std::array<double, 36U> position_product;
DotBlocks(h_block, h_block, mass_block);
DotBlocks(h_block, velocity_block, velocity_product);
DotBlocks(h_block, position_block, position_product);
std::array<std::array<double, 36U>, 3U> mass_variation;
for (std::size_t direction = 0U; direction < 3U; ++direction) {
std::array<double, 18U> derivative_block;
for (std::size_t local = 0U; local < 6U; ++local) {
const Vector3 derivative =
local < 3U ? Vector3{}
: z * rotations[mass_node]
.director_second[local - 3U][direction];
for (std::size_t axis = 0U; axis < 3U; ++axis)
derivative_block[3U * local + axis] = derivative[axis];
}
std::array<double, 36U> reverse;
DotBlocks(derivative_block, h_block, mass_variation[direction]);
DotBlocks(h_block, derivative_block, reverse);
for (std::size_t index = 0U; index < 36U; ++index)
mass_variation[direction][index] += reverse[index];
}
for (std::size_t row = 6U * mass_node; row < 6U * (mass_node + 1U);
++row) {
// Keep c independent of a; subtracting M*a destroys small c values.
@@ -906,10 +927,11 @@ Result<NonlinearMitc4InertiaEvaluation> NonlinearMitc4Inertia::Evaluate(
scale * h[row].Dot(convective_point);
for (std::size_t column = 6U * mass_node;
column < 6U * (mass_node + 1U); ++column) {
result.mass(row, column) += scale * h[row].Dot(h[column]);
const auto local_index = 6U * (row % 6U) + column % 6U;
result.mass(row, column) += scale * mass_block[local_index];
result.velocity_tangent(row, column) +=
scale * h[row].Dot(velocity_derivative[column]);
double position_entry = h[row].Dot(position_derivative[column]);
scale * velocity_product[local_index];
double position_entry = position_product[local_index];
if (row / 6U == column / 6U && row % 6U >= 3U &&
column % 6U >= 3U) {
const std::size_t node = row / 6U;
@@ -922,20 +944,10 @@ Result<NonlinearMitc4InertiaEvaluation> NonlinearMitc4Inertia::Evaluate(
result.position_tangent(row, column) += scale * position_entry;
if (column % 6U >= 3U) {
const auto direction = column % 6U - 3U;
const Vector3 dh_row =
row % 6U < 3U
? Vector3{}
: z * rotations[mass_node]
.director_second[row % 6U - 3U][direction];
for (std::size_t local = 0U; local < 6U; ++local) {
const auto field = 6U * mass_node + local;
const Vector3 dh_field =
local < 3U
? Vector3{}
: z * rotations[mass_node]
.director_second[local - 3U][direction];
mass_derivative[mass_node][direction][row % 6U][local] +=
scale * (dh_row.Dot(h[field]) + h[row].Dot(dh_field));
scale *
mass_variation[direction][6U * (row % 6U) + local];
}
}
}
@@ -1004,8 +1016,15 @@ Result<NonlinearMitc4InertiaEvaluation> NonlinearMitc4Inertia::Evaluate(
"invalid-nonlinear-inertia-evaluation", source_location_, identity_,
"Nonlinear MITC4 inertia evaluation must remain finite.");
}
const Status physical_mass = CheckPhysicalMass(result.mass, nulls, length,
source_location_, identity_);
Status physical_mass = Status::Ok();
try {
physical_mass = CheckPhysicalMass(result.mass, nulls, length,
source_location_, identity_);
} catch (const std::exception& error) {
return Failure<NonlinearMitc4InertiaEvaluation>(
"invalid-nonlinear-inertia-positive-mass", source_location_, identity_,
error.what());
}
if (!physical_mass.IsOk()) {
return Result<NonlinearMitc4InertiaEvaluation>::Failure(physical_mass);
}
+104 -23
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@@ -10,6 +10,7 @@
#include <utility>
#include "fesa/elements/finite_rotation.h"
#include "math/dense_blas_internal.h"
namespace fesa {
namespace {
@@ -394,22 +395,63 @@ constexpr std::size_t kHessianSize = kGlobalDofCount * kGlobalDofCount;
/// @brief Carries exact first and second trial-coordinate variations.
class Hessian {
public:
Hessian() : values_{std::make_shared<std::array<double, kHessianSize>>()} {}
Hessian() = default;
double& operator[](const std::size_t index) { return (*values_)[index]; }
double& operator[](const std::size_t index) { return Data()[index]; }
const double& operator[](const std::size_t index) const {
return (*values_)[index];
return Storage()[index];
}
auto begin() const { return values_->begin(); }
auto begin() const { return Storage().begin(); }
auto end() const { return values_->end(); }
auto end() const { return Storage().end(); }
double* Data() {
if (!values_) {
values_ = std::make_shared<Values>();
values_->entries.fill(0.0);
}
return values_->entries.data();
}
const double* ReadData() const { return Storage().data(); }
/// @brief Gets fresh output storage without redundant zero initialization.
/// @note Only fresh operator results use this pointer; all 576 entries must
/// be written before any read or copy of the result.
double* OverwriteData() {
if (!values_) values_ = std::make_shared<Values>();
return values_->entries.data();
}
private:
std::shared_ptr<std::array<double, kHessianSize>> values_;
struct Values {
// User-provided construction leaves entries uninitialized for a complete
// output overwrite while make_shared retains the single allocation.
Values() noexcept {}
std::array<double, kHessianSize> entries;
};
const std::array<double, kHessianSize>& Storage() const {
// Constants borrow only this immutable zero. Mutable coefficients retain
// the existing shared ownership; no trial-dependent cache is introduced.
static const std::array<double, kHessianSize> kZero{};
return values_ ? values_->entries : kZero;
}
std::shared_ptr<Values> values_;
};
/// @brief Forms an ordinary derivative outer product without a Matrix copy.
/// @note Rejected nonfinite operands propagate to the existing Jet finite gate.
void Outer(const std::array<double, kGlobalDofCount>& left,
const std::array<double, kGlobalDofCount>& right, double* result) {
if (!dense_blas_internal::OuterProduct(left.data(), left.size(), right.data(),
right.size(), result))
std::fill_n(result, kHessianSize, std::numeric_limits<double>::quiet_NaN());
}
/// @brief Carries exact first and second trial-coordinate variations.
struct Jet {
double value{};
@@ -455,8 +497,11 @@ Jet operator+(const Jet& left, const Jet& right) {
result.mixed_second[index] =
left.mixed_second[index] + right.mixed_second[index];
}
const double* left_second = left.second.ReadData();
const double* right_second = right.second.ReadData();
double* result_second = result.second.OverwriteData();
for (std::size_t index = 0U; index < kHessianSize; ++index) {
result.second[index] = left.second[index] + right.second[index];
result_second[index] = left_second[index] + right_second[index];
}
return result;
}
@@ -475,8 +520,11 @@ Jet operator-(const Jet& left, const Jet& right) {
result.mixed_second[index] =
left.mixed_second[index] - right.mixed_second[index];
}
const double* left_second = left.second.ReadData();
const double* right_second = right.second.ReadData();
double* result_second = result.second.OverwriteData();
for (std::size_t index = 0U; index < kHessianSize; ++index) {
result.second[index] = left.second[index] - right.second[index];
result_second[index] = left_second[index] - right_second[index];
}
return result;
}
@@ -506,13 +554,18 @@ Jet operator*(const Jet& left, const Jet& right) {
2.0 * left.directional_first * right.mixed_first[index] +
left.value * right.mixed_second[index];
}
const double* left_second = left.second.ReadData();
const double* right_second = right.second.ReadData();
double* result_second = result.second.OverwriteData();
Outer(left.first, right.first, result_second);
std::array<double, kHessianSize> reverse;
Outer(right.first, left.first, reverse.data());
for (std::size_t row = 0U; row < kGlobalDofCount; ++row) {
for (std::size_t column = 0U; column < kGlobalDofCount; ++column) {
const std::size_t index = row * kGlobalDofCount + column;
result.second[index] = left.second[index] * right.value +
left.first[row] * right.first[column] +
left.first[column] * right.first[row] +
left.value * right.second[index];
result_second[index] = left_second[index] * right.value +
result_second[index] + reverse[index] +
left.value * right_second[index];
}
}
return result;
@@ -529,8 +582,10 @@ Jet operator*(const double scalar, const Jet& value) {
result.mixed_first[index] = scalar * value.mixed_first[index];
result.mixed_second[index] = scalar * value.mixed_second[index];
}
const double* value_second = value.second.ReadData();
double* result_second = result.second.OverwriteData();
for (std::size_t index = 0U; index < kHessianSize; ++index) {
result.second[index] = scalar * value.second[index];
result_second[index] = scalar * value_second[index];
}
return result;
}
@@ -559,11 +614,16 @@ Jet Compose(const Jet& input, const double value, const double first,
input.first[index] * input.directional_second) +
first * input.mixed_second[index];
}
std::array<double, kGlobalDofCount> scaled_first{};
for (std::size_t row = 0U; row < kGlobalDofCount; ++row)
scaled_first[row] = second * input.first[row];
const double* input_second = input.second.ReadData();
double* result_second = result.second.OverwriteData();
Outer(scaled_first, input.first, result_second);
for (std::size_t row = 0U; row < kGlobalDofCount; ++row) {
for (std::size_t column = 0U; column < kGlobalDofCount; ++column) {
const std::size_t index = row * kGlobalDofCount + column;
result.second[index] = first * input.second[index] +
second * input.first[row] * input.first[column];
result_second[index] = first * input_second[index] + result_second[index];
}
}
return result;
@@ -613,19 +673,32 @@ Jet Atan2(const Jet& y, const Jet& x) {
const double derivative_yx =
(y.value * y.value - x.value * x.value) / radius_fourth;
const double derivative_xx = 2.0 * x.value * y.value / radius_fourth;
std::array<double, kGlobalDofCount> scaled_y{};
std::array<double, kGlobalDofCount> scaled_x{};
for (std::size_t i = 0U; i < kGlobalDofCount; ++i) {
scaled_y[i] = derivative_yy * y.first[i];
scaled_x[i] = derivative_xx * x.first[i];
}
std::array<std::array<double, kHessianSize>, 4U> products;
Outer(scaled_y, y.first, products[0U].data());
Outer(y.first, x.first, products[1U].data());
Outer(x.first, y.first, products[2U].data());
Outer(scaled_x, x.first, products[3U].data());
for (std::size_t index = 0U; index < kGlobalDofCount; ++index) {
result.first[index] =
derivative_y * y.first[index] + derivative_x * x.first[index];
}
const double* y_second = y.second.ReadData();
const double* x_second = x.second.ReadData();
double* result_second = result.second.OverwriteData();
for (std::size_t row = 0U; row < kGlobalDofCount; ++row) {
for (std::size_t column = 0U; column < kGlobalDofCount; ++column) {
const std::size_t index = row * kGlobalDofCount + column;
result.second[index] = derivative_y * y.second[index] +
derivative_x * x.second[index] +
derivative_yy * y.first[row] * y.first[column] +
derivative_yx * (y.first[row] * x.first[column] +
x.first[row] * y.first[column]) +
derivative_xx * x.first[row] * x.first[column];
result_second[index] =
derivative_y * y_second[index] + derivative_x * x_second[index] +
products[0U][index] +
derivative_yx * (products[1U][index] + products[2U][index]) +
products[3U][index];
}
}
// Use a bounded ratio for the directional third derivative only. Retain
@@ -1181,10 +1254,14 @@ Jet DrillingEnergy(const std::array<Vector3, kNodeCount>& coordinates,
DrillSpinRate(trial.rotation[node], initial_directors[node]) * gamma;
}
energy = energy + 0.5 * drilling_stiffness * gamma * gamma;
std::array<double, kGlobalDofCount> scaled_gradient{};
for (std::size_t row = 0U; row < kGlobalDofCount; ++row)
scaled_gradient[row] = drilling_stiffness * gamma.first[row];
std::array<double, kHessianSize> contribution;
Outer(scaled_gradient, gamma.first, contribution.data());
for (std::size_t row = 0U; row < kGlobalDofCount; ++row) {
for (std::size_t column = 0U; column < kGlobalDofCount; ++column) {
(*metric)(row, column) +=
drilling_stiffness * gamma.first[row] * gamma.first[column];
(*metric)(row, column) += contribution[row * kGlobalDofCount + column];
}
}
}
@@ -1505,6 +1582,7 @@ NonlinearMitc4Shell::EvaluateExternalDrillingConstraint(
const std::size_t node, const Vector3& phi, const Vector3& phi_dot,
const Vector3& force, const Vector3& force_rate,
const Vector3& force_acceleration) const {
const dense_blas_internal::ScopedLocalDenseThreads local_threads{};
if (node >= kNodeCount || !phi_dot.IsFinite() || !force.IsFinite() ||
!force_rate.IsFinite() || !force_acceleration.IsFinite()) {
return Failure<NonlinearMitc4ExternalDrillingConstraint>(
@@ -1594,6 +1672,9 @@ NonlinearMitc4Shell::EvaluateExternalDrillingConstraint(
Result<NonlinearMitc4InternalEquilibrium> EvaluateInternalResidualAndTangent(
const NonlinearMitc4Shell& element, const NonlinearMitc4TrialDofs& trial,
const Vector* coordinate_direction) {
// Element-local MKL work uses one worker only when the caller has no TLS
// override. The guard restores that request before returning to global solve.
const dense_blas_internal::ScopedLocalDenseThreads local_threads{};
if (coordinate_direction != nullptr) {
if (coordinate_direction->Size() != kGlobalDofCount) {
return Failure<NonlinearMitc4InternalEquilibrium>(