perf(jacobian-action): major updates to jacobian action application by removing redudant quadrature work. ~5x increase in speed

This commit is contained in:
2026-09-02 17:01:50 -04:00
parent 85500fef3b
commit 25510008dd
74 changed files with 8967 additions and 814 deletions

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module;
#include <algorithm>
#include <chrono>
#include <cmath>
#include <complex>
#include <cstdint>
#include <limits>
#include <memory>
#include <ranges>
#include <stdexcept>
#include <string>
#include <utility>
#include <vector>
#include <Eigen/Dense>
#include <Eigen/Eigenvalues>
#include <Eigen/SVD>
#include <mfem.hpp>
#include <mpi.h>
module mean_field;
import :solver.preconditioning_diagnostics;
namespace {
using Clock = std::chrono::steady_clock;
[[nodiscard]] double seconds_between(
const Clock::time_point start,
const Clock::time_point finish
) {
return std::chrono::duration<double>(finish - start).count();
}
void verify_finite_vector(
const mfem::Vector &vector,
const char *message
) {
for (int index = 0; index < vector.Size(); ++index) {
if (!std::isfinite(vector(index))) {
throw std::invalid_argument(message);
}
}
}
[[nodiscard]] double global_dot(
const mfem::Vector &left,
const mfem::Vector &right,
const MPI_Comm communicator
) {
if (communicator == MPI_COMM_NULL) {
throw std::invalid_argument("Preconditioning diagnostics require a valid MPI communicator.");
}
if (left.Size() != right.Size()) {
throw std::invalid_argument("A distributed inner product received vectors with different sizes.");
}
const double localValue = left * right;
double globalValue = 0.0;
MPI_Allreduce(&localValue, &globalValue, 1, MPI_DOUBLE, MPI_SUM, communicator);
return globalValue;
}
[[nodiscard]] double global_norm(
const mfem::Vector &vector,
const MPI_Comm communicator
) {
return std::sqrt(std::max(global_dot(vector, vector, communicator), 0.0));
}
[[nodiscard]] mean_field::solver::OperatorApplicationStatistics maximum_rank_statistics(
const mean_field::solver::OperatorApplicationStatistics &local,
const MPI_Comm communicator
) {
unsigned long long localApplications = static_cast<unsigned long long>(local.applications);
unsigned long long maximumApplications{0};
MPI_Allreduce(&localApplications, &maximumApplications, 1, MPI_UNSIGNED_LONG_LONG, MPI_MAX, communicator);
mean_field::solver::OperatorApplicationStatistics result;
result.applications = static_cast<std::uint64_t>(maximumApplications);
MPI_Allreduce(&local.totalSeconds, &result.totalSeconds, 1, MPI_DOUBLE, MPI_MAX, communicator);
MPI_Allreduce(&local.maximumSeconds, &result.maximumSeconds, 1, MPI_DOUBLE, MPI_MAX, communicator);
return result;
}
[[nodiscard]] double maximum_rank_value(
const double localValue,
const MPI_Comm communicator
) {
double result = 0.0;
MPI_Allreduce(&localValue, &result, 1, MPI_DOUBLE, MPI_MAX, communicator);
return result;
}
[[nodiscard]] mean_field::solver::PreconditionerLifecycleStatistics maximum_rank_lifecycle_statistics(
const mean_field::solver::PreconditionerLifecycleStatistics &local,
const MPI_Comm communicator
) {
unsigned long long localSetups = static_cast<unsigned long long>(local.setups);
unsigned long long localRefreshes = static_cast<unsigned long long>(local.refreshes);
unsigned long long maximumSetups{0};
unsigned long long maximumRefreshes{0};
MPI_Allreduce(&localSetups, &maximumSetups, 1, MPI_UNSIGNED_LONG_LONG, MPI_MAX, communicator);
MPI_Allreduce(&localRefreshes, &maximumRefreshes, 1, MPI_UNSIGNED_LONG_LONG, MPI_MAX, communicator);
mean_field::solver::PreconditionerLifecycleStatistics result;
result.setups = static_cast<std::uint64_t>(maximumSetups);
result.refreshes = static_cast<std::uint64_t>(maximumRefreshes);
MPI_Allreduce(&local.setupSeconds, &result.setupSeconds, 1, MPI_DOUBLE, MPI_MAX, communicator);
MPI_Allreduce(&local.refreshSeconds, &result.refreshSeconds, 1, MPI_DOUBLE, MPI_MAX, communicator);
return result;
}
[[nodiscard]] Eigen::MatrixXd copy_hessenberg(
const Eigen::MatrixXd &source,
const int rowCount,
const int columnCount
) {
return source.topLeftCorner(rowCount, columnCount);
}
} // namespace
namespace mean_field::solver {
InstrumentedOperator::InstrumentedOperator(const mfem::Operator &operation)
: mfem::Operator(
operation.Height(),
operation.Width()
),
m_operation(std::addressof(operation)) {
}
void InstrumentedOperator::Mult(
const mfem::Vector &input,
mfem::Vector &output
) const {
const Clock::time_point start = Clock::now();
m_operation->Mult(input, output);
const double elapsed = seconds_between(start, Clock::now());
++m_statistics.applications;
m_statistics.totalSeconds += elapsed;
m_statistics.maximumSeconds = std::max(m_statistics.maximumSeconds, elapsed);
}
void InstrumentedOperator::ResetStatistics() const noexcept {
m_statistics = {};
}
const OperatorApplicationStatistics &InstrumentedOperator::GetStatistics() const noexcept {
return m_statistics;
}
const mfem::Operator &InstrumentedOperator::GetOperation() const noexcept {
return *m_operation;
}
InstrumentedPreconditioner::InstrumentedPreconditioner(mfem::Solver &preconditioner)
: mfem::Solver(
preconditioner.Height(),
preconditioner.Width(),
preconditioner.iterative_mode
),
m_preconditioner(std::addressof(preconditioner)) {
}
void InstrumentedPreconditioner::SetOperator(const mfem::Operator &operation) {
const Clock::time_point start = Clock::now();
m_preconditioner->SetOperator(operation);
m_lifecycleStatistics.setupSeconds += seconds_between(start, Clock::now());
++m_lifecycleStatistics.setups;
if (m_preconditioner->Height() != Height() || m_preconditioner->Width() != Width()) {
throw std::invalid_argument("An instrumented preconditioner changed dimensions during SetOperator.");
}
}
void InstrumentedPreconditioner::Mult(
const mfem::Vector &input,
mfem::Vector &output
) const {
const Clock::time_point start = Clock::now();
m_preconditioner->Mult(input, output);
const double elapsed = seconds_between(start, Clock::now());
++m_statistics.applications;
m_statistics.totalSeconds += elapsed;
m_statistics.maximumSeconds = std::max(m_statistics.maximumSeconds, elapsed);
}
void InstrumentedPreconditioner::ResetStatistics() const noexcept {
m_statistics = {};
}
const OperatorApplicationStatistics &InstrumentedPreconditioner::GetStatistics() const noexcept {
return m_statistics;
}
const PreconditionerLifecycleStatistics &InstrumentedPreconditioner::GetLifecycleStatistics() const noexcept {
return m_lifecycleStatistics;
}
const mfem::Solver &InstrumentedPreconditioner::GetPreconditioner() const noexcept {
return *m_preconditioner;
}
IdentityPreconditioner::IdentityPreconditioner(const int size) : mfem::Solver(size) {
if (size <= 0) {
throw std::invalid_argument("An identity preconditioner requires a positive dimension.");
}
}
void IdentityPreconditioner::SetOperator(const mfem::Operator &operation) {
if (operation.Height() != Height() || operation.Width() != Width()) {
throw std::invalid_argument("The identity preconditioner received an incompatible operator.");
}
}
void IdentityPreconditioner::Mult(
const mfem::Vector &input,
mfem::Vector &output
) const {
if (input.Size() != Width()) {
throw std::invalid_argument("The identity preconditioner received an input with the wrong size.");
}
output = input;
}
FixedRightPreconditionedOperator::FixedRightPreconditionedOperator(
const mfem::Operator &jacobian,
const mfem::Solver &inversePreconditioner
)
: mfem::Operator(
jacobian.Height(),
inversePreconditioner.Width()
),
m_jacobian(std::addressof(jacobian)),
m_inversePreconditioner(std::addressof(inversePreconditioner)),
m_preconditionedDirection(inversePreconditioner.Height()) {
if (jacobian.Height() != jacobian.Width()) {
throw std::invalid_argument("A preconditioned stellar Jacobian must be square.");
}
if (inversePreconditioner.Height() != jacobian.Width() || inversePreconditioner.Width() != jacobian.Height()) {
throw std::invalid_argument("The inverse preconditioner does not map residuals into Jacobian states.");
}
if (Height() != Width()) {
throw std::invalid_argument("The fixed right-preconditioned product must be square.");
}
}
void FixedRightPreconditionedOperator::Mult(
const mfem::Vector &input,
mfem::Vector &output
) const {
if (input.Size() != Width()) {
throw std::invalid_argument("The right-preconditioned operator received an input with the wrong size.");
}
m_inversePreconditioner->Mult(input, m_preconditionedDirection);
m_jacobian->Mult(m_preconditionedDirection, output);
}
const mfem::Operator &FixedRightPreconditionedOperator::GetJacobian() const noexcept {
return *m_jacobian;
}
const mfem::Solver &FixedRightPreconditionedOperator::GetInversePreconditioner() const noexcept {
return *m_inversePreconditioner;
}
void ResidualHistoryMonitor::Reset() {
mfem::IterativeSolverMonitor::Reset();
m_history.clear();
}
void ResidualHistoryMonitor::MonitorResidual(
const int iteration,
const double norm,
const mfem::Vector &,
const bool final
) {
m_history.push_back({.iteration = iteration, .reportedNorm = norm, .final = final});
}
const std::vector<IterationResidualMeasurement> &ResidualHistoryMonitor::GetHistory() const noexcept {
return m_history;
}
DirectResidualMeasurement measureDirectResidual(
const mfem::Operator &jacobian,
const mfem::Vector &rightHandSide,
const mfem::Vector &solution,
const std::span<const operators::RootBlockDescriptor> residualBlocks,
const MPI_Comm communicator,
const double denominatorFloor
) {
if (jacobian.Height() != jacobian.Width() || rightHandSide.Size() != jacobian.Height() ||
solution.Size() != jacobian.Width()) {
throw std::invalid_argument("Direct residual measurement received incompatible linear-system dimensions.");
}
if (!std::isfinite(denominatorFloor) || denominatorFloor <= 0.0) {
throw std::invalid_argument("The direct-residual denominator floor must be finite and positive.");
}
verify_finite_vector(rightHandSide, "Direct residual measurement received a non-finite right-hand side.");
verify_finite_vector(solution, "Direct residual measurement received a non-finite solution.");
int expectedOffset = 0;
for (const operators::RootBlockDescriptor &block : residualBlocks) {
if (block.kind != operators::RootBlockKind::residual || block.offset != expectedOffset || block.size < 0 ||
block.offset + block.size > jacobian.Height() || !std::isfinite(block.scale) || block.scale <= 0.0) {
throw std::invalid_argument("Residual block descriptors do not form the canonical equation layout.");
}
expectedOffset += block.size;
}
if (expectedOffset != jacobian.Height()) {
throw std::invalid_argument("Residual block descriptors do not cover the complete equation vector.");
}
mfem::Vector action(jacobian.Height());
jacobian.Mult(solution, action);
if (action.Size() != rightHandSide.Size()) {
throw std::runtime_error("The Jacobian returned an action with the wrong size.");
}
mfem::Vector trueResidual(rightHandSide);
trueResidual -= action;
verify_finite_vector(trueResidual, "Direct residual measurement produced a non-finite residual.");
DirectResidualMeasurement measurement;
measurement.rightHandSideNorm = global_norm(rightHandSide, communicator);
measurement.trueResidualNorm = global_norm(trueResidual, communicator);
const double denominator = std::max(measurement.rightHandSideNorm, denominatorFloor);
measurement.relativeResidual = measurement.trueResidualNorm / denominator;
measurement.blocks.reserve(residualBlocks.size());
for (const operators::RootBlockDescriptor &block : residualBlocks) {
const mfem::Vector blockRightHandSide(
const_cast<mfem::real_t *>(rightHandSide.GetData()) + block.offset, block.size
);
const mfem::Vector blockResidual(trueResidual.GetData() + block.offset, block.size);
const double blockRightHandSideNorm = global_norm(blockRightHandSide, communicator);
const double blockResidualNorm = global_norm(blockResidual, communicator);
const double blockDenominator = std::max(blockRightHandSideNorm, denominatorFloor);
const double globalResidualFraction =
measurement.trueResidualNorm > denominatorFloor
? blockResidualNorm * blockResidualNorm /
(measurement.trueResidualNorm * measurement.trueResidualNorm)
: 0.0;
measurement.blocks.push_back(
{.stableId = std::string(block.stableId),
.size = block.size,
.descriptorScale = block.scale,
.rightHandSideNorm = blockRightHandSideNorm,
.trueResidualNorm = blockResidualNorm,
.blockRelativeResidual = blockResidualNorm / blockDenominator,
.scaledRightHandSideNorm = blockRightHandSideNorm / block.scale,
.scaledTrueResidualNorm = blockResidualNorm / block.scale,
.contributionToGlobalRelativeResidual = blockResidualNorm / denominator,
.fractionOfGlobalSquaredResidualNorm = globalResidualFraction}
);
}
return measurement;
}
LinearSolveMeasurement measureLinearSolve(
const mfem::IterativeSolver &iterativeSolver,
const mfem::Operator &jacobian,
const mfem::Vector &rightHandSide,
const mfem::Vector &solution,
const std::span<const operators::RootBlockDescriptor> residualBlocks,
const OperatorApplicationStatistics &jacobianStatistics,
const OperatorApplicationStatistics &inversePreconditionerStatistics,
const PreconditionerLifecycleStatistics &inversePreconditionerLifecycle,
const ResidualHistoryMonitor &monitor,
const double localSolveSeconds,
const MPI_Comm communicator,
const double denominatorFloor
) {
if (!std::isfinite(localSolveSeconds) || localSolveSeconds < 0.0) {
throw std::invalid_argument("A linear-solve duration must be finite and nonnegative.");
}
const DirectResidualMeasurement directResidual =
measureDirectResidual(jacobian, rightHandSide, solution, residualBlocks, communicator, denominatorFloor);
const double reportedInitial = iterativeSolver.GetInitialNorm();
const double reportedFinal = iterativeSolver.GetFinalNorm();
const double reportedReduction =
std::abs(reportedInitial) > denominatorFloor ? std::abs(reportedFinal) / std::abs(reportedInitial) : 0.0;
double digitsPerJacobianApplication = 0.0;
if (jacobianStatistics.applications > 0 && directResidual.relativeResidual >= 0.0 &&
std::isfinite(directResidual.relativeResidual)) {
digitsPerJacobianApplication = -std::log10(std::max(directResidual.relativeResidual, denominatorFloor)) /
static_cast<double>(jacobianStatistics.applications);
}
return {
.solverConverged = iterativeSolver.GetConverged(),
.outerIterations = iterativeSolver.GetNumIterations(),
.solverReportedInitialNorm = reportedInitial,
.solverReportedFinalNorm = reportedFinal,
.solverReportedResidualReduction = reportedReduction,
.trueResidualDigitsReducedPerJacobianApplication = digitsPerJacobianApplication,
.solveSecondsMaximumRank = maximum_rank_value(localSolveSeconds, communicator),
.jacobian = maximum_rank_statistics(jacobianStatistics, communicator),
.inversePreconditioner = maximum_rank_statistics(inversePreconditionerStatistics, communicator),
.inversePreconditionerLifecycle =
maximum_rank_lifecycle_statistics(inversePreconditionerLifecycle, communicator),
.directResidual = directResidual,
.reportedResidualHistory = monitor.GetHistory()
};
}
ArnoldiSpectralMeasurement measureArnoldiSpectrum(
const mfem::Operator &operation,
const mfem::Vector &initialDirection,
const MPI_Comm communicator,
const ArnoldiOptions &options
) {
if (operation.Height() != operation.Width() || operation.Width() <= 0) {
throw std::invalid_argument("Arnoldi diagnostics require a nonempty square operator.");
}
if (initialDirection.Size() != operation.Width()) {
throw std::invalid_argument("The Arnoldi initial direction has the wrong size.");
}
if (options.krylovDimension <= 0 || !std::isfinite(options.breakdownRelativeTolerance) ||
options.breakdownRelativeTolerance < 0.0 || !std::isfinite(options.ritzConvergenceRelativeTolerance) ||
options.ritzConvergenceRelativeTolerance < 0.0) {
throw std::invalid_argument("Arnoldi diagnostic options are invalid.");
}
verify_finite_vector(initialDirection, "Arnoldi diagnostics received a non-finite initial direction.");
const Clock::time_point measurementStart = Clock::now();
OperatorApplicationStatistics localApplicationStatistics;
const double initialNorm = global_norm(initialDirection, communicator);
if (!std::isfinite(initialNorm) || initialNorm <= 0.0) {
throw std::invalid_argument("Arnoldi diagnostics require a nonzero initial direction.");
}
const int requestedDimension = std::min(options.krylovDimension, operation.Width());
Eigen::MatrixXd hessenberg = Eigen::MatrixXd::Zero(requestedDimension + 1, requestedDimension);
std::vector<mfem::Vector> basis;
basis.reserve(static_cast<std::size_t>(requestedDimension + 1));
basis.emplace_back(initialDirection);
basis.back() /= initialNorm;
int achievedDimension{0};
bool invariantSubspaceFound{false};
for (int column = 0; column < requestedDimension; ++column) {
mfem::Vector candidate(operation.Height());
const Clock::time_point applicationStart = Clock::now();
operation.Mult(basis[static_cast<std::size_t>(column)], candidate);
const double applicationSeconds = seconds_between(applicationStart, Clock::now());
++localApplicationStatistics.applications;
localApplicationStatistics.totalSeconds += applicationSeconds;
localApplicationStatistics.maximumSeconds =
std::max(localApplicationStatistics.maximumSeconds, applicationSeconds);
if (candidate.Size() != operation.Height()) {
throw std::runtime_error("The Arnoldi operator returned a vector with the wrong size.");
}
verify_finite_vector(candidate, "The Arnoldi operator produced a non-finite vector.");
const double unorthogonalizedNorm = global_norm(candidate, communicator);
const int passCount = options.reorthogonalize ? 2 : 1;
for (int pass = 0; pass < passCount; ++pass) {
for (int row = 0; row <= column; ++row) {
const double projection = global_dot(basis[static_cast<std::size_t>(row)], candidate, communicator);
hessenberg(row, column) += projection;
candidate.Add(-projection, basis[static_cast<std::size_t>(row)]);
}
}
const double nextNorm = global_norm(candidate, communicator);
hessenberg(column + 1, column) = nextNorm;
achievedDimension = column + 1;
const double breakdownScale = std::max(unorthogonalizedNorm, 1.0);
if (nextNorm <= options.breakdownRelativeTolerance * breakdownScale) {
invariantSubspaceFound = true;
break;
}
if (column + 1 < requestedDimension) {
candidate /= nextNorm;
basis.push_back(std::move(candidate));
}
}
if (achievedDimension <= 0) {
throw std::runtime_error("Arnoldi diagnostics did not construct a Krylov projection.");
}
const Eigen::MatrixXd projected = copy_hessenberg(hessenberg, achievedDimension, achievedDimension);
const Eigen::MatrixXd projectedRectangular =
copy_hessenberg(hessenberg, achievedDimension + 1, achievedDimension);
Eigen::EigenSolver<Eigen::MatrixXd> eigenSolver(projected, true);
if (eigenSolver.info() != Eigen::Success) {
throw std::runtime_error("The projected Arnoldi eigenproblem did not converge.");
}
Eigen::JacobiSVD<Eigen::MatrixXd> singularValueDecomposition(projectedRectangular);
if (singularValueDecomposition.info() != Eigen::Success) {
throw std::runtime_error("The projected Arnoldi singular-value problem did not converge.");
}
ArnoldiSpectralMeasurement measurement;
measurement.requestedDimension = requestedDimension;
measurement.achievedDimension = achievedDimension;
measurement.invariantSubspaceFound = invariantSubspaceFound;
const OperatorApplicationStatistics globalApplicationStatistics =
maximum_rank_statistics(localApplicationStatistics, communicator);
measurement.operatorApplications = globalApplicationStatistics.applications;
measurement.operatorApplicationSecondsMaximumRank = globalApplicationStatistics.totalSeconds;
measurement.operatorMaximumApplicationSecondsMaximumRank = globalApplicationStatistics.maximumSeconds;
measurement.ritzValues.reserve(static_cast<std::size_t>(achievedDimension));
const Eigen::VectorXd singularValues = singularValueDecomposition.singularValues();
measurement.projectedLargestSingularValue = singularValues(0);
measurement.projectedSmallestSingularValue = singularValues(singularValues.size() - 1);
measurement.projectedConditionProxy =
measurement.projectedSmallestSingularValue > 0.0
? measurement.projectedLargestSingularValue / measurement.projectedSmallestSingularValue
: std::numeric_limits<double>::infinity();
const double finalSubdiagonal = hessenberg(achievedDimension, achievedDimension - 1);
std::complex<double> centroid{0.0, 0.0};
const auto eigenvalues = eigenSolver.eigenvalues();
const auto eigenvectors = eigenSolver.eigenvectors();
for (int index = 0; index < achievedDimension; ++index) {
const std::complex<double> eigenvalue = eigenvalues(index);
const double eigenvectorNorm = eigenvectors.col(index).norm();
const double residualEstimate =
eigenvectorNorm > 0.0
? std::abs(finalSubdiagonal * eigenvectors(achievedDimension - 1, index)) / eigenvectorNorm
: std::numeric_limits<double>::infinity();
const double convergenceScale = std::max(std::abs(eigenvalue), 1.0);
const double relativeResidualEstimate = residualEstimate / convergenceScale;
const bool converged = relativeResidualEstimate <= options.ritzConvergenceRelativeTolerance;
measurement.ritzValues.push_back(
{.realPart = eigenvalue.real(),
.imaginaryPart = eigenvalue.imag(),
.magnitude = std::abs(eigenvalue),
.distanceFromOne = std::abs(eigenvalue - std::complex<double>{1.0, 0.0}),
.residualEstimate = residualEstimate,
.relativeResidualEstimate = relativeResidualEstimate,
.converged = converged}
);
centroid += eigenvalue;
measurement.convergedRitzValueCount += converged ? 1 : 0;
measurement.negativeRealPartCount += eigenvalue.real() < 0.0 ? 1 : 0;
}
centroid /= static_cast<double>(achievedDimension);
measurement.centroidRealPart = centroid.real();
measurement.centroidImaginaryPart = centroid.imag();
measurement.minimumMagnitude = std::numeric_limits<double>::infinity();
measurement.minimumRealPart = std::numeric_limits<double>::infinity();
measurement.maximumRealPart = -std::numeric_limits<double>::infinity();
double squaredDistanceFromOne{0.0};
double squaredClusterRadius{0.0};
for (const RitzValueMeasurement &ritz : measurement.ritzValues) {
const std::complex<double> value{ritz.realPart, ritz.imaginaryPart};
measurement.minimumMagnitude = std::min(measurement.minimumMagnitude, ritz.magnitude);
measurement.maximumMagnitude = std::max(measurement.maximumMagnitude, ritz.magnitude);
measurement.minimumRealPart = std::min(measurement.minimumRealPart, ritz.realPart);
measurement.maximumRealPart = std::max(measurement.maximumRealPart, ritz.realPart);
measurement.maximumAbsoluteImaginaryPart =
std::max(measurement.maximumAbsoluteImaginaryPart, std::abs(ritz.imaginaryPart));
squaredDistanceFromOne += ritz.distanceFromOne * ritz.distanceFromOne;
squaredClusterRadius += std::norm(value - centroid);
double pairDefect = std::numeric_limits<double>::infinity();
for (const RitzValueMeasurement &candidate : measurement.ritzValues) {
pairDefect = std::min(
pairDefect,
std::abs(std::complex<double>{candidate.realPart, candidate.imaginaryPart} - std::conj(value))
);
}
measurement.conjugatePairDefect = std::max(measurement.conjugatePairDefect, pairDefect);
}
measurement.rmsDistanceFromOne = std::sqrt(squaredDistanceFromOne / achievedDimension);
measurement.rmsClusterRadius = std::sqrt(squaredClusterRadius / achievedDimension);
const double projectedFrobeniusSquared = projected.squaredNorm();
if (projectedFrobeniusSquared > 0.0) {
const Eigen::MatrixXd normalityCommutator =
projected.transpose() * projected - projected * projected.transpose();
measurement.projectedDepartureFromNormality = normalityCommutator.norm() / projectedFrobeniusSquared;
}
const Eigen::MatrixXd hermitianPart = 0.5 * (projected + projected.transpose());
Eigen::SelfAdjointEigenSolver<Eigen::MatrixXd> fieldOfValuesSolver(hermitianPart);
if (fieldOfValuesSolver.info() != Eigen::Success) {
throw std::runtime_error("The projected field-of-values problem did not converge.");
}
measurement.projectedFieldOfValuesMinimumRealPart = fieldOfValuesSolver.eigenvalues().minCoeff();
measurement.projectedFieldOfValuesMaximumRealPart = fieldOfValuesSolver.eigenvalues().maxCoeff();
const double localMeasurementSeconds = seconds_between(measurementStart, Clock::now());
const double localNonApplicationSeconds =
std::max(localMeasurementSeconds - localApplicationStatistics.totalSeconds, 0.0);
measurement.measurementSecondsMaximumRank = maximum_rank_value(localMeasurementSeconds, communicator);
measurement.nonApplicationSecondsMaximumRank = maximum_rank_value(localNonApplicationSeconds, communicator);
return measurement;
}
std::vector<RitzValueMeasurement> selectRitzValues(
const ArnoldiSpectralMeasurement &measurement,
const RitzValueOrdering ordering,
const int count
) {
if (count < 0) {
throw std::invalid_argument("The requested Ritz-value count must be nonnegative.");
}
std::vector<RitzValueMeasurement> selected;
selected.reserve(measurement.ritzValues.size());
for (const RitzValueMeasurement &value : measurement.ritzValues) {
if (value.converged) {
selected.push_back(value);
}
}
std::ranges::sort(selected, [ordering](const RitzValueMeasurement &left, const RitzValueMeasurement &right) {
switch (ordering) {
case RitzValueOrdering::closest_to_zero:
return left.magnitude < right.magnitude;
case RitzValueOrdering::farthest_from_one:
return left.distanceFromOne > right.distanceFromOne;
case RitzValueOrdering::smallest_real_part:
return left.realPart < right.realPart;
case RitzValueOrdering::largest_magnitude:
return left.magnitude > right.magnitude;
}
return false;
});
if (static_cast<int>(selected.size()) > count) {
selected.resize(static_cast<std::size_t>(count));
}
return selected;
}
} // namespace mean_field::solver