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

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This commit is contained in:
Emily Boudreaux
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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234
libmeanfield/impl/models/polytropic.cpp
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@@ -1,8 +1,12 @@
module;
#include <cmath>
#include <format>
#include <numbers>
#include <stdexcept>
#include <utility>
module mean_field;
import :model.structure.polytropic;
namespace mean_field::models::structure {
@@ -24,64 +28,18 @@ namespace mean_field::models::structure {
}
StructureSeed PolytropicStructure::makeInitialSeed(const StructureSeedRequest &request) const {
validateSeedRequest(request);
const seed::RadialProfile profile = seed::generateLaneEmdenProfile(
m_equationOfState, dimensions::DensityValue{request.centralDensity}, request.radialSampleCount
);
const double polytropicIndex = m_equationOfState.polytropic_index();
const std::vector<LaneEmdenPoint> laneEmdenSolution = solveLaneEmden(polytropicIndex);
const double surfaceCoordinate = laneEmdenSolution.back().coordinate;
const double centralEnthalpy =
eos::evaluate<eos::quantity::SpecificEnthalpy>(m_equationOfState, eos::DensityValue{request.centralDensity})
.value();
const double radialScaleSquared =
centralEnthalpy / (4.0 * std::numbers::pi_v<double> * mean_field::utils::G * request.centralDensity);
if (!std::isfinite(radialScaleSquared) || radialScaleSquared <= 0.0) {
throw std::runtime_error(
"The polytropic Lane-Emden radial scale is not "
"finite and positive."
);
}
const double radialScale = std::sqrt(radialScaleSquared);
StructureSeed seed;
seed.radius.SetSize(request.radialSampleCount);
seed.density.SetSize(request.radialSampleCount);
seed.enthalpy.SetSize(request.radialSampleCount);
seed.stellarRadius = radialScale * surfaceCoordinate;
seed.centralDensity = request.centralDensity;
seed.centralEnthalpy = centralEnthalpy;
std::size_t interpolationIndex = 0;
for (int sampleIndex = 0; sampleIndex < request.radialSampleCount; ++sampleIndex) {
const double sampleFraction =
static_cast<double>(sampleIndex) / static_cast<double>(request.radialSampleCount - 1);
const double dimensionlessRadius = sampleFraction * surfaceCoordinate;
const double laneEmdenValue =
interpolateLaneEmdenValue(laneEmdenSolution, dimensionlessRadius, interpolationIndex);
const double density = request.centralDensity * std::pow(laneEmdenValue, polytropicIndex);
seed.radius(sampleIndex) = radialScale * dimensionlessRadius;
seed.density(sampleIndex) = density;
seed.enthalpy(sampleIndex) =
eos::evaluate<eos::quantity::SpecificEnthalpy>(m_equationOfState, eos::DensityValue{density}).value();
}
seed.radius(0) = 0.0;
seed.density(0) = request.centralDensity;
seed.enthalpy(0) = centralEnthalpy;
const int surfaceIndex = request.radialSampleCount - 1;
seed.radius(surfaceIndex) = seed.stellarRadius;
seed.density(surfaceIndex) = 0.0;
seed.enthalpy(surfaceIndex) = 0.0;
return seed;
return {
.radius = profile.radius,
.density = profile.density,
.enthalpy = profile.specificEnthalpy,
.stellarRadius = profile.stellarRadius.value(),
.centralDensity = profile.centralDensity.value(),
.centralEnthalpy = profile.centralSpecificEnthalpy.value()
};
}
void PolytropicStructure::validate() const {
@@ -90,8 +48,7 @@ namespace mean_field::models::structure {
if (!std::isfinite(polytropicIndex) || polytropicIndex < 1.0 || polytropicIndex >= 5.0) {
throw std::invalid_argument(
std::format(
"PolytropicStructure requires a finite-radius "
"polytrope with 1 <= n < 5. Instead n = {} was "
"PolytropicStructure requires a finite-radius polytrope with 1 <= n < 5. Instead n = {} was "
"provided.",
polytropicIndex
)
@@ -101,163 +58,10 @@ namespace mean_field::models::structure {
if (!std::isfinite(m_targetMass) || m_targetMass <= 0.0) {
throw std::invalid_argument(
std::format(
"The target stellar mass must be finite and "
"positive. Instead a value of {} was provided.",
"The target stellar mass must be finite and positive. Instead a value of {} was provided.",
m_targetMass
)
);
}
}
void PolytropicStructure::validateSeedRequest(const StructureSeedRequest &request) {
if (!std::isfinite(request.centralDensity) || request.centralDensity <= 0.0) {
throw std::invalid_argument(
std::format(
"The seed central density must be finite and "
"positive. Instead a value of {} was provided.",
request.centralDensity
)
);
}
if (request.radialSampleCount < 2) {
throw std::invalid_argument(
std::format(
"A polytropic seed requires at least two radial "
"samples. Instead {} samples were requested.",
request.radialSampleCount
)
);
}
}
PolytropicStructure::LaneEmdenDerivative PolytropicStructure::evaluateLaneEmdenRhs(
const double coordinate,
const double value,
const double derivative,
const double polytropicIndex
) {
const double nonnegativeValue = std::max(value, 0.0);
return {
.value = derivative,
.derivative = -2.0 * derivative / coordinate - std::pow(nonnegativeValue, polytropicIndex)
};
}
PolytropicStructure::LaneEmdenPoint PolytropicStructure::takeLaneEmdenStep(
const LaneEmdenPoint &point,
const double step,
const double polytropicIndex
) {
const LaneEmdenDerivative first =
evaluateLaneEmdenRhs(point.coordinate, point.value, point.derivative, polytropicIndex);
const LaneEmdenDerivative second = evaluateLaneEmdenRhs(
point.coordinate + 0.5 * step, point.value + 0.5 * step * first.value,
point.derivative + 0.5 * step * first.derivative, polytropicIndex
);
const LaneEmdenDerivative third = evaluateLaneEmdenRhs(
point.coordinate + 0.5 * step, point.value + 0.5 * step * second.value,
point.derivative + 0.5 * step * second.derivative, polytropicIndex
);
const LaneEmdenDerivative fourth = evaluateLaneEmdenRhs(
point.coordinate + step, point.value + step * third.value, point.derivative + step * third.derivative,
polytropicIndex
);
return {
.coordinate = point.coordinate + step,
.value = point.value + step / 6.0 * (first.value + 2.0 * second.value + 2.0 * third.value + fourth.value),
.derivative =
point.derivative +
step / 6.0 * (first.derivative + 2.0 * second.derivative + 2.0 * third.derivative + fourth.derivative)
};
}
std::vector<PolytropicStructure::LaneEmdenPoint> PolytropicStructure::solveLaneEmden(const double polytropicIndex) {
constexpr double initialCoordinate = 1.0e-6;
constexpr double integrationStep = 1.0e-3;
constexpr int maximumStepCount = 2'000'000;
const double coordinateSquared = initialCoordinate * initialCoordinate;
const double coordinateCubed = coordinateSquared * initialCoordinate;
const double coordinateFourth = coordinateSquared * coordinateSquared;
LaneEmdenPoint point{
.coordinate = initialCoordinate,
.value = 1.0 - coordinateSquared / 6.0 + polytropicIndex * coordinateFourth / 120.0,
.derivative = -initialCoordinate / 3.0 + polytropicIndex * coordinateCubed / 30.0
};
std::vector<LaneEmdenPoint> solution;
solution.reserve(8192);
solution.push_back({.coordinate = 0.0, .value = 1.0, .derivative = 0.0});
solution.push_back(point);
for (int stepIndex = 0; stepIndex < maximumStepCount; ++stepIndex) {
LaneEmdenPoint nextPoint = takeLaneEmdenStep(point, integrationStep, polytropicIndex);
if (!std::isfinite(nextPoint.value)) {
throw std::runtime_error(
"The Lane-Emden integration produced a non-finite "
"solution before reaching the stellar surface."
);
}
if (nextPoint.value <= 0.0) {
const double rootFraction = point.value / (point.value - nextPoint.value);
solution.push_back(
{.coordinate = point.coordinate + rootFraction * (nextPoint.coordinate - point.coordinate),
.value = 0.0,
.derivative = point.derivative + rootFraction * (nextPoint.derivative - point.derivative)}
);
return solution;
}
solution.push_back(nextPoint);
point = nextPoint;
}
throw std::runtime_error(
"The Lane-Emden integration did not reach its first zero "
"within the configured step limit."
);
}
double PolytropicStructure::interpolateLaneEmdenValue(
const std::vector<LaneEmdenPoint> &solution,
const double coordinate,
std::size_t &lowerIndex
) {
while (lowerIndex + 1 < solution.size() && solution[lowerIndex + 1].coordinate < coordinate) {
++lowerIndex;
}
if (lowerIndex + 1 >= solution.size()) {
return 0.0;
}
const LaneEmdenPoint &lower = solution[lowerIndex];
const LaneEmdenPoint &upper = solution[lowerIndex + 1];
const double interval = upper.coordinate - lower.coordinate;
if (interval <= 0.0) {
throw std::runtime_error(
"The Lane-Emden interpolation grid is not strictly "
"increasing."
);
}
const double fraction = (coordinate - lower.coordinate) / interval;
return std::clamp(lower.value + fraction * (upper.value - lower.value), 0.0, 1.0);
}
}; // namespace mean_field::models::structure
} // namespace mean_field::models::structure