gridfire Namespace Reference

Namespaces
namespace	approx8
namespace	diagnostics
namespace	exceptions
namespace	expectations
namespace	io
namespace	partition
namespace	rates
namespace	reaclib
namespace	reaction
namespace	screening
namespace	solver
namespace	trigger
namespace	utils

Classes
class	AdaptiveEngineView
	An engine view that dynamically adapts the reaction network based on runtime conditions. More...
class	DefinedEngineView
class	DynamicEngine
	Abstract class for engines supporting Jacobian and stoichiometry operations. More...
struct	EnergyDerivatives
class	Engine
	Abstract base class for a reaction network engine. More...
class	EngineView
	Abstract base class for a "view" of a reaction network engine. More...
class	FileDefinedEngineView
class	GraphEngine
	A reaction network engine that uses a graph-based representation. More...
class	MultiscalePartitioningEngineView
	An engine view that partitions the reaction network into multiple groups based on timescales. More...
struct	NetIn
struct	NetOut
class	Network
class	NetworkPrimingEngineView
	Provides a view of a DynamicEngine filtered to reactions involving a specified priming species. More...
struct	PrimingReport
	Captures the result of a network priming operation. More...
struct	QSECacheConfig
	Configuration struct for the QSE cache. More...
struct	QSECacheKey
	Key struct for the QSE abundance cache. More...
class	Reaction
	Represents a single nuclear reaction from a specific data source. More...
class	ReactionSet
struct	StepDerivatives
	Structure holding derivatives and energy generation for a network step. More...

Concepts
concept	IsArithmeticOrAD
	Concept for types allowed in engine calculations.
concept	EngineType
	Concept for types allowed as engine bases in EngineView.

Typedefs
using	SparsityPattern = std::vector<std::pair<size_t, size_t>>
typedef CppAD::AD< double >	ADDouble
	Alias for CppAD AD type for double precision.
using	BuildDepthType = std::variant<NetworkBuildDepth, int>
	Variant specifying either a predefined NetworkBuildDepth or a custom integer depth.

Enumerations
enum class	NetworkBuildDepth {   Full = -1 , Shallow = 1 , SecondOrder = 2 , ThirdOrder = 3 ,   FourthOrder = 4 , FifthOrder = 5 }
	Specifies supported depths for building the reaction network. More...
enum class	PrimingReportStatus {   FULL_SUCCESS = 0 , NO_SPECIES_TO_PRIME = 1 , MAX_ITERATIONS_REACHED = 2 , FAILED_TO_FINALIZE_COMPOSITION = 3 ,   FAILED_TO_FIND_CREATION_CHANNEL = 4 , FAILED_TO_FIND_PRIMING_REACTIONS = 5 , BASE_NETWORK_TOO_SHALLOW = 6 }
	Enumerates outcome codes for a network priming operation. More...
enum	NetworkFormat { APPROX8 , REACLIB , UNKNOWN }

Functions
reaction::ReactionSet	build_reaclib_nuclear_network (const fourdst::composition::Composition &composition, const rates::weak::WeakRateInterpolator &weakInterpolator, BuildDepthType maxLayers=NetworkBuildDepth::Full, bool reverse=false)
	Builds a nuclear reaction network from the Reaclib library based on an initial composition.
PrimingReport	primeNetwork (const NetIn &netIn, DynamicEngine &engine)
	Primes absent species in the network to their equilibrium abundances.
double	calculateDestructionRateConstant (const DynamicEngine &engine, const fourdst::atomic::Species &species, const fourdst::composition::Composition &composition, double T9, double rho)
	Computes the destruction rate constant for a specific species.
double	calculateCreationRate (const DynamicEngine &engine, const fourdst::atomic::Species &species, const fourdst::composition::Composition &composition, double T9, double rho)
	Computes the creation rate for a specific species.
ReactionSet	build_nuclear_network (const Composition &composition, const rates::weak::WeakRateInterpolator &weak_interpolator, BuildDepthType maxLayers, bool reverse_reaclib)
const reaction::Reaction *	findDominantCreationChannel (const DynamicEngine &engine, const Species &species, const fourdst::composition::Composition &comp, const double T9, const double rho)
double	calculateDestructionRateConstant (const DynamicEngine &engine, const Species &species, const Composition &comp, const double T9, const double rho)
double	calculateCreationRate (const DynamicEngine &engine, const Species &species, const Composition &comp, const double T9, const double rho)
std::string	trim_whitespace (const std::string &str)

Variables
static constexpr double	MIN_DENSITY_THRESHOLD = 1e-18
	Minimum density threshold below which reactions are ignored.
static constexpr double	MIN_ABUNDANCE_THRESHOLD = 1e-18
	Minimum abundance threshold below which species are ignored.
static constexpr double	MIN_JACOBIAN_THRESHOLD = 1e-24
	Minimum value for Jacobian matrix entries.
std::map< PrimingReportStatus, std::string >	PrimingReportStatusStrings
	Mapping from PrimingReportStatus codes to human-readable strings.
static std::unordered_map< NetworkFormat, std::string >	FormatStringLookup

Typedef Documentation

ADDouble

typedef CppAD::AD<double> gridfire::ADDouble

Alias for CppAD AD type for double precision.

This alias simplifies the use of the CppAD automatic differentiation type.

BuildDepthType

using gridfire::BuildDepthType = std::variant<NetworkBuildDepth, int>

Variant specifying either a predefined NetworkBuildDepth or a custom integer depth.

Precondition

If using the integer alternative, the value must be >= 0 or -1 to indicate a full build.

Postcondition

The network builder will interpret and apply the specified depth to control reaction expansion.

SparsityPattern

using gridfire::SparsityPattern = std::vector<std::pair<size_t, size_t>>

Enumeration Type Documentation

NetworkBuildDepth

enum class gridfire::NetworkBuildDepth

strong

Specifies supported depths for building the reaction network.

Values:

• Full: Build the complete network (infinite depth).
• Shallow: Build only direct reactions (depth = 1).
• SecondOrder: Include reactions up to second order (depth = 2).
• ThirdOrder: Include reactions up to third order (depth = 3).
• FourthOrder: Include reactions up to fourth order (depth = 4).
• FifthOrder: Include reactions up to fifth order (depth = 5).

Note

For custom build depths, see BuildDepthType.

Enumerator
Full
Shallow
SecondOrder
ThirdOrder
FourthOrder
FifthOrder

NetworkFormat

enum gridfire::NetworkFormat

Enumerator
APPROX8	Approx8 nuclear reaction network format.
REACLIB	General REACLIB nuclear reaction network format.
UNKNOWN

PrimingReportStatus

enum class gridfire::PrimingReportStatus

strong

Enumerates outcome codes for a network priming operation.

These status codes indicate the reason for success or failure of the priming process:

• FULL_SUCCESS: Priming completed successfully with all species processed.
• NO_SPECIES_TO_PRIME: There were no species eligible for priming.
• MAX_ITERATIONS_REACHED: The algorithm reached its iteration limit without converging.
• FAILED_TO_FINALIZE_COMPOSITION: Unable to build a valid Composition object at end.
• FAILED_TO_FIND_CREATION_CHANNEL: No reaction path found to create the priming species.
• FAILED_TO_FIND_PRIMING_REACTIONS: No reactions containing the priming species were found.
• BASE_NETWORK_TOO_SHALLOW: The provided base network depth was insufficient for priming.

See also

PrimingReport for data associated with each status.

Enumerator
FULL_SUCCESS
NO_SPECIES_TO_PRIME
MAX_ITERATIONS_REACHED
FAILED_TO_FINALIZE_COMPOSITION
FAILED_TO_FIND_CREATION_CHANNEL
FAILED_TO_FIND_PRIMING_REACTIONS
BASE_NETWORK_TOO_SHALLOW

Function Documentation

build_nuclear_network()

ReactionSet gridfire::build_nuclear_network	(	const Composition &	composition,
		const rates::weak::WeakRateInterpolator &	weak_interpolator,
		BuildDepthType	maxLayers,
		bool	reverse_reaclib )

build_reaclib_nuclear_network()

reaction::ReactionSet gridfire::build_reaclib_nuclear_network	(	const fourdst::composition::Composition &	composition,
		const rates::weak::WeakRateInterpolator &	weakInterpolator,
		BuildDepthType	maxLayers = NetworkBuildDepth::Full,
		bool	reverse = false )

Builds a nuclear reaction network from the Reaclib library based on an initial composition.

Constructs a layered reaction network by collecting reactions up to the specified depth from the Reaclib dataset. Starting species are those with non-zero mass fractions in the input composition. Layers expand by including products of collected reactions until the depth limit. Optionally selects reverse reactions instead of forward.

See implementation in construction.cpp for details on the layering algorithm, logging, and performance.

Parameters

composition	Mapping of isotopic species to their mass fractions; species with positive mass fraction seed the network.
weakInterpolator
maxLayers	Variant specifying either a predefined NetworkBuildDepth or a custom integer depth; negative depth (Full) collects all reactions, zero is invalid.
reverse	If true, collects reverse reactions (decays or back-reactions); if false, uses forward reactions.

Precondition

composition must have at least one species with positive mass fraction.

Resolved integer depth from maxLayers must not be zero.

Postcondition

Returned network includes only reactions satisfying the depth and reverse criteria.

Returns

A LogicalReactionSet encapsulating the collected reactions for graph-based engines.

Exceptions

std::logic_error

If the resolved network depth is zero (no reactions can be collected).

calculateCreationRate() [1/2]

double gridfire::calculateCreationRate	(	const DynamicEngine &	engine,
		const fourdst::atomic::Species &	species,
		const fourdst::composition::Composition &	composition,
		double	T9,
		double	rho )

Computes the creation rate for a specific species.

Sums molar reaction flows for all reactions where the species appears as a product (positive stoichiometry).

Parameters

engine	Engine providing the current set of network reactions and flow calculations.
species	The atomic species whose creation rate is computed.
composition	Composition object containing current abundances.
T9	Temperature in units of 10^9 K.
rho	Density of the medium.

Precondition

Y.size() matches engine.getNetworkReactions().size() mapping species order.

Postcondition

Returned creation rate is non-negative.

Returns

Sum of stoichiometry-weighted creation flows for the species.

calculateCreationRate() [2/2]

double gridfire::calculateCreationRate	(	const DynamicEngine &	engine,
		const Species &	species,
		const Composition &	comp,
		const double	T9,
		const double	rho )

calculateDestructionRateConstant() [1/2]

double gridfire::calculateDestructionRateConstant	(	const DynamicEngine &	engine,
		const fourdst::atomic::Species &	species,
		const fourdst::composition::Composition &	composition,
		double	T9,
		double	rho )

Computes the destruction rate constant for a specific species.

Calculates the sum of molar reaction flows for all reactions where the species is a reactant (negative stoichiometry) after scaling its abundance to unity.

Parameters

engine	Engine providing the current set of network reactions and flow calculations.
species	The atomic species whose destruction rate is computed.
composition	Current composition providing abundances for all species.
T9	Temperature in units of 10^9 K.
rho	Density of the medium.

Precondition

Y.size() matches engine.getNetworkReactions().size() mapping species order.

Postcondition

Returned rate constant is non-negative.

Returns

Sum of absolute stoichiometry-weighted destruction flows for the species.

calculateDestructionRateConstant() [2/2]

double gridfire::calculateDestructionRateConstant	(	const DynamicEngine &	engine,
		const Species &	species,
		const Composition &	comp,
		const double	T9,
		const double	rho )

findDominantCreationChannel()

const reaction::Reaction * gridfire::findDominantCreationChannel	(	const DynamicEngine &	engine,
		const Species &	species,
		const fourdst::composition::Composition &	comp,
		const double	T9,
		const double	rho )

primeNetwork()

PrimingReport gridfire::primeNetwork	(	const NetIn &	netIn,
		DynamicEngine &	engine )

Primes absent species in the network to their equilibrium abundances.

Primes absent species in the network to their equilibrium abundances using a robust, two-stage approach.

Executes a network priming algorithm that iteratively rebuilds the reaction network, calculates equilibrium mass fractions for species with zero initial abundance, and applies mass transfers based on reaction flows.

Refer to priming.cpp for implementation details on logging, algorithmic steps, and error handling.

Parameters

netIn	Input network data containing initial composition, temperature, and density.
engine	DynamicEngine used to build and evaluate the reaction network.

Precondition

netIn.composition defines species and their mass fractions; engine is constructed with a valid network.

Postcondition

engine.networkReactions restored to its initial state; returned report contains primedComposition, massFractionChanges for each species, success flag, and status code.

Returns

PrimingReport encapsulating the results of the priming operation.

This function implements a robust network priming algorithm that avoids the pitfalls of sequential, one-by-one priming. The previous, brittle method could allow an early priming reaction to consume all of a shared reactant, starving later reactions. This new, two-stage method ensures that all priming reactions are considered collectively, competing for the same limited pool of initial reactants in a physically consistent manner.

The algorithm proceeds in three main stages:

1. Calculation Stage: It first loops through all species that need priming. For each one, it calculates its theoretical equilibrium mass fraction and identifies the dominant creation channel. Crucially, it does not modify any abundances at this stage. Instead, it stores these calculations as a list of "mass transfer requests".
2. Collective Scaling Stage: It then processes the full list of requests to determine the total "debit" required from each reactant. By comparing these total debits to the initially available mass of each reactant, it calculates a single, global scalingFactor. If any reactant is overdrawn, this factor will be less than 1.0, ensuring that no reactant's abundance can go negative.
3. Application Stage: Finally, it loops through the requests again, applying the mass transfers. Each calculated equilibrium mass fraction and corresponding reactant debit is multiplied by the global scalingFactor before being applied to the final composition. This ensures that if resources are limited, all primed species are scaled down proportionally.

Parameters

netIn	Input network data containing initial composition, temperature, and density.
engine	DynamicEngine used to build and evaluate the reaction network.

Returns

PrimingReport encapsulating the results of the priming operation, including the new robustly primed composition.

trim_whitespace()

std::string gridfire::trim_whitespace

(

const std::string &

str

)

Variable Documentation

FormatStringLookup

std::unordered_map<NetworkFormat, std::string> gridfire::FormatStringLookup

inlinestatic

Initial value:

= {
        {APPROX8, "Approx8"},
        {REACLIB, "REACLIB"},
        {UNKNOWN, "Unknown"}
    }

MIN_ABUNDANCE_THRESHOLD

double gridfire::MIN_ABUNDANCE_THRESHOLD = 1e-18

staticconstexpr

Minimum abundance threshold below which species are ignored.

Species with abundances below this threshold are treated as zero in reaction rate calculations. This helps to improve performance by avoiding unnecessary calculations for trace species.

MIN_DENSITY_THRESHOLD

double gridfire::MIN_DENSITY_THRESHOLD = 1e-18

staticconstexpr

Minimum density threshold below which reactions are ignored.

Reactions are not calculated if the density falls below this threshold. This helps to improve performance by avoiding unnecessary calculations in very low-density regimes.

MIN_JACOBIAN_THRESHOLD

double gridfire::MIN_JACOBIAN_THRESHOLD = 1e-24

staticconstexpr

Minimum value for Jacobian matrix entries.

Jacobian matrix entries with absolute values below this threshold are treated as zero to maintain sparsity and improve performance.

PrimingReportStatusStrings

std::map<PrimingReportStatus, std::string> gridfire::PrimingReportStatusStrings

inline

Initial value:

= {
        {PrimingReportStatus::FULL_SUCCESS, "Full Success"},
        {PrimingReportStatus::NO_SPECIES_TO_PRIME, "No Species to Prime"},
        {PrimingReportStatus::MAX_ITERATIONS_REACHED, "Max Iterations Reached"},
        {PrimingReportStatus::FAILED_TO_FINALIZE_COMPOSITION, "Failed to Finalize Composition"},
        {PrimingReportStatus::FAILED_TO_FIND_CREATION_CHANNEL, "Failed to Find Creation Channel"},
        {PrimingReportStatus::FAILED_TO_FIND_PRIMING_REACTIONS, "Failed to Find Priming Reactions"},
        {PrimingReportStatus::BASE_NETWORK_TOO_SHALLOW, "Base Network Too Shallow"}
    }

Mapping from PrimingReportStatus codes to human-readable strings.

Used when formatting or logging the priming status. No preconditions. The map contains entries for all PrimingReportStatus values.