Structure containing Monte-Carlo function templated on EnergyBins and/or NeutrinoSpecies. More...

#include <TemplatedLocalFunctions.hpp>

Public Member Functions
void	take_time_step_on_element (gsl::not_null< std::vector< Packet > * > packets, gsl::not_null< std::mt19937 * > random_number_generator, gsl::not_null< std::array< DataVector, NeutrinoSpecies > * > single_packet_energy, double start_time, double target_end_time, const EquationsOfState::EquationOfState< true, 3 > &equation_of_state, const NeutrinoInteractionTable< EnergyBins, NeutrinoSpecies > &interaction_table, const Scalar< DataVector > &electron_fraction, const Scalar< DataVector > &rest_mass_density, const Scalar< DataVector > &temperature, const Scalar< DataVector > &lorentz_factor, const tnsr::i< DataVector, 3, Frame::Inertial > &lower_spatial_four_velocity, const Scalar< DataVector > &lapse, const tnsr::I< DataVector, 3, Frame::Inertial > &shift, const tnsr::i< DataVector, 3, Frame::Inertial > &d_lapse, const tnsr::iJ< DataVector, 3, Frame::Inertial > &d_shift, const tnsr::iJJ< DataVector, 3, Frame::Inertial > &d_inv_spatial_metric, const tnsr::ii< DataVector, 3, Frame::Inertial > &spatial_metric, const tnsr::II< DataVector, 3, Frame::Inertial > &inv_spatial_metric, const Scalar< DataVector > &sqrt_determinant_spatial_metric, const Scalar< DataVector > &cell_light_crossing_time, const Mesh< 3 > &mesh, const tnsr::I< DataVector, 3, Frame::ElementLogical > &mesh_coordinates, size_t num_ghost_zones, const std::optional< tnsr::I< DataVector, 3, Frame::Inertial > > &mesh_velocity, const InverseJacobian< DataVector, 3, Frame::ElementLogical, Frame::Inertial > &inverse_jacobian_logical_to_inertial, const Scalar< DataVector > &det_jacobian_logical_to_inertial, const Jacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &inertial_to_fluid_jacobian, const InverseJacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &inertial_to_fluid_inverse_jacobian, const DirectionalIdMap< 3, std::optional< DataVector > > &electron_fraction_ghost, const DirectionalIdMap< 3, std::optional< DataVector > > &baryon_density_ghost, const DirectionalIdMap< 3, std::optional< DataVector > > &temperature_ghost, const DirectionalIdMap< 3, std::optional< DataVector > > &cell_light_crossing_time_ghost)
	Function to take a single Monte Carlo time step on a finite difference element.

void	emit_packets (gsl::not_null< std::vector< Packet > * > packets, gsl::not_null< std::mt19937 * > random_number_generator, gsl::not_null< Scalar< DataVector > * > coupling_tilde_tau, gsl::not_null< tnsr::i< DataVector, 3, Frame::Inertial > * > coupling_tilde_s, gsl::not_null< Scalar< DataVector > * > coupling_rho_ye, const double &time_start_step, const double &time_step, const Mesh< 3 > &mesh, size_t num_ghost_zones, const std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > &emissivity_in_cell, const std::array< DataVector, NeutrinoSpecies > &single_packet_energy, const std::array< double, EnergyBins > &energy_at_bin_center, const Scalar< DataVector > &lorentz_factor, const tnsr::i< DataVector, 3, Frame::Inertial > &lower_spatial_four_velocity, const Jacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &inertial_to_fluid_jacobian, const InverseJacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &inertial_to_fluid_inverse_jacobian, const Scalar< DataVector > &cell_proper_four_volume)
	Function emitting Monte Carlo packets. More...

void	evolve_packets (gsl::not_null< std::vector< Packet > * > packets, gsl::not_null< std::mt19937 * > random_number_generator, gsl::not_null< Scalar< DataVector > * > coupling_tilde_tau, gsl::not_null< tnsr::i< DataVector, 3, Frame::Inertial > * > coupling_tilde_s, gsl::not_null< Scalar< DataVector > * > coupling_rho_ye, double final_time, const Mesh< 3 > &mesh, const tnsr::I< DataVector, 3, Frame::ElementLogical > &mesh_coordinates, size_t num_ghost_zones, const std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > &absorption_opacity_table, const std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > &scattering_opacity_table, const std::array< double, EnergyBins > &energy_at_bin_center, const Scalar< DataVector > &lorentz_factor, const tnsr::i< DataVector, 3, Frame::Inertial > &lower_spatial_four_velocity, const Scalar< DataVector > &lapse, const tnsr::I< DataVector, 3, Frame::Inertial > &shift, const tnsr::i< DataVector, 3, Frame::Inertial > &d_lapse, const tnsr::iJ< DataVector, 3, Frame::Inertial > &d_shift, const tnsr::iJJ< DataVector, 3, Frame::Inertial > &d_inv_spatial_metric, const tnsr::ii< DataVector, 3, Frame::Inertial > &spatial_metric, const tnsr::II< DataVector, 3, Frame::Inertial > &inv_spatial_metric, const Scalar< DataVector > &cell_light_crossing_time, const std::optional< tnsr::I< DataVector, 3, Frame::Inertial > > &mesh_velocity, const InverseJacobian< DataVector, 3, Frame::ElementLogical, Frame::Inertial > &inverse_jacobian_logical_to_inertial, const Jacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &inertial_to_fluid_jacobian, const InverseJacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &inertial_to_fluid_inverse_jacobian)
	Evolve Monte-Carlo packets within an element. More...

void	interpolate_opacities_at_fluid_energy (gsl::not_null< double * > absorption_opacity_packet, gsl::not_null< double * > scattering_opacity_packet, double fluid_frame_energy, size_t species, size_t index, const std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > &absorption_opacity_table, const std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > &scattering_opacity_table, const std::array< double, EnergyBins > &energy_at_bin_center)
	Interpolate the opacities from values tabulated as a function of neutrino energy in the fluid frame, to the value at the given fluid frame energy. We interpolate the logarithm of the opacity, linearly in fluid frame energy.

void	implicit_monte_carlo_interaction_rates (gsl::not_null< std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > * > emissivity_in_cell, gsl::not_null< std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > * > absorption_opacity, gsl::not_null< std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > * > scattering_opacity, gsl::not_null< std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > * > fraction_ka_to_ks, const Scalar< DataVector > &cell_light_crossing_time, const Scalar< DataVector > &electron_fraction, const Scalar< DataVector > &rest_mass_density, const Scalar< DataVector > &temperature, double minimum_temperature, const NeutrinoInteractionTable< EnergyBins, NeutrinoSpecies > &interaction_table, const EquationsOfState::EquationOfState< true, 3 > &equation_of_state)
	Function responsible to correct emissivity, absorption, and scattering rates in regions where there is a stiff coupling between the neutrinos and the fluid. This is done by transferring a fraction fraction_ka_to_ks of the absorption opacity to scattering opacity, while multiplying the emissivity by ( 1 - fraction_ka_to_ks ) to keep the equilibrium energy density constant.

Public Attributes
const double	opacity_floor = 1.e-100

Detailed Description

template<size_t EnergyBins, size_t NeutrinoSpecies>
struct Particles::MonteCarlo::TemplatedLocalFunctions< EnergyBins, NeutrinoSpecies >

Structure containing Monte-Carlo function templated on EnergyBins and/or NeutrinoSpecies.

Member Function Documentation

◆ emit_packets()

template<size_t EnergyBins, size_t NeutrinoSpecies>

void Particles::MonteCarlo::TemplatedLocalFunctions< EnergyBins, NeutrinoSpecies >::emit_packets	(	gsl::not_null< std::vector< Packet > * >	packets,
		gsl::not_null< std::mt19937 * >	random_number_generator,
		gsl::not_null< Scalar< DataVector > * >	coupling_tilde_tau,
		gsl::not_null< tnsr::i< DataVector, 3, Frame::Inertial > * >	coupling_tilde_s,
		gsl::not_null< Scalar< DataVector > * >	coupling_rho_ye,
		const double &	time_start_step,
		const double &	time_step,
		const Mesh< 3 > &	mesh,
		size_t	num_ghost_zones,
		const std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > &	emissivity_in_cell,
		const std::array< DataVector, NeutrinoSpecies > &	single_packet_energy,
		const std::array< double, EnergyBins > &	energy_at_bin_center,
		const Scalar< DataVector > &	lorentz_factor,
		const tnsr::i< DataVector, 3, Frame::Inertial > &	lower_spatial_four_velocity,
		const Jacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &	inertial_to_fluid_jacobian,
		const InverseJacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &	inertial_to_fluid_inverse_jacobian,
		const Scalar< DataVector > &	cell_proper_four_volume
	)

Function emitting Monte Carlo packets.

We emit a total energy emissivity_in_cell * cell_proper_four_volume for each grid cell, neutrino species, and neutrino energy bin. We aim for packets of energy single_packet_energy in the fluid frame. The number of packets is, in each bin b and for each species s, N = emission_in_cell[s][b] / single_packet_energy[s] and randomly rounded up or down to get integer number of packets (i.e. if we want N=2.6 packets, there is a 60 percent chance of creating a 3rd packet). The position of the packets is drawn from a homogeneous distribution in the logical frame, and the direction of propagation of the neutrinos is drawn from an isotropic distribution in the fluid frame. Specifically, the 4-momentum of a packet of energy nu in the fluid frame is

$\begin{aligned} (1) & p^{t} & = ν \\ (2) & p^{x} & = ν * s i n (θ) * c o s (ϕ) \\ (3) & p^{y} & = ν * s i n (θ) * s i n (ϕ) \\ (4) & p^{z} & = ν * c o s (t h e t a) \end{aligned}$

with $c o s (θ)$ drawn from a uniform distribution in [-1,1] and $ϕ$ from a uniform distribution in $[0, 2 * π]$ . We transform to the inertial frame $p_{t}$ and $p^{x}, p^{y}, p^{z}$ using the jacobian/inverse jacobian passed as option. The number of neutrinos in each packet is defined as n = single_packet_energy[s] / energy_at_bin_center[b] Note that the packet energy is in code units and energy of a bin in MeV.

All tensors are assumed to correspond to live points only, except for the coupling terms and emissivity, which include ghost zones.

◆ evolve_packets()

template<size_t EnergyBins, size_t NeutrinoSpecies>

void Particles::MonteCarlo::TemplatedLocalFunctions< EnergyBins, NeutrinoSpecies >::evolve_packets	(	gsl::not_null< std::vector< Packet > * >	packets,
		gsl::not_null< std::mt19937 * >	random_number_generator,
		gsl::not_null< Scalar< DataVector > * >	coupling_tilde_tau,
		gsl::not_null< tnsr::i< DataVector, 3, Frame::Inertial > * >	coupling_tilde_s,
		gsl::not_null< Scalar< DataVector > * >	coupling_rho_ye,
		double	final_time,
		const Mesh< 3 > &	mesh,
		const tnsr::I< DataVector, 3, Frame::ElementLogical > &	mesh_coordinates,
		size_t	num_ghost_zones,
		const std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > &	absorption_opacity_table,
		const std::array< std::array< DataVector, EnergyBins >, NeutrinoSpecies > &	scattering_opacity_table,
		const std::array< double, EnergyBins > &	energy_at_bin_center,
		const Scalar< DataVector > &	lorentz_factor,
		const tnsr::i< DataVector, 3, Frame::Inertial > &	lower_spatial_four_velocity,
		const Scalar< DataVector > &	lapse,
		const tnsr::I< DataVector, 3, Frame::Inertial > &	shift,
		const tnsr::i< DataVector, 3, Frame::Inertial > &	d_lapse,
		const tnsr::iJ< DataVector, 3, Frame::Inertial > &	d_shift,
		const tnsr::iJJ< DataVector, 3, Frame::Inertial > &	d_inv_spatial_metric,
		const tnsr::ii< DataVector, 3, Frame::Inertial > &	spatial_metric,
		const tnsr::II< DataVector, 3, Frame::Inertial > &	inv_spatial_metric,
		const Scalar< DataVector > &	cell_light_crossing_time,
		const std::optional< tnsr::I< DataVector, 3, Frame::Inertial > > &	mesh_velocity,
		const InverseJacobian< DataVector, 3, Frame::ElementLogical, Frame::Inertial > &	inverse_jacobian_logical_to_inertial,
		const Jacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &	inertial_to_fluid_jacobian,
		const InverseJacobian< DataVector, 4, Frame::Inertial, Frame::Fluid > &	inertial_to_fluid_inverse_jacobian
	)

Evolve Monte-Carlo packets within an element.

Evolve packets until (approximately) the provided final time following the methods of [76]. The vector of Packets should contain all MC packets that we wish to advance in time. Note that this function only handles propagation / absorption / scattering of packets, but not emission. The final time of the packet may differ from the desired final time by up to 5 percent, due to the fact that when using the diffusion approximation (for large scattering opacities) we take fixed time steps in the fluid frame, leading to unpredictable time steps in the inertial frame.

The absorption and scattering opacity tables include ghost zones, and so do the coupling terms. Other variables are only using live points.

The documentation for this struct was generated from the following file:

src/Evolution/Particles/MonteCarlo/TemplatedLocalFunctions.hpp

Public Member Functions

Public Attributes

Detailed Description

Member Function Documentation

◆ emit_packets()

◆ evolve_packets()