Class for evolving non-interacting matter particles. More...

#include <particles.h>

Collaboration diagram for cosmo::Particles:

Public Member Functions
void	init (idx_t n_particles)
	Create random particles. More...

void	addParticle (Particle< real_t > particle)
	Add an individual particle. More...

particle_vec *	getParticleVec ()

real_t	getFractionalIndex (real_t x)
	Compute non-integer index at a point.

idx_t	getIndexBelow (real_t x)
	Returns the index "below" a point (floor of getFractionalIndex) More...

idx_t	getNearestIndex (real_t x)
	Returns the index nearest a point (rounds getFractionalIndex)

void	setX_d (real_t X[3], real_t x_d[3])
	Sets a fractional distance between grid points. More...

ParticleMetricPrimitives< real_t >	interpolatePrimitivesFromCorners (ParticleMetricPrimitives< real_t > corner_pp_in[2][2][2], real_t x_d[3])
	Linearly interpolate metric quantities from corners of a "box". More...

ParticleMetricPrimitives< real_t >	interpolatePrimitivesFromCornersIncomplete (ParticleMetricPrimitives< real_t > corner_pp_in[2][2][2], real_t x_d[3])
	Only set some metric components. More...

real_t	linearInterpolation (real_t C000, real_t C001, real_t C010, real_t C011, real_t C100, real_t C101, real_t C110, real_t C111, real_t x_d[3])

ParticleMetricPrimitives< real_t >	getInterpolatedPrimitivesIncomplete (Particle< real_t > *p, map_t &bssn_fields)
	Interpolate some metric primitives required for geodesic integration. More...

ParticleMetricPrimitives< real_t >	getInterpolatedPrimitives (Particle< real_t > *p, map_t &bssn_fields)
	Interpolate metric primitives required for geodesic integration. More...

void	RKStep (ParticleRegister< real_t > *pr, real_t h, real_t RK_sum_coeff, map_t &bssn_fields)
	Implementation for evaluating a single RK step. More...

void	RK1Step (map_t &bssn_fields)

void	RK2Step (map_t &bssn_fields)

void	RK3Step (map_t &bssn_fields)

void	RK4Step (map_t &bssn_fields)

void	stepInit (map_t &bssn_fields)

void	regSwap_c_a ()

void	stepTerm ()

real_t	getKernelWeight (real_t r, real_t r_s)

void	addParticlesToBSSNSrc (BSSN *bssnSim)

void	addParticleToBSSNSrc (Particle< real_t > *p_c, map_t &bssn_fields)

Private Attributes
particle_vec *	particles

Detailed Description

Class for evolving non-interacting matter particles.

Class stores a (private) vector of particles, and contains routines for particle evolution, interpolation, and interactions with GR (BSSN) fields.

Member Function Documentation

void cosmo::Particles::addParticle ( Particle< real_t > particle )

Add an individual particle.

Add an individual particle to the internal list of particles

Parameters

particle Particle struct

void cosmo::Particles::addParticlesToBSSNSrc ( BSSN * bssnSim )

Set bssn _a source registers using data from particle _c register

idx_t cosmo::Particles::getIndexBelow ( real_t x )

Returns the index "below" a point (floor of getFractionalIndex)

Returns: index associated with position

ParticleMetricPrimitives< real_t > cosmo::Particles::getInterpolatedPrimitives	(	Particle< real_t > *	p,
		map_t &	bssn_fields
	)

Interpolate metric primitives required for geodesic integration.

Interpolate metric primitives (eg, variables in a ParticleMetricPrimitives struct) required for geodesic integration near a particular particle.

Parameters

p	Instance of particle to compute interpolated metric quantities near (Particle type).
bssn_fields	Map from bssn class to fields.

Returns: Returns ParticleMetricPrimitives with values near the particle

ParticleMetricPrimitives< real_t > cosmo::Particles::getInterpolatedPrimitivesIncomplete	(	Particle< real_t > *	p,
		map_t &	bssn_fields
	)

Interpolate some metric primitives required for geodesic integration.

Interpolate some metric primitives (eg, only some variables in a ParticleMetricPrimitives struct: alpha, phi, gamma_ij) required for geodesic integration near a particular particle. See also: getInterpolatedPrimitives

Parameters

p	Instance of particle to compute interpolated metric quantities near (Particle type).
bssn_fields	Map from bssn class to fields.

Returns: Returns ParticleMetricPrimitives with values near the particle

void cosmo::Particles::init ( idx_t n_particles )

Create random particles.

Add particles with randomized positions, zero velocity, and unit mass to internal particles vector.

Parameters

n_particles number of particles to create

ParticleMetricPrimitives< real_t > cosmo::Particles::interpolatePrimitivesFromCorners	(	ParticleMetricPrimitives< real_t >	corner_pp_in[2][2][2],
		real_t	x_d[3]
	)

Linearly interpolate metric quantities from corners of a "box".

Linearly interpolate metric quantities from corners of a "box"

Parameters

corner_pp_in	A 2x2x2 array containing metric values at corners of the "box"
x_d	fractional position between corners inside the "box" to interpolate values at (see setX_d)

Returns: [description]

ParticleMetricPrimitives< real_t > cosmo::Particles::interpolatePrimitivesFromCornersIncomplete	(	ParticleMetricPrimitives< real_t >	corner_pp_in[2][2][2],
		real_t	x_d[3]
	)

Only set some metric components.

Only set some metric components: gamma_ij, rootdetg, and alpha see also: getInterpolatedPrimitivesIncomplete

Parameters

corner_pp_in 2x2x2 array of metric primitives at corners (incomplete)

Returns: metric primitives (incomplete)

void cosmo::Particles::RKStep	(	ParticleRegister< real_t > *	pr,
		real_t	h,
		real_t	RK_sum_coeff,
		map_t &	bssn_fields
	)

Implementation for evaluating a single RK step.

General implementation for computing one of the RK steps: y_p; y_a = y_c = yp; y_f = 0 (TODO) y_a = y_p

y_c = y_p + dt/2 * f(y_a) // RK1 step y_f += y_c y_a <-> y_c

y_c = y_p + dt/2 * f(y_a) // RK2 step y_f += 2 y_c y_a <-> y_c

y_c = y_p + dt * f(y_a) // RK3 step y_f += y_c y_a <-> y_c

y_c = y_p + dt/2 * f(y_a) // RK4 step y_f += y_c y_a <-> y_c

(y_f = 5y_p + 1/2 K1 + K2 + K3 + 1/2 K4) y_f = y_f / 3 - 2/3 y_p // finalize y_f <-> y_p

Using Baumgarte & Shapiro, 5.223-5.225

For a single RK step, we can just do: y_c = y_p + h * f(y_a) and y_f += RK_sum_coeff * y_c

Parameters

	pr	Register of particles to integrate
[in]	h	step size for particular RK step
[in]	RK_sum_coeff	coefficient when adding RK step
	bssn_fields	Map from bssn class to fields.

void cosmo::Particles::setX_d	(	real_t	X[3],
		real_t	x_d[3]
	)

Sets a fractional distance between grid points.

Stores the fractional distance between grid points of a given point. Eg, for dx = 0.5, the value 1.23 is 46/100 the way between gridpoints at 1.0 and 1.5, so 0.46 is computed. Following this, supplying the point (1.23, 4.56, 7.89) as an argument for X would cause x_d to be set to (0.46, 0.12, 0.78)

Parameters

X	true position
x_d	fractional position (passed by reference; values are mutated)

The documentation for this class was generated from the following files:

components/particles/particles.h
components/particles/particles.cc

Public Member Functions

Private Attributes

Detailed Description

Member Function Documentation