kernel_hydro.h File Reference

Kernel functions for SPH (scalar and vector version). More...

#include <config.h>
#include <math.h>
#include "dimension.h"
#include "error.h"
#include "inline.h"
#include "minmax.h"
#include "vector.h"

Include dependency graph for kernel_hydro.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	kernel_gamma_inv   ((float)(1. / kernel_gamma))
#define	kernel_gamma2   ((float)(kernel_gamma * kernel_gamma))
#define	kernel_ivals_f   ((float)(kernel_ivals))
#define	kernel_root
#define	kernel_norm   ((float)(hydro_dimension_unit_sphere * kernel_gamma_dim))

Functions
	__attribute__ ((always_inline)) INLINE static void kernel_deval(float u
	Computes the kernel function and its derivative.
	for (int k=2;k<=kernel_degree;k++) = x * w + coeffs[k]
	for (int k=2;k< kernel_degree;k++) dw_dx
void	hydro_kernel_dump (int N)
	Test the SPH kernel function by dumping it in the interval [0,1].

Variables
float *restrict	W = w * kernel_constant * kernel_gamma_inv_dim
float *restrict float *restrict	dW_dx
const int	temp = (int)(x * kernel_ivals_f)
const int	ind = temp > kernel_ivals ? kernel_ivals : temp
const float *const	coeffs = &kernel_coeffs[ind * (kernel_degree + 1)]
float	w = coeffs[0] * x + coeffs[1]
float	dw_dx = coeffs[0]

Detailed Description

Kernel functions for SPH (scalar and vector version).

All constants and kernel coefficients are taken from table 1 of Dehnen & Aly, MNRAS, 425, pp. 1062-1082 (2012).

Definition in file kernel_hydro.h.

Macro Definition Documentation

kernel_gamma2

#define kernel_gamma2   ((float)(kernel_gamma * kernel_gamma))

Definition at line 206 of file kernel_hydro.h.

kernel_gamma_inv

#define kernel_gamma_inv   ((float)(1. / kernel_gamma))

Definition at line 205 of file kernel_hydro.h.

kernel_ivals_f

#define kernel_ivals_f   ((float)(kernel_ivals))

Definition at line 233 of file kernel_hydro.h.

kernel_norm

#define kernel_norm   ((float)(hydro_dimension_unit_sphere * kernel_gamma_dim))

Definition at line 241 of file kernel_hydro.h.

kernel_root

#define kernel_root

Value:

  ((float)(kernel_coeffs[kernel_degree]) * kernel_constant * \
   kernel_gamma_inv_dim)

Definition at line 236 of file kernel_hydro.h.

Function Documentation

__attribute__()

__attribute__

(

(always_inline)

)

Computes the kernel function and its derivative.

Computes the kernel function derivative.

Computes the kernel function in double precision.

Computes the kernel function.

The kernel function needs to be mutliplied by \(h^{-d}\) and the gradient by \(h^{-(d+1)}\), where \(d\) is the dimensionality of the problem.

Returns 0 if \(u > \gamma = H/h\).

Parameters

u	The ratio of the distance to the smoothing length \(u = x/h\).
W	(return) The value of the kernel function \(W(x,h)\).
dW_dx	(return) The norm of the gradient of \(|\nabla W(x,h)|\).

The kernel function needs to be mutliplied by \(h^{-d}\), where \(d\) is the dimensionality of the problem.

Returns 0 if \(u > \gamma = H/h\)

Parameters

u	The ratio of the distance to the smoothing length \(u = x/h\).
W	(return) The value of the kernel function \(W(x,h)\).

Required for computing the projected kernel because rounding error causes problems for the GSL integration function if we evaluate in single precision.

The kernel function needs to be mutliplied by \(h^{-d}\), where \(d\) is the dimensionality of the problem.

Returns 0 if \(u > \gamma = H/h\)

Parameters

u	The ratio of the distance to the smoothing length \(u = x/h\).
W	(return) The value of the kernel function \(W(x,h)\).

The kernel function needs to be mutliplied by \(h^{-d}\) and the gradient by \(h^{-(d+1)}\), where \(d\) is the dimensionality of the problem.

Returns 0 if \(u > \gamma = H/h\).

Parameters

u	The ratio of the distance to the smoothing length \(u = x/h\).
dW_dx	(return) The norm of the gradient of \(|\nabla W(x,h)|\).

for() [1/2]

for

(

)

for() [2/2]

for

(

int

k = 2;k<=kernel_degree;k++

)

= x * w + coeffs[k]

Definition at line 273 of file kernel_hydro.h.

References coeffs, dw_dx, and w.

hydro_kernel_dump()

void hydro_kernel_dump

(

int

N

)

Test the SPH kernel function by dumping it in the interval [0,1].

Parameters

N	number of intervals in [0,1].

Definition at line 31 of file kernel_hydro.c.

References dw_dx, kernel_deval(), and w.

Here is the call graph for this function:

Variable Documentation

coeffs

const float *const coeffs = &kernel_coeffs[ind * (kernel_degree + 1)]

Definition at line 266 of file kernel_hydro.h.

Referenced by for(), swift2::kernels::legacy::kernelHydro::kernel_deval(), and swift2::kernels::legacy::kernelHydro::kernel_eval().

dW_dx

* dW_dx

Initial value:

{
 
  
  const float x = u * kernel_gamma_inv

Definition at line 258 of file kernel_hydro.h.

Referenced by swift2::kernels::legacy::kernelHydro::kernel_deval().

dw_dx

float dw_dx = coeffs[0]

Definition at line 270 of file kernel_hydro.h.

Referenced by for(), hydro_kernel_dump(), and swift2::kernels::legacy::kernelHydro::kernel_deval().

ind

const int ind = temp > kernel_ivals ? kernel_ivals : temp

Definition at line 265 of file kernel_hydro.h.

Referenced by swift2::kernels::legacy::kernelHydro::kernel_deval(), and swift2::kernels::legacy::kernelHydro::kernel_eval().

temp

const int temp = (int)(x * kernel_ivals_f)

Definition at line 264 of file kernel_hydro.h.

Referenced by exahype2::fv::musclhancock::internal::computeTimeDerivative_LoopBody(), swift2::kernels::legacy::hydro_update_smoothing_length_and_rerun_if_required(), swift2::kernels::legacy::kernelHydro::kernel_deval(), swift2::kernels::legacy::kernelHydro::kernel_eval(), tarch::la::lu(), applications::exahype2::ccz4::ncp(), examples::exahype2::mgccz4::ncp(), tl::basic_iterator< C >::operator++(), swift2::kernels::legacy::hydroDimensions::pow_dimension_plus_one(), applications::exahype2::ccz4::source(), examples::exahype2::mgccz4::source(), and applications::exahype2::ccz4::TestingOutput().

W

* W = w * kernel_constant * kernel_gamma_inv_dim

Definition at line 258 of file kernel_hydro.h.

Referenced by swift2::kernels::legacy::kernelHydro::kernel_deval(), and swift2::kernels::legacy::kernelHydro::kernel_eval().

w

double w = coeffs[0] * x + coeffs[1]

Definition at line 269 of file kernel_hydro.h.

Referenced by applications::exahype2::CompressibleNavierStokes::NavierStokesSolver::boundaryConditions(), applications::exahype2::CompressibleNavierStokes::NavierStokesSolver::calculateDerivatives(), applications::exahype2::CompressibleNavierStokes::NavierStokesSolver::flux(), for(), hydro_kernel_dump(), applications::exahype2::CompressibleNavierStokes::NavierStokesSolver::initialCondition(), swift2::kernels::legacy::kernelHydro::kernel_deval(), swift2::kernels::legacy::kernelHydro::kernel_eval(), main(), applications::exahype2::CompressibleNavierStokes::NavierStokesSolver::maxEigenvalue(), applications::exahype2::CompressibleNavierStokes::NavierStokesSolver::nonconservativeProduct(), Numerics::rotate_dofs(), Numerics::rotate_dofs_inverse(), TP::Utilities::scalarproduct(), and applications::exahype2::CompressibleNavierStokes::NavierStokesSolver::sourceTerm().