VlasovAdvection.c File Reference

Contains the function to compute the hyperbolic flux for the Vlasov equations over the domain. More...

#include <math.h>
#include <basic.h>
#include <arrayfunctions.h>
#include <physicalmodels/vlasov.h>
#include <mpivars.h>
#include <hypar.h>

Go to the source code of this file.

Functions
double	VlasovAdvectionCoeff (int *, int, void *)
int	VlasovAdvection (double *f, double *u, int dir, void *s, double t)

Detailed Description

Contains the function to compute the hyperbolic flux for the Vlasov equations over the domain.

Author

John Loffeld

Definition in file VlasovAdvection.c.

Function Documentation

double VlasovAdvectionCoeff	(	int *	idx,
		int	dir,
		void *	s
	)

Returns the advection coefficient at a given grid index \(c\), where

\begin{equation} c = v_i, \end{equation}

if dir < Vlasov::ndims_x ( \(i = {\rm dir}\)), and

\begin{equation} c = E_i, \end{equation}

the electric field if dir >= Vlasov::ndims_x ( \(i = \) dir-Vlasov::ndims_x).

Note: this function assumes that the electric field has already been set.

Parameters

idx	grid index
dir	Spatial dimension
s	Solver object of type HyPar

Definition at line 28 of file VlasovAdvectionCoeff.c.

{

  HyPar  *solver = (HyPar*)  s;
  Vlasov *param  = (Vlasov*) solver->physics;

  int* dim    = solver->dim_local;
  int  ghosts = solver->ghosts;

  double retval = DBL_MAX;

  if (dir < param->ndims_x) {

    int veldim = dir + param->ndims_x;
    _GetCoordinate_(veldim,idx[veldim],dim,ghosts,solver->x,retval);

  }  else {

    int ndims_x = param->ndims_x;
    int dim_x[ndims_x]; _ArrayCopy1D_(dim, dim_x, ndims_x);

    int idx_x[ndims_x];
    _ArrayCopy1D_(idx, idx_x, ndims_x);
    int p; _ArrayIndex1D_(ndims_x, dim_x, idx_x, ghosts, p);
    retval = param->e_field[ndims_x*p+(dir-ndims_x)];
    
  }

  return retval;

}

int VlasovAdvection	(	double *	f,
		double *	u,
		int	dir,
		void *	s,
		double	t
	)

Compute the hyperbolic flux over the local domain.

\begin{equation} {\bf F}\left({\bf u}(x,v)\right) = c {\bf u}(x,v), \end{equation}

where the advection coefficient \(c\) is computed by VlasovAdvectionCoeff().

Parameters

f	Array to hold the computed flux (same size and layout as u)
u	Array containing the conserved solution
dir	Spatial dimension
s	Solver object of type HyPar
t	Current time

Definition at line 22 of file VlasovAdvection.c.

{

  HyPar  *solver = (HyPar*)  s;
  Vlasov *param  = (Vlasov*) solver->physics;

  int* dim    = solver->dim_local;
  int  ghosts = solver->ghosts;
  int  ndims  = solver->ndims;

  // set bounds for array index to include ghost points
  int bounds[ndims];
  _ArrayCopy1D_(dim,bounds,ndims);
  for (int i=0; i<ndims; i++) bounds[i] += 2*ghosts;

  // set offset such that index is compatible with ghost point arrangement
  int offset[ndims];
  _ArraySetValue_(offset,ndims,-ghosts);

  int done = 0; 
  int index_wog[ndims];
  int index[ndims]; _ArraySetValue_(index,ndims,0);
  while (!done) {

    _ArrayCopy1D_(index, index_wog, ndims);
    for (int i = 0; i < ndims; i++) index_wog[i] -= ghosts;
    double adv_coeff = VlasovAdvectionCoeff(index_wog, dir, solver);

    int p; _ArrayIndex1DWO_(ndims,dim,index,offset,ghosts,p);
    f[p] = adv_coeff * u[p];
    _ArrayIncrementIndex_(ndims,bounds,index,done);

  }

  return 0;
}