DMSwarmProjectFields#

Project a set of swarm fields onto another DM

Synopsis#

#include "petscdm.h" 
#include "petscdmda.h" 
#include "petscdmplex.h" 
#include "petscdmswarm.h" 
#include "petscksp.h" 
PetscErrorCode DMSwarmProjectFields(DM sw, DM dm, PetscInt nfields, const char *fieldnames[], Vec fields[], ScatterMode mode)

Collective

Input Parameters#

sw - the DMSWARM
dm - the DM, or NULL to use the cell DM
nfields - the number of swarm fields to project
fieldnames - the textual names of the swarm fields to project
fields - an array of Vec’s of length nfields
mode - if SCATTER_FORWARD then map particles to the continuum, and if SCATTER_REVERSE map the continuum to particles

Notes#

Currently, there are two available projection methods. The first is conservative projection, used for a DMPLEX cell DM. The second is the averaging which is used for a DMDA cell DM

\[ \phi_i = \sum_{p=0}^{np} N_i(x_p) \phi_p dJ / \sum_{p=0}^{np} N_i(x_p) dJ \]

where \(\phi_p \) is the swarm field at point \(p\), \(N_i()\) is the cell DM basis function at vertex \(i\), \(dJ\) is the determinant of the cell Jacobian and \(\phi_i\) is the projected vertex value of the field \(\phi\).

The user is responsible for destroying both the array and the individual Vec objects.

For the DMPLEX case, there is only a single vector, so the field layout in the DMPLEX must match the requested fields from the DMSwarm.

For averaging projection, nly swarm fields registered with data type of PETSC_REAL can be projected onto the cell DM, and only swarm fields of block size = 1 can currently be projected.