DMAddBoundary#

Add a boundary condition to a model represented by a DM

Synopsis#

#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMAddBoundary(DM dm, DMBoundaryConditionType type, const char name[], DMLabel label, PetscInt Nv, const PetscInt values[], PetscInt field, PetscInt Nc, const PetscInt comps[], void (*bcFunc)(void), void (*bcFunc_t)(void), void *ctx, PetscInt *bd)

Collective

Input Parameters#

dm - The DM, with a PetscDS that matches the problem being constrained
type - The type of condition, e.g. DM_BC_ESSENTIAL_ANALYTIC, DM_BC_ESSENTIAL_FIELD (Dirichlet), or DM_BC_NATURAL (Neumann)
name - The BC name
label - The label defining constrained points
Nv - The number of DMLabel values for constrained points
values - An array of values for constrained points
field - The field to constrain
Nc - The number of constrained field components (0 will constrain all fields)
comps - An array of constrained component numbers
bcFunc - A pointwise function giving boundary values
bcFunc_t - A pointwise function giving the time deriative of the boundary values, or NULL
ctx - An optional user context for bcFunc

Output Parameter#

bd - (Optional) Boundary number

Options Database Keys#

-bc_ - Overrides the boundary ids
-bc__comp - Overrides the boundary components

Notes#

Both bcFunc abd bcFunc_t will depend on the boundary condition type. If the type if DM_BC_ESSENTIAL, then the calling sequence is:

void bcFunc(PetscInt dim, PetscReal time, const PetscReal x[], PetscInt Nc, PetscScalar bcval[])

If the type is DM_BC_ESSENTIAL_FIELD or other _FIELD value, then the calling sequence is:

  void bcFunc(PetscInt dim, PetscInt Nf, PetscInt NfAux,
              const PetscInt uOff[], const PetscInt uOff_x[], const PetscScalar u[], const PetscScalar u_t[], const PetscScalar u_x[],
              const PetscInt aOff[], const PetscInt aOff_x[], const PetscScalar a[], const PetscScalar a_t[], const PetscScalar a_x[],
              PetscReal time, const PetscReal x[], PetscScalar bcval[])

dim - the spatial dimension
Nf - the number of fields
uOff - the offset into u[] and u_t[] for each field
uOff_x - the offset into u_x[] for each field
u - each field evaluated at the current point
u_t - the time derivative of each field evaluated at the current point
u_x - the gradient of each field evaluated at the current point
aOff - the offset into a[] and a_t[] for each auxiliary field
aOff_x - the offset into a_x[] for each auxiliary field
a - each auxiliary field evaluated at the current point
a_t - the time derivative of each auxiliary field evaluated at the current point
a_x - the gradient of auxiliary each field evaluated at the current point
t - current time
x - coordinates of the current point
numConstants - number of constant parameters
constants - constant parameters
bcval - output values at the current point