PetscDSSetRHSResidual#

Set the pointwise residual function for explicit timestepping for a given test field

Synopsis#

#include "petscds.h" 
PetscErrorCode PetscDSSetRHSResidual(PetscDS ds, PetscInt f, void (*f0)(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 t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f0[]), void (*f1)(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 t, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar f1[]))

Not Collective

Input Parameters#

ds - The PetscDS
f - The test field number
f0 - integrand for the test function term
f1 - integrand for the test function gradient term

Clling sequence for the callbacks f0 and f1#

  f0(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 t, const PetscReal x[], PetscScalar f0[])

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
f0 - output values at the current point

Note#

We are using a first order FEM model for the weak form: \int_\Omega \phi f_0(u, u_t, \nabla u, x, t) + \nabla\phi \cdot {\vec f}_1(u, u_t, \nabla u, x, t)