PetscDSGetJacobianPreconditioner#

Get the pointwise Jacobian preconditioner function for given test and basis field. If this is missing, the system matrix is used to build the preconditioner.

Synopsis#

#include "petscds.h" 
PetscErrorCode PetscDSGetJacobianPreconditioner(PetscDS ds, PetscInt f, PetscInt g, void (**g0)(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, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g0[]), void (**g1)(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, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g1[]), void (**g2)(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, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g2[]), void (**g3)(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, PetscReal u_tShift, const PetscReal x[], PetscInt numConstants, const PetscScalar constants[], PetscScalar g3[]))

Not Collective

Input Parameters#

  • ds - The PetscDS

  • f - The test field number

  • g - The field number

Output Parameters#

  • g0 - integrand for the test and basis function term

  • g1 - integrand for the test function and basis function gradient term

  • g2 - integrand for the test function gradient and basis function term

  • g3 - integrand for the test function gradient and basis function gradient term

Calling sequence of g0, g1, g2 and g3#

  void g0(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 u_tShift, const PetscReal x[], PetscScalar g0[])

  • 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

  • u_tShift - the multiplier a for dF/dU_t

  • x - coordinates of the current point

  • numConstants - number of constant parameters

  • constants - constant parameters

  • g0 - output values at the current point

Note#

We are using a first order FEM model for the weak form#

\int_\Omega \phi g_0(u, u_t, \nabla u, x, t) \psi + \phi {\vec g}_1(u, u_t, \nabla u, x, t) \nabla \psi + \nabla\phi \cdot {\vec g}_2(u, u_t, \nabla u, x, t) \psi + \nabla\phi \cdot {\overleftrightarrow g}_3(u, u_t, \nabla u, x, t) \cdot \nabla \psi

See Also#

PetscDS, PetscDSSetJacobianPreconditioner(), PetscDSGetJacobian()

Level#

intermediate

Location#

src/dm/dt/interface/dtds.c

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