PetscDSSetJacobianPreconditioner#

Set the pointwise Jacobian function for given test and basis fields that constructs the matrix used to compute the preconditioner. If this is missing, the system matrix is used to build the preconditioner.

Synopsis#

#include "petscds.h" 
PetscErrorCode PetscDSSetJacobianPreconditioner(PetscDS ds, PetscInt f, PetscInt g, PetscPointJacFn *g0, PetscPointJacFn *g1, PetscPointJacFn *g2, PetscPointJacFn *g3)

Not Collective

Input Parameters#

ds - The PetscDS
f - The test field number
g - The field number
g0 - integrand for the test and basis function term, see PetscPointJacFn
g1 - integrand for the test function and basis function gradient term, see PetscPointJacFn
g2 - integrand for the test function gradient and basis function term, see PetscPointJacFn
g3 - integrand for the test function gradient and basis function gradient term, see PetscPointJacFn

Note#

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

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

Developer Note#

The name is confusing since the function computes a matrix used to construct the preconditioner, not a preconditioner.

Level#

intermediate

Location#

src/dm/dt/interface/dtds.c

Examples#

src/snes/tutorials/ex64.c
src/snes/tutorials/ex69.c
src/snes/tutorials/ex62.c

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