:orphan:
# DMPlexLandauIJacobian
TS Jacobian construction, confusingly this adds mass
## Synopsis
```
#include "petscdmplex.h"
#include "petsclandau.h"
PetscErrorCode DMPlexLandauIJacobian(TS ts, PetscReal time_dummy, Vec X, Vec U_tdummy, PetscReal shift, Mat Amat, Mat Pmat, void *actx)
```
Collective
## Input Parameters
- ***TS -*** The time stepping context
- ***time_dummy -*** current time (not used)
- ***X -*** Current state
- ***U_tdummy -*** Time derivative of current state (not used)
- ***shift -*** shift for du/dt term
- ***actx -*** Landau context
## Output Parameters
- ***Amat -*** Jacobian
- ***Pmat -*** same as Amat
.keywords: mesh
## See Also
`DMPlexLandauCreateVelocitySpace()`, `DMPlexLandauIFunction()`
## Level
beginner
## Location
src/ts/utils/dmplexlandau/plexland.c
## Examples
src/ts/utils/dmplexlandau/tutorials/ex1.c
src/ts/utils/dmplexlandau/tutorials/ex1f90.F90
src/ts/utils/dmplexlandau/tutorials/ex2.c
---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ts/utils/dmplexlandau/plexland.c)
[Index of all LANDAU routines](index.md)
[Table of Contents for all manual pages](/manualpages/index.md)
[Index of all manual pages](/manualpages/singleindex.md)