# 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 on ts


## 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
.seealso: `DMPlexLandauCreateVelocitySpace()`, `DMPlexLandauIFunction()`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/utils/dmplexlandauplexland.c.html#DMPlexLandauIJacobian">src/ts/utils/dmplexlandauplexland.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/utils/dmplexlandau/tutorials/ex1.c.html">src/ts/utils/dmplexlandau/tutorials/ex1.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/utils/dmplexlandau/tutorials/ex1f90.F90.html">src/ts/utils/dmplexlandau/tutorials/ex1f90.F90.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/utils/dmplexlandau/tutorials/ex2.c.html">src/ts/utils/dmplexlandau/tutorials/ex2.c.html</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ts/utils/dmplexlandauplexland.c)


[Index of all LANDAU routines](index.md)  
[Table of Contents for all manual pages](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
