# PetscGaussLobattoLegendreIntegrate
Compute the L2 integral of a function on the GLL points 
## Synopsis
```
#include "petscdt.h" 
PetscErrorCode PetscGaussLobattoLegendreIntegrate(PetscInt n, PetscReal *nodes, PetscReal *weights, const PetscReal *f, PetscReal *in)
```
Not Collective


## Input Parameters

- ***n -*** the number of GLL nodes
- ***nodes -*** the GLL nodes
- ***weights -*** the GLL weights
- ***f -*** the function values at the nodes



## Output Parameter

- ***in -*** the value of the integral





## See Also
 `PetscDTGaussLobattoLegendreQuadrature()`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/dt/interface/dt.c.html#PetscGaussLobattoLegendreIntegrate">src/dm/dt/interface/dt.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex68.c.html">src/ksp/ksp/tutorials/ex68.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex69.c.html">src/ksp/ksp/tutorials/ex69.c.html</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/dm/dt/interface/dt.c)


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