# PetscDTReconstructPoly
create matrix representing polynomial reconstruction using cell intervals and evaluation at target intervals 
## Synopsis
```
#include "petscdt.h" 
PetscErrorCode PetscDTReconstructPoly(PetscInt degree, PetscInt nsource, const PetscReal *sourcex, PetscInt ntarget, const PetscReal *targetx, PetscReal *R)
```
Not Collective


## Input Parameters

- ***degree -*** degree of reconstruction polynomial
- ***nsource -*** number of source intervals
- ***sourcex -*** sorted coordinates of source cell boundaries (length nsource+1)
- ***ntarget -*** number of target intervals
- ***targetx -*** sorted coordinates of target cell boundaries (length ntarget+1)



## Output Parameter

- ***R -*** reconstruction matrix, utarget = sum_s R[t*nsource+s] * usource[s]





## See Also
 `PetscDTLegendreEval()`

## Level
advanced

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


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


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