# PetscDTPTrimmedEvalJet
Evaluate the jet (function and derivatives) of a basis of the trimmed polynomial k-forms up to a given degree. 
## Synopsis
```
#include "petscdt.h" 
PetscErrorCode PetscDTPTrimmedEvalJet(PetscInt dim, PetscInt npoints, const PetscReal points[], PetscInt degree, PetscInt formDegree, PetscInt jetDegree, PetscReal p[])
```

## Input Parameters

- ***dim -*** the number of variables in the multivariate polynomials
- ***npoints -*** the number of points to evaluate the polynomials at
- ***points -*** [npoints x dim] array of point coordinates
- ***degree -*** the degree (sum of degrees on the variables in a monomial) of the trimmed polynomial space to evaluate.
There are ((dim + degree) choose (dim + formDegree)) x ((degree + formDegree - 1) choose (formDegree)) polynomials in this space.
(You can use `PetscDTPTrimmedSize()` to compute this size.)
- ***formDegree -*** the degree of the form
- ***jetDegree -*** the maximum order partial derivative to evaluate in the jet.  There are ((dim + jetDegree) choose dim) partial derivatives
in the jet.  Choosing jetDegree = 0 means to evaluate just the function and no derivatives



## Output Parameters

- ***p -*** an array containing the evaluations of the PKD polynomials' jets on the points.  The size is
`PetscDTPTrimmedSize()` x ((dim + formDegree) choose dim) x ((dim + k) choose dim) x npoints,
which also describes the order of the dimensions of this
four-dimensional array:
the first (slowest varying) dimension is basis function index;
the second dimension is component of the form;
the third dimension is jet index;
the fourth (fastest varying) dimension is the index of the evaluation point.





## Notes
The ordering of the basis functions is not graded, so the basis functions are not nested by degree like `PetscDTPKDEvalJet()`.
The basis functions are not an L2-orthonormal basis on any particular domain.

The implementation is based on the description of the trimmed polynomials up to degree r as
the direct sum of polynomials up to degree (r-1) and the Koszul differential applied to
homogeneous polynomials of degree (r-1).


## See Also
 `PetscDTPKDEvalJet()`, `PetscDTPTrimmedSize()`

## Level
advanced

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


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