Compute jacobian at point (no quadrature point)

[Felix Lorenz]

Hi everyone,

I want to compute the transformation of a gradient at a point (no quadrature point) on the reference cell to the real space. Mathematically formulated I want to compute:

How do I get the inverse Jacobian at this point?

Best regards,

Felix

[Weixiong Zheng]

Felix,

Would you take a look at if [1] is what you want to have?

[1]: https://www.dealii.org/8.4.0/doxygen/deal.II/classFEValuesBase.html#a665ab681011424cb1b0ba11c4155a121

Best,

Weixiong

在 2017年6月13日星期二 UTC-7上午9:35:09，Felix Lorenz写道：

[luca.heltai]

Felix,

also, if the point you want is not a quadrature point, you can exploit the following trick:

Point<dim> my_point_in_reference_cell;

std::vector<Point<dim> > quad(1, my_point_in_reference_cell);

and then you can initialize an

FEValues<dim> fev(fe, quad, update_inverse_jacobians);

This will give you access to what you need by


fev.reinit(cell);
auto &jac_invs = fev.get_inverse_jacobians();

Best,
Luca.

> On 14 Jun 2017, at 2:20, Weixiong Zheng <zwxn...@gmail.com> wrote:
>
> Felix,
>
> Would you take a look at if [1] is what you want to have?
>
> [1]: https://www.dealii.org/8.4.0/doxygen/deal.II/classFEValuesBase.html#a665ab681011424cb1b0ba11c4155a121
>
> Best,
> Weixiong
>
> 在 2017年6月13日星期二 UTC-7上午9:35:09，Felix Lorenz写道：
>
> Hi everyone,
>
> I want to compute the transformation of a gradient at a point (no quadrature point) on the reference cell to the real space. Mathematically formulated I want to compute:
>
>
>
>
>
>
>

> How do I get the inverse Jacobian at this point?
>
>
>
> Best regards,
>
> Felix
>
>

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[Felix Lorenz]

Thank you very much. This is exactly what I wanted.

Best regards,

Felix