# [Getdp] FW: Concatenation of field operators

**michael.asam at infineon.com**
michael.asam at infineon.com

*Tue Oct 16 08:29:19 CEST 2012*

Hi Thomas,
I think this cannot be done in the post-processing.
Probably one solution would be to calculate the first gradient
in the Formulation{} part by adding a new quantity (e.g. dv)
and do a kind of protection:
Formulation{
...
Galerkin { [ -Norm[{v}], {dv} ]; In All; Integration I1; Jacobian JVol; }
Galerkin { [ Dof{dv}, {dv} ]; In All; Integration I1; Jacobian JVol; }
}
You have to make sure that v has at least 2nd order basis functions
in order to be twice differentiable.
I hope this works :-)
Best regards
Michael
-----Original Message-----
From: getdp-bounces at ace20.montefiore.ulg.ac.be [mailto:getdp-bounces at ace20.montefiore.ulg.ac.be] On Behalf Of Thomas_W
Sent: Monday, October 15, 2012 3:03 PM
To: getdp at geuz.org
Subject: [Getdp] Concatenation of field operators
Dear all,
I try to evaluate the following quantity in the Post-processing part,
where v is the discretized quantity:
|*Grad (|Grad (v)|)|.
*
I tried variants such as:
PostProcessing {
{ Name The; NameOfFormulation f_v;
Quantity {
{ Name jj;
Value{
Local{ [ {d {d v}*{d v} } ] ; In All;Jacobian JVol; }
}
}
}
}
}
or also
Local{ [ {d {Norm[{v}]} } ] ; In All;Jacobian JVol; }.
All these variants yield an error, namely 'syntax error ({)' in the
corresponding line. It probably has to do with the fact that only v,
and not Norm[{v}] is the original discretized quantity.
Do you have a solution how to evaluate such a function with GetDP?
Thank you,
Thomas
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