# [Getdp] Concatenation of field operators

**Thomas_W**
e0208228 at student.tuwien.ac.at

*Mon Oct 15 15:02:52 CEST 2012*

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