[Getdp] FW: Concatenation of field operators

[michael.asam at infineon.com]

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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