[Getdp] divergence in post-processing

michael.asam at infineon.com michael.asam at infineon.com
Wed Nov 13 07:32:39 CET 2013

Hi Andre,

for the postprocessing itself I suppose there is no possibility to
take two times the derivative (Div-Grad). But there are at least two other
You can calculate the divergence in a separate resolution (this could 
be time consuming for large problems) or you can calculate the divergence
in Gmsh via the plugin Divergence (menu Tools->Plugins).
Please be aware that in order to calculate two time the derivative
you need at least 2nd order basisfunctions for v.

Best regards,

-----Original Message-----
From: getdp-bounces at ace20.montefiore.ulg.ac.be [mailto:getdp-bounces at ace20.montefiore.ulg.ac.be] On Behalf Of Andre Antunes
Sent: Tuesday, November 12, 2013 1:06 PM
To: getdp at geuz.org
Subject: [Getdp] divergence in post-processing


I am probably missing something obvious.
In postprocessing I would like to calculate the norm of the electric field and the divergence of the electric field

Quantity {
  {Name normE; Value {Local { [ Norm[-{Grad v}-dadt[]] ]; In Omega; Jacobian Volume;}}}
  {Name charge; Value {Local {[ Div[-{Grad v}-dadt[]]   ]; In Omega; Jacobian Volume;}}}

The first line works perfectly.
I am not able to calculate the divergence in the second line. 
Tried Div(), Div[], {Div ()}. Couldn't find examples either. Would anyone be kind enough to tell where the problem is?

Best regards, 

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