The OPAL Discussion Forum

[Philippe Piot <philippe.piot AT gmail.com>]

Pedro, Christos,

  Ah I see! Thank  you for the clarification. All the best, — Philippe. 

On Fri, Nov 19, 2021 at 1:09 AM Christof Metzger-Kraus <christof.j.kraus AT gmail.com> wrote:

Hi Philippe,

before version 2021.1 Opal accepted strings argument with quotation marks and without. Therefore it couldn’t distinguish between a string and a variable name. With 2021.1 we changed this such that strings attributes have to be enclosed in quotation marks. Strings without quotation marks are treated as variable names. In order not to break every input file we added strings constants such as GS which also has the value “GS”. 

GS stands for Gauss-Seidel and is used in the multi grid field solver.

Christof

Philippe Piot <philippe.piot AT gmail.com> schrieb am Fr. 19. Nov. 2021 um 00:47:

Dear All,

  Is there anything special to the "GS" string in OPAL-2021.1? I have a beamline call GS something as simple as 

GS:  Line = (GUN,DR1); 

 OPAL would not run and gives the error

Error{6}>
Error{6}> *** User error detected by function "OpalData::define()"
Error{6}>     You cannot replace the object "GS".
Error{6}>     You cannot replace the object "GS".

After fiddling around I decided to rename the beamline GS1 and everything worked fine! From the source, I could not figure out why "GS" is giving this error. 

  Thank you, -- Philippe. 

PS: and this works fine with OPAL-2.4