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Ms. Rachel Rotz

Ms. Rachel Rotz

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Hi All,

I have a model in Visual Modflow Classic and trying to run WinPEST using concentration values in the objective function. 
When I used head values as the objective function to estimate parameters with PEST, it ran fine. But when I use only concentration values, I keep getting an error:
"Cannot open model output file "projectname.001.COB."
I am running everything as an administrator and cannot even find a .COB file on my computer. 
I've uninstalled and reinstalled the program, tried different versions of the models, and even changed the number of concentration observations to reduce complexity. I can't get PEST to run.
Anyone ever see this error or have recommendations on what to do?
Thanks so much!
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  • 4 weeks later...

Hi Rachel,

The problem is probably that the concentration observation file is not generated after your model finishes. Therefore PEST complains that it cannot find it. The reasons for this could be many. I suggest you to study how model equivalent concentration observations are generated with VM. Alternatively, you could do it manualy with MOD2OBS program from PEST utility suit for instance. When not sure what to do, read PEST manual.

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