invriant point of Natron and Halite

[Helge]

This is an interesting case. Using GWB and the attached rea-script the equilibrium is found. Translating to python and running again the equilibrium is found, too. But the calculation has to be killed manually, the attached log-file has 44 MB. Addmittedly, it is a tricky calculation because SI of Na2CO3:7H2O(s) is -0.0065 at this point, also pretty much close to saturation. 

I wonder whether the command epsilon = 5e-6 is correctly transferred using python.

Best regards,

Helge

gwb.zip

[Jia Wang]

Hello Helge, 

This is a strange issue. I ran your python input file and didn't have problems with the run ending automatically when the calculation was completed. My output file agrees with the output file you provided (0081_GWB.log) and the results from 0081.rea, so I do think your script is running to completion. 

Perhaps the issue is related to how your python scripts are run? Are you encountering any of these issues with your other GWB plugin scripts as well? Do you use the windows command prompt to run the script?

With some GWB programs, you can limit the maximum computing time by setting the variable "cpu_max". You can find more information about this in the GWB Command Reference guide. Could you try setting this in your script to see if python will terminate at the allotted time? You shouldn't need to set this to end a regular run, but it can be a good temporary solution for the issue at hand. 

With regards to epsilon, I tested by resetting the python and react script to the default values and the run would not run to completion. I do believe the change in epsilon input is being accounted for. 

Hope this helps,
Jia Wang
Aqueous Solutions LLC

[Helge]

Hello Jia,

this is number 81 in a series of calculations, run in a normal windows command prompt. At number 81 the output in the prompt stopped. But indeed, if I wait long enough, the calculation converges. 

Please excuse my impatience. 🙂

In fact, we encounter numerical problems every once in a while, but usually epsilon, delxi, or pickup entire are our friends. 

Best regards,

Helge