PHREEQCRM error

[Yongqiang]

Hi Phreeqc experts,

I am compiling Phreeqcrm to simulate reactive transport. However, I used a simple solution composition with only Na and Cl. It popped out a strange error as the following:

ERROR:               Oxygen Mass of oxygen has not converged.   Residual: 0.000000e+00

Any comments for this error?

Thanks,
Michael

[dlparkhurst]

Hard to say what is wrong.

Possibly you are using a very large volume of water for a cell. PHREEQC works best if the volumes are between 0.01 and 10 liters of water.

Another possibility is that your transport solution is not accurate enough for H and O.

PHREEQC will work better if you use charge balanced solutions.

[Yongqiang]

Hi David,

Thanks for the instruction. I'll double check my code.

By the way, I carefully checked the case in the Tests folder distributed with the PHREEQCRM. I found that it seems that the variable *volume* and *sat_calc* were create through (double *) malloc((size_t) (nxyz * sizeof(double))); in the void advection_c() function. However, it seems they are not freed at the end of this function. Please see the file advection_c.c

Thanks,
Michael

[dlparkhurst]

Yes, you are correct, the arrays should be freed. I'll make the change for the next version.

However, we are working on some enhancements for PhreeqcRM, and I think it is unlikely we will update the C version. There are just too many wrappers to write and documentation to update. If you want to use the new features, you will have to use C++, Fortran, or Python. There really is no advantage to C because it only wraps C++; you might as well use C++ and avoid the mistakes like the one I made not freeing an array.

[Yongqiang]

Thank you, David.

I used C because C is my first programming language learned in Uni. I'll transfer the C++ for my next version. By the way, you mentioned Python version. Do you mean to run PHREEQCRM with Python or IPHREEQC?

Regards,
Michael

[dlparkhurst]

We are working on Python bindings for PhreeqcRM. Not sure whether we will do IPhreeqc or not.