Installation with Anaconda/Miniconda

[1] Download and install Anaconda (or Miniconda if you prefer). Use the Python 3.X version if you have no preference, but either will do.

[2] Open an Anaconda prompt window (Windows) or the Terminal (Mac/Linux).

[3] Create a new environment for pytzer by entering the following:

conda create -n pytzer python=3.6 numpy

[4] Activate the new environment. On Windows:

activate pytzer

On Mac/Linux:

source activate pytzer

You should now see the name of the environment (i.e. pytzer) appear at the very start of each new line in the command window.

[5] Install pytzer into the new environment:

pip install pytzer

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Running pytzer as a "black box"

You can just provide pytzer with a CSV file of temperatures and molality values, and have it return the corresponding activity coefficients in a new CSV file, only having to write the bare minimum in Python, as follows.

[1] Create an input CSV file as described in the import/export documentation - or just save and use the example file pytzerQuickStart.csv.

[2] Open an Anaconda prompt window (Windows) or the Terminal (Mac/Linux) and activate the pytzer environment (installation step [4]).

[3] Navigate to the folder containing the input CSV file (using cd).

[4] Start Python:

python

[5] Import pytzer:

import pytzer as pz

[6] Run pytzer on your input file:

pz.blackbox('pytzerQuickStart.csv')

Once the calculations are complete, a new CSV file will appear, in the same folder as the input file, with the same name as the input file but with _py appended. It contains the input temperature and molality values, followed by the osmotic coefficient (column header: osm), water activity (aw), and then the activity coefficient of each solute (with column headers e.g. gNa for Na⁺ activity coefficient).

The black box function is currently set up to use the MarChemSpec coefficient dictionary. This is based on the model of Waters and Millero (2013), with some additional terms added for tris interactions. It is still under development, so the results will change as pytzer is updated. It contains coefficients for the components: Ca²⁺, Cl⁻, H⁺, HSO₄⁻, K⁺, Mg²⁺, MgOH⁺, Na⁺, OH⁻, SO₄⁻, tris, and trisH⁺. If you have any ions in your input file that are not on this list, then pytzer should still work (as long the charges on those ions are defined in props.charges), but all interaction coefficients involving those ions will be set to zero.

[7] To exit Python, and return to the Anaconda prompt or Terminal:

exit()

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Updating pytzer

[1] Open an Anaconda prompt window (Windows) or the Terminal (Mac/Linux) and activate the pytzer environment (installation step [4]).

[2] Update pytzer with pip:

pip install pytzer --upgrade --no-cache-dir