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Web app

Open the web app →

The web app runs discopt.speciation in your browser. You can:

  • pick a bundled database;
  • choose elements or valence states, and the minerals and gases that may form;
  • set amounts, temperature, pH, pe, fixed activities, a charge-balance ion and the activity model.

It then shows results in five tabs:

tab shows
Speciation molalities, activities and activity coefficients; saturation indices; the phases present; the text summary
Sweep species, solids, saturation indices and pH along pH, pe, temperature, an amount, a partial pressure or a fixed activity (CSV export)
Pourbaix / predominance the dominant species or solid of an element on a grid of two variables, with the water stability lines and an Eh axis
log K(T) dissolution constants of the selected phases against temperature
Python the same calculation as a Python script

Sharing. The address bar holds the whole setup, so a copied link reproduces it.

How it works

Nothing is computed on a server. The page loads, in a Web Worker:

  • Pyodide 0.28.3 (CPython compiled to WebAssembly), with numpy, scipy and pydantic;
  • the WebAssembly build of the pounce NLP solver;
  • the Python sources of discopt and of this package, with its databases.

Same algorithm as the package. The equilibrium calculation is the one the Python package does: - speciation; - the complementarity homotopy; - the active-set polish, solved with discopt and pounce.

Warm starts. Sweeps and diagrams start each point from the previous solution.

First load. The first visit downloads about 30 MB, which the browser then caches. A single equilibrium takes a fraction of a second, and a 25 × 25 Pourbaix grid takes 10–30 s.

Limitations. Everything the Python API offers beyond the form (your own reactions, solid solutions, exchangers, surfaces, fitting, optimization) needs the Python package; see the Quick start.

Stopping. A long run can be stopped. The stop restarts Python, which takes a few seconds.

Building

The app's sources are in docs/app/:

  • index.html, app.js, app.css: the page;
  • worker.js: loads Python;
  • web_backend.py: the JSON functions the page calls.

At mkdocs build, a hook in docs_hooks.py writes site/app/py/. It contains: - a zip of discopt's Python sources, at the version in uv.lock; - a zip of this package; - the pounce wheel; - a manifest.

Downloads are cached in .cache/webapp/.