add minimal test for oxy evo

Author: esoteric-ephemera

.pre-commit-config.yaml

@@ -39,4 +39,4 @@ repos:
       - id: codespell
         stages: [pre-commit, commit-msg]
         exclude_types: [json, bib, svg]
-        args: [--ignore-words-list, "mater,fwe,te"]
+        args: [--ignore-words-list, "mater,fwe,te,alo"]

mp_api/client/core/_oxygen_evolution.py

@@ -5,6 +5,7 @@
 from collections.abc import Sequence
 from io import StringIO
 from pathlib import Path
+from warnings import warn
 
 import numpy as np
 import pandas as pd
@@ -29,7 +30,7 @@ class OxygenEvolution:
 
     def __init__(
         self,
-        cache_file: Path | None = None,  # DEFAULT_CACHE_FILE,
+        cache_file: Path | None = DEFAULT_CACHE_FILE,
     ):
         self._spline_pars = None
         self.cache_file = cache_file
@@ -57,9 +58,6 @@ def get_chempot_temp_data(
         meas_p : float
             The O2 partial pressure at which the experimental data was collected.
             Per NIST, this is 0.1 MPa
-        mu_o2_ref : float | None = None
-            If a float, the O2 chemical potential at 0K.
-            If None, this is determined from MP's data.
 
         Returns:
         -----------
@@ -96,11 +94,10 @@ def get_chempot_temp_data(
 
         return temp_K, mu_mu0
 
-    @property
     def mu_to_temp_spline_params(self):
         if self._spline_pars is None:
-            temp, mu_m0 = self.get_chempot_temp_data()
-
+            temp = np.array(NIST_JANAF_O2_MU_T["temperature"])
+            mu_m0 = np.array(NIST_JANAF_O2_MU_T["mu-mu_0K"])
             # spline needs the x vars to be in increasing order
             mu_sort_idx = np.argsort(mu_m0)
             self._spline_pars = make_splrep(mu_m0[mu_sort_idx], temp[mu_sort_idx])
@@ -117,7 +114,17 @@ def mu_to_temp_spline(
         mu : np.ndarray
             The O2 chemical potentials to sample at.
         """
-        return splev(np.array(mu), self.mu_to_temp_spline_params)
+        mu_arr = np.array(mu)
+        if np.any(
+            (mu_arr < min(NIST_JANAF_O2_MU_T["mu-mu_0K"]))
+            | (mu_arr > max(NIST_JANAF_O2_MU_T["mu-mu_0K"]))
+        ):
+            warn(
+                "Some of the input chemical potential values are "
+                "outside the fitting range - extrapolation will be inaccurate.",
+                stacklevel=2,
+            )
+        return splev(mu_arr, self.mu_to_temp_spline_params())
 
     @staticmethod
     def stairstep(x, y, z):
@@ -196,3 +203,146 @@ def get_oxygen_evolution_from_phase_diagram(
                 data["mu"] - mu_0K
             )
         return oxy_evo_data
+
+
+# This data is generated by running:
+# `OxygenEvolution().get_chempot_temp_data()`
+# The contents of `DEFAULT_CACHE_FILE` will contain this data.
+# Because the last update of the JANAF tables was in 1998
+# (writing in 2025), we see no need to dynamically retrieve this data
+NIST_JANAF_O2_MU_T = {
+    "mu-mu_0K": [
+        0.0,
+        -0.15766752295964667,
+        -0.35716109254410505,
+        -0.4633062592086276,
+        -0.5684747265209704,
+        -0.5725679617587883,
+        -0.6845046823072302,
+        -0.7988365855732343,
+        -0.9153600136580551,
+        -1.0338982557640533,
+        -1.2764843857253183,
+        -1.5256155519745132,
+        -1.7804988878829335,
+        -2.0404658980577506,
+        -2.304982822611666,
+        -2.5736050343764276,
+        -2.8459749660488933,
+        -3.1217816895393757,
+        -3.4007764623761245,
+        -3.6827416348963578,
+        -3.9674927231001944,
+        -4.254892918628172,
+        -4.544805413120827,
+        -4.837112053904078,
+        -5.13170297971957,
+        -5.428488021421295,
+        -5.7273687184475115,
+        -6.028299468011739,
+        -6.3311932102488635,
+        -6.635957703158943,
+        -6.9425981288768055,
+        -7.2509807883238855,
+        -7.561092207949628,
+        -7.872879529978791,
+        -8.186271240950743,
+        -8.501236248056516,
+        -8.817722729947826,
+        -9.135721358781987,
+        -9.4551295282894,
+        -9.775953457031855,
+        -10.098137177953216,
+        -10.421667217502918,
+        -10.746499009321454,
+        -11.072592132757157,
+        -11.399910312866226,
+        -11.728421420412731,
+        -12.058141001801161,
+        -12.389003762132672,
+        -12.720990009294923,
+        -13.05408419688343,
+        -13.388322599841986,
+        -13.723603648327966,
+        -14.059921123779567,
+        -14.397323738264184,
+        -14.735764852568353,
+        -15.075250685253877,
+        -15.415683812185982,
+        -15.757182386038748,
+        -16.099653128385278,
+        -16.44311262205701,
+        -16.787639635503336,
+        -17.13308492324121,
+        -17.47953139942788,
+        -17.826947971254377,
+        -18.175365731529666,
+    ],
+    "temperature": [
+        0.0,
+        100.0,
+        200.0,
+        250.0,
+        298.15,
+        300.0,
+        350.0,
+        400.0,
+        450.0,
+        500.0,
+        600.0,
+        700.0,
+        800.0,
+        900.0,
+        1000.0,
+        1100.0,
+        1200.0,
+        1300.0,
+        1400.0,
+        1500.0,
+        1600.0,
+        1700.0,
+        1800.0,
+        1900.0,
+        2000.0,
+        2100.0,
+        2200.0,
+        2300.0,
+        2400.0,
+        2500.0,
+        2600.0,
+        2700.0,
+        2800.0,
+        2900.0,
+        3000.0,
+        3100.0,
+        3200.0,
+        3300.0,
+        3400.0,
+        3500.0,
+        3600.0,
+        3700.0,
+        3800.0,
+        3900.0,
+        4000.0,
+        4100.0,
+        4200.0,
+        4300.0,
+        4400.0,
+        4500.0,
+        4600.0,
+        4700.0,
+        4800.0,
+        4900.0,
+        5000.0,
+        5100.0,
+        5200.0,
+        5300.0,
+        5400.0,
+        5500.0,
+        5600.0,
+        5700.0,
+        5800.0,
+        5900.0,
+        6000.0,
+    ],
+}

tests/core/test_oxygen_evolution.py

@@ -0,0 +1,68 @@
+"""Test the oxygen evolution analysis features in the client."""
+
+import pytest
+import numpy as np
+from scipy.interpolate import splev
+
+from pymatgen.analysis.phase_diagram import PhaseDiagram
+from pymatgen.core import Composition
+from pymatgen.entries.computed_entries import ComputedEntry
+
+from mp_api.client.core._oxygen_evolution import NIST_JANAF_O2_MU_T, OxygenEvolution
+
+
+def test_interp():
+    oxyevo = OxygenEvolution()
+
+    # Spline interpolation is exact for all fit points:
+    assert np.allclose(
+        oxyevo.mu_to_temp_spline(np.array(NIST_JANAF_O2_MU_T["mu-mu_0K"])),
+        NIST_JANAF_O2_MU_T["temperature"],
+    )
+
+    # mu(T) is a generally decreasing function, at least for fit range
+    deriv = splev(
+        np.linspace(
+            min(NIST_JANAF_O2_MU_T["mu-mu_0K"]),
+            max(NIST_JANAF_O2_MU_T["mu-mu_0K"]),
+            1000,
+        ),
+        oxyevo.mu_to_temp_spline_params(),
+        der=1,
+    )
+    assert len(deriv[deriv > 0]) == 0
+
+    # ensure user is warned when data is outside fit range
+    for badval in (1.0, -50.0):
+        with pytest.warns(UserWarning, match="outside the fitting range"):
+            oxyevo.mu_to_temp_spline(badval)
+
+
+def test_oxy_evo():
+    """Very fake Al-O chemical system for testing purposes."""
+    entries = [
+        ComputedEntry({"Al": 1}, -2.0),
+        ComputedEntry({"O": 1}, -5.0),
+        ComputedEntry({"Al": 1, "O": 1}, -25.0),
+        ComputedEntry({"Al": 2, "O": 3}, -55.0),
+        ComputedEntry({"Al": 3, "O": 2}, -5.0),
+    ]
+    phase_diag = PhaseDiagram(entries)
+
+    ref_comp = Composition({"Al": 4, "O": 1})
+    evo = OxygenEvolution().get_oxygen_evolution_from_phase_diagram(
+        phase_diag, [ref_comp]
+    )
+    assert ref_comp.formula in evo
+    assert np.allclose(evo[ref_comp.formula]["evolution"], [0.5, 0.5, -1.5])
+    assert np.allclose(evo[ref_comp.formula]["temperature"], [5949.70500942, 0.0, 0.0])
+    assert all(
+        str(evo[ref_comp.formula]["reaction"][idx]) == rxn
+        for idx, rxn in enumerate(
+            [
+                "2 Al4O -> 8 Al + O2",
+                "2 Al4O -> 8 Al + O2",
+                "2 Al4O + 3 O2 -> 8 AlO",
+            ]
+        )
+    )