Remove getter

Author: harveydevereux

janus_core/helpers/observables.py

@@ -17,28 +17,23 @@ class Observable:
     ----------
     dimension : int
         The dimension of the observed data.
-    getter : Optional[callable]
-        An optional callable to construct the Observable from.
     """
 
-    def __init__(self, dimension: int = 1, *, getter: Optional[callable] = None):
+    def __init__(self, dimension: int = 1):
         """
         Initialise an observable with a given dimensionality.
 
         Parameters
         ----------
         dimension : int
             The dimension of the observed data.
-        getter : Optional[callable]
-            An optional callable to construct the Observable from.
         """
         self._dimension = dimension
-        self._getter = getter
         self.atoms = None
 
     def __call__(self, atoms: Atoms, *args, **kwargs) -> list[float]:
         """
-        Call the user supplied getter if it exits.
+        Signature for returning observed value from atoms.
 
         Parameters
         ----------
@@ -53,18 +48,7 @@ def __call__(self, atoms: Atoms, *args, **kwargs) -> list[float]:
         -------
         list[float]
             The observed value, with dimensions atoms by self.dimension.
-
-        Raises
-        ------
-        ValueError
-            If user supplied getter is None.
         """
-        if self._getter:
-            value = self._getter(atoms, *args, **kwargs)
-            if not isinstance(value, list):
-                return [value]
-            return value
-        raise ValueError("No user getter supplied")
 
     @property
     def dimension(self):

tests/test_correlator.py

@@ -3,7 +3,6 @@
 from collections.abc import Iterable
 from pathlib import Path
 
-from ase import Atoms
 from ase.io import read
 from ase.units import GPa
 import numpy as np
@@ -15,7 +14,6 @@
 from janus_core.calculations.single_point import SinglePoint
 from janus_core.helpers import post_process
 from janus_core.helpers.correlator import Correlator
-from janus_core.helpers.janus_types import Observable
 from janus_core.helpers.observables import Stress, Velocity
 
 DATA_PATH = Path(__file__).parent / "data"
@@ -146,15 +144,6 @@ def test_md_correlations(tmp_path):
         calc_kwargs={"model": MODEL_PATH},
     )
 
-    def user_observable_a(atoms: Atoms, kappa, *, gamma) -> float:
-        """User specified getter for correlation."""
-        return (
-            gamma
-            * kappa
-            * atoms.get_stress(include_ideal_gas=True, voigt=True)[-1]
-            / GPa
-        )
-
     nve = NVE(
         struct=single_point.struct,
         temp=300.0,
@@ -164,15 +153,6 @@ def user_observable_a(atoms: Atoms, kappa, *, gamma) -> float:
         stats_every=1,
         file_prefix=file_prefix,
         correlation_kwargs=[
-            {
-                "a": (Observable(1, getter=user_observable_a), (2,), {"gamma": 2}),
-                "b": Stress([("xy")]),
-                "name": "user_correlation",
-                "blocks": 1,
-                "points": 11,
-                "averaging": 1,
-                "update_frequency": 1,
-            },
             {
                 "a": Stress([("xy")]),
                 "b": Stress([("xy")]),
@@ -195,8 +175,7 @@ def user_observable_a(atoms: Atoms, kappa, *, gamma) -> float:
     assert cor_path.exists()
     with open(cor_path, encoding="utf8") as in_file:
         cor = load(in_file, Loader=Loader)
-    assert len(cor) == 2
-    assert "user_correlation" in cor
+    assert len(cor) == 1
     assert "stress_xy_auto_cor" in cor
 
     stress_cor = cor["stress_xy_auto_cor"]
@@ -206,11 +185,3 @@ def user_observable_a(atoms: Atoms, kappa, *, gamma) -> float:
     direct = correlate(pxy, pxy, fft=False)
     # input data differs due to i/o, error is expected 1e-5
     assert direct == approx(value, rel=1e-5)
-
-    user_cor = cor["user_correlation"]
-    value, lags = user_cor["value"], stress_cor["lags"]
-    assert len(value) == len(lags) == 11
-
-    direct = correlate([v * 4.0 for v in pxy], pxy, fft=False)
-    # input data differs due to i/o, error is expected 1e-5
-    assert direct == approx(value, rel=1e-5)