Merge pull request nanograv#1795 from dlakaplan/implicitpar

Allow setting of parameter quantity/value implicitly

CHANGELOG-unreleased.md

@@ -11,5 +11,6 @@ the released changes.
 ### Changed
 ### Added
 - Type hints in `pint.derived_quantities`
+- Doing `model.par = something` will try to assign to `par.quantity` or `par.value` but will give warning
 ### Fixed
 ### Removed

src/pint/models/timing_model.py

@@ -548,6 +548,16 @@ def __setattr__(self, name, value):
         if isinstance(value, (Parameter, prefixParameter)) and name != value.name:
             for p in ["quantity", "uncertainty", "frozen"]:
                 setattr(getattr(self, name), p, getattr(value, p))
+        elif isinstance(value, (u.Quantity, time.Time)):
+            log.warning(
+                f"Setting '{name}.quantity' to '{value}' although 'quantity' not specified"
+            )
+            getattr(self, name).quantity = value
+        elif isinstance(value, (float, str, bool, int)) and name != "name":
+            log.warning(
+                f"Setting '{name}.value' to '{value}' (assumed units '{getattr(self,name).units}') although 'value' not specified"
+            )
+            getattr(self, name).value = value
         else:
             super().__setattr__(name, value)
 

tests/test_parchange.py

@@ -0,0 +1,45 @@
+from astropy import units as u, constants as c
+from astropy.time import Time
+import numpy as np
+from pint.models import get_model_and_toas
+import pytest
+import os
+from pinttestdata import datadir
+
+
+@pytest.mark.parametrize(
+    "par,newvalue",
+    (
+        ("PLANET_SHAPIRO", True),
+        ("F1", 10 * u.Hz / u.s),
+        ("F0", 20),
+        ("PSR", "ABC-XYZ"),
+        ("POSEPOCH", 53760.0),
+        ("PEPOCH", Time(53760, format="mjd")),
+    ),
+)
+def test_parchange(par, newvalue):
+    m, t = get_model_and_toas(
+        os.path.join(datadir, "NGC6440E.par"), os.path.join(datadir, "NGC6440E.tim")
+    )
+    setattr(m, par, newvalue)
+    if isinstance(newvalue, (u.Quantity, Time)):
+        assert m[par].quantity == newvalue
+    else:
+        assert m[par].value == newvalue
+
+
+@pytest.mark.parametrize(
+    "par,newvalue",
+    (
+        ("F1", 10 * u.Hz / u.s**2),
+        ("F0", "abc"),
+    ),
+)
+def test_parchange_fails(par, newvalue):
+    m, t = get_model_and_toas(
+        os.path.join(datadir, "NGC6440E.par"), os.path.join(datadir, "NGC6440E.tim")
+    )
+
+    with pytest.raises((ValueError, u.UnitConversionError)):
+        setattr(m, par, newvalue)