Merge pull request #1948 from dlakaplan/tzrwarn

Warning when setting TZRMJD, method to set phase offset to 0

Author: abhisrkckl

CHANGELOG-unreleased.md

@@ -12,5 +12,7 @@ the released changes.
 ### Added
 - Anderson-Darling test for normal data with fixed mean/variance
 - KS test to check if the whitened residuals are unit-normal distributed
+- Warning about setting of TZRMJD from TOAs
+- Method to zero out mean residual based on TZRMJD
 ### Fixed
 ### Removed

src/pint/models/absolute_phase.py

@@ -137,5 +137,8 @@ def make_TZR_toa(self, toas):
         later = [i for i in toas.get_mjds() if i > PEPOCH * u.d]
         earlier = [i for i in toas.get_mjds() if i <= PEPOCH * u.d]
         TZRMJD = min(later) if later else max(earlier)
+        log.warning(
+            f"TZRMJD is not set.  Setting TZRMJD to first TOA after PEPOCH or last TOA before PEPOCH.  This may leave your residuals with an offset."
+        )
         self.TZRMJD.quantity = TZRMJD.value
         self.setup()

src/pint/residuals.py

@@ -500,6 +500,17 @@ def calc_time_mean(
         """
         return self._calc_mean(weighted, "time", calctype=calctype)
 
+    def zero_TZR(self, use_weighted_mean: Optional[bool] = True) -> None:
+        """
+        Remove any net offset from the TOAs by subtracting the mean residual from TZRMJD
+
+        Parameters
+        ----------
+        use_weighted_mean : bool or None, optional
+            Whether to use weighted mean for mean subtraction.
+        """
+        self.model.TZRMJD.quantity += self.calc_time_mean(weighted=use_weighted_mean)
+
     def calc_time_resids(
         self,
         calctype: Literal["taylor", "modelF0", "numerical"] = "taylor",

tests/test_absphase.py

@@ -2,8 +2,11 @@
 import os
 import pytest
 
+from astropy import units as u
 import pint.models
 import pint.toa
+import pint.residuals
+import pint.simulation
 from pinttestdata import datadir
 
 parfile = os.path.join(datadir, "NGC6440E.par")
@@ -28,3 +31,14 @@ def test_tzr_attr():
 
     assert not toas.tzr
     assert model.components["AbsPhase"].get_TZR_toa(toas).tzr
+
+
+def test_zero_TZR():
+    model = pint.models.get_model(parfile)
+    toas = pint.simulation.make_fake_toas_uniform(50000, 51000, 20, model=model)
+    toas.adjust_TOAs(10 * u.s)
+    r = pint.residuals.Residuals(toas, model)
+    assert r.calc_time_mean() > 9 * u.s
+    r.zero_TZR()
+    r.update()
+    assert r.calc_time_mean() < 1 * u.ms