I split the CalibrationInterpolator

src/ctapipe/io/__init__.py

@@ -18,7 +18,12 @@
 
 from .datawriter import DATA_MODEL_VERSION, DataWriter
 
-from .interpolation import Interpolator, PointingInterpolator, CalibrationInterpolator
+from .interpolation import (
+    Interpolator,
+    PointingInterpolator,
+    GainInterpolator,
+    PedestalInterpolator,
+)
 
 __all__ = [
     "HDF5TableWriter",
@@ -39,5 +44,6 @@
     "get_hdf5_datalevels",
     "Interpolator",
     "PointingInterpolator",
-    "CalibrationInterpolator",
+    "PedestalInterpolator",
+    "GainInterpolator",
 ]

src/ctapipe/io/interpolation.py

@@ -16,6 +16,8 @@ class StepFunction:
 
     """
     Step function Interpolator for the gain and pedestals
+    Interpolates data so that for each time the value from the closest previous
+    point given.
 
     Parameters
     ----------
@@ -80,7 +82,7 @@ class Interpolator(Component, metaclass=ABCMeta):
         default_value=False,
     ).tag(config=True)
 
-    table_location = None
+    telescope_data_group = None
     required_columns = set()
     expected_units = {}
 
@@ -152,7 +154,7 @@ def _check_interpolators(self, tel_id):
     def _read_parameter_table(self, tel_id):
         input_table = read_table(
             self.h5file,
-            f"{self.table_location}/tel_{tel_id:03d}",
+            f"{self.telescope_data_group}/tel_{tel_id:03d}",
         )
         self.add_table(tel_id, input_table)
 
@@ -162,7 +164,7 @@ class PointingInterpolator(Interpolator):
     Interpolator for pointing and pointing correction data
     """
 
-    table_location = "/dl0/monitoring/telescope/pointing"
+    telescope_data_group = "/dl0/monitoring/telescope/pointing"
     required_columns = {"time", "azimuth", "altitude"}
     expected_units = {"azimuth": u.rad, "altitude": u.rad}
 
@@ -228,12 +230,12 @@ def add_table(self, tel_id, input_table):
         self._interpolators[tel_id]["alt"] = interp1d(mjd, alt, **self.interp_options)
 
 
-class CalibrationInterpolator(Interpolator):
+class GainInterpolator(Interpolator):
     """
-    Interpolator for calibration data
+    Interpolator for relative gain data
     """
 
-    table_location = "dl1/calibration"  # TBD
+    telescope_data_group = "dl1/calibration/gain"  # TBD
 
     def __call__(self, tel_id, time):
         """
@@ -248,16 +250,16 @@ def __call__(self, tel_id, time):
 
         Returns
         -------
-        cal : array [float]
-            interpolated calibration quantity
+        gain : array [float]
+            interpolated relative gain
         """
 
         self._check_interpolators(tel_id)
 
-        cal = self._interpolators[tel_id][self.par_name](time)
-        return cal
+        gain = self._interpolators[tel_id]["gain"](time)
+        return gain
 
-    def add_table(self, tel_id, input_table, par_name="pedestal"):
+    def add_table(self, tel_id, input_table):
         """
         Add a table to this interpolator
 
@@ -267,25 +269,74 @@ def add_table(self, tel_id, input_table, par_name="pedestal"):
             Telescope id
         input_table : astropy.table.Table
             Table of pointing values, expected columns
-            are ``time`` as ``Time`` column. The calibration
-            parameter column is given through the variable ``par_name``
-        par_name : str
-            Name of the parameter that is to be interpolated
-            ``pedestal`` is used for pedestals, ``gain`` for gain
-            can also be the name of statistical parameters to
-            interpolate the content of StatisticsContainers
+            are ``time`` as ``Time`` column and "gain"
+            for the relative gain data
+        """
+
+        self.required_columns = {"time", "gain"}
+
+        self._check_tables(input_table)
+
+        input_table.sort("time")
+        time = input_table["time"]
+        gain = input_table["gain"]
+        self._interpolators[tel_id] = {}
+        self._interpolators[tel_id]["gain"] = StepFunction(
+            time, gain, **self.interp_options
+        )
+
+
+class PedestalInterpolator(Interpolator):
+    """
+    Interpolator for Pedestal data
+    """
+
+    telescope_data_group = "dl1/calibration/pedestal"  # TBD
+
+    def __call__(self, tel_id, time):
         """
+        Interpolate pedestal or gain for a given time and tel_id.
 
-        self.par_name = par_name
+        Parameters
+        ----------
+        tel_id : int
+            telescope id
+        time : astropy.time.Time
+            time for which to interpolate the calibration data
+
+        Returns
+        -------
+        pedestal : array [float]
+            interpolated pedestal values
+        """
+
+        self._check_interpolators(tel_id)
+
+        pedestal = self._interpolators[tel_id]["pedestal"](time)
+        return pedestal
+
+    def add_table(self, tel_id, input_table):
+        """
+        Add a table to this interpolator
+
+        Parameters
+        ----------
+        tel_id : int
+            Telescope id
+        input_table : astropy.table.Table
+            Table of pointing values, expected columns
+            are ``time`` as ``Time`` column and "pedestal"
+            for the pedestal data
+        """
 
-        self.required_columns = {"time", par_name}
+        self.required_columns = {"time", "pedestal"}
 
         self._check_tables(input_table)
 
         input_table.sort("time")
         time = input_table["time"]
-        cal = input_table[par_name]
+        pedestal = input_table["pedestal"]
         self._interpolators[tel_id] = {}
-        self._interpolators[tel_id][par_name] = StepFunction(
-            time, cal, **self.interp_options
+        self._interpolators[tel_id]["pedestal"] = StepFunction(
+            time, pedestal, **self.interp_options
         )

src/ctapipe/io/tests/test_interpolator.py

@@ -5,7 +5,11 @@
 from astropy.table import Table
 from astropy.time import Time
 
-from ctapipe.io.interpolation import CalibrationInterpolator, PointingInterpolator
+from ctapipe.io.interpolation import (
+    GainInterpolator,
+    PedestalInterpolator,
+    PointingInterpolator,
+)
 
 t0 = Time("2022-01-01T00:00:00")
 
@@ -97,25 +101,37 @@ def test_bounds():
         },
     )
 
-    table_cal = Table(
+    table_pedestal = Table(
         {
             "time": np.arange(0.0, 10.1, 2.0),
             "pedestal": np.reshape(np.random.normal(4.0, 1.0, 1850 * 6), (6, 1850)),
         },
     )
 
+    table_gain = Table(
+        {
+            "time": np.arange(0.0, 10.1, 2.0),
+            "gain": np.reshape(np.random.normal(1.0, 1.0, 1850 * 6), (6, 1850)),
+        },
+    )
+
     interpolator_pointing = PointingInterpolator()
-    interpolator_cal = CalibrationInterpolator()
+    interpolator_pedestal = PedestalInterpolator()
+    interpolator_gain = GainInterpolator()
     interpolator_pointing.add_table(1, table_pointing)
-    interpolator_cal.add_table(1, table_cal, "pedestal")
+    interpolator_pedestal.add_table(1, table_pedestal)
+    interpolator_gain.add_table(1, table_gain)
 
     error_message = "below the interpolation range"
 
     with pytest.raises(ValueError, match=error_message):
         interpolator_pointing(tel_id=1, time=t0 - 0.1 * u.s)
 
     with pytest.raises(ValueError, match=error_message):
-        interpolator_cal(tel_id=1, time=-0.1)
+        interpolator_pedestal(tel_id=1, time=-0.1)
+
+    with pytest.raises(ValueError, match=error_message):
+        interpolator_gain(tel_id=1, time=-0.1)
 
     with pytest.raises(ValueError, match="above the interpolation range"):
         interpolator_pointing(tel_id=1, time=t0 + 10.2 * u.s)
@@ -124,24 +140,31 @@ def test_bounds():
     assert u.isclose(alt, 69 * u.deg)
     assert u.isclose(az, 1 * u.deg)
 
-    pedestal = interpolator_cal(tel_id=1, time=1.0)
-    assert all(pedestal == table_cal["pedestal"][0])
+    pedestal = interpolator_pedestal(tel_id=1, time=1.0)
+    assert all(pedestal == table_pedestal["pedestal"][0])
+    gain = interpolator_gain(tel_id=1, time=1.0)
+    assert all(gain == table_gain["gain"][0])
     with pytest.raises(KeyError):
         interpolator_pointing(tel_id=2, time=t0 + 1 * u.s)
     with pytest.raises(KeyError):
-        interpolator_cal(tel_id=2, time=1.0)
+        interpolator_pedestal(tel_id=2, time=1.0)
+    with pytest.raises(KeyError):
+        interpolator_gain(tel_id=2, time=1.0)
 
     interpolator_pointing = PointingInterpolator(bounds_error=False)
-    interpolator_cal = CalibrationInterpolator(bounds_error=False)
+    interpolator_pedestal = PedestalInterpolator(bounds_error=False)
+    interpolator_gain = GainInterpolator(bounds_error=False)
     interpolator_pointing.add_table(1, table_pointing)
-    interpolator_cal.add_table(1, table_cal, "pedestal")
+    interpolator_pedestal.add_table(1, table_pedestal)
+    interpolator_gain.add_table(1, table_gain)
 
     for dt in (-0.1, 10.1) * u.s:
         alt, az = interpolator_pointing(tel_id=1, time=t0 + dt)
         assert np.isnan(alt.value)
         assert np.isnan(az.value)
 
-    assert all(np.isnan(interpolator_cal(tel_id=1, time=-0.1)))
+    assert all(np.isnan(interpolator_pedestal(tel_id=1, time=-0.1)))
+    assert all(np.isnan(interpolator_gain(tel_id=1, time=-0.1)))
 
     interpolator_pointing = PointingInterpolator(bounds_error=False, extrapolate=True)
     interpolator_pointing.add_table(1, table_pointing)