Add a UVBeam.new method similar to the ones on UVData and UVCal

Deprecate the unused `spw_array` and `Nspws` attributes on UVBeam.

Deprecate the `UVBeam.freq_interp_kind` attribute in favor of a parameter on the interp method.

Deprecate upper case strings in UVBeam.feed_array

CHANGELOG.md

@@ -4,6 +4,14 @@ All notable changes to this project will be documented in this file.
 ## [Unreleased]
 
 ### Added
+- A new `freq_interp_kind` parameter to `UVBeam.interp`, `UVBeam._interp_az_za_rect_spline`
+and `UVBeam._interp_healpix_bilinear` to allow the frequency interpolation
+specification to be passed into the methods. Note this defaults to "cubic" rather
+than "linear" (the old default for the attribute of the same name on UVBeam objects)
+because several groups have found that a linear interpolation leads to nasty
+artifacts in visibility simulations for EoR applications.
+- A new `UVBeam.new()` method (based on new function `new_uvbeam`) that creates a new,
+self-consistent `UVBeam` object from scratch from a set of flexible input parameters.
 - Added a the `UVData.update_antenna_positions` method to enable making antenna
 position updates with corresponding updates the uvw-coordinates and visibility phases.
 - Added a switch to `UVData.write_ms` called `flip_conj`, which allows a user to write
@@ -32,6 +40,12 @@ tolerance value to be user-specified.
 Additionally, failing this check results in a warning (was an error).
 
 ### Deprecated
+- The `freq_interp_kind` attribute on UVBeams.
+- The `spw_array` and `Nspws` attributes on UVBeam objects. Also the
+`unset_spw_params`  and `set_spw_params` parameters to the `use_future_array_shapes`
+and `use_current_array_shapes` methods on UVBeam objects.
+- Upper case feed names (e.g. "N" or "E") in UVBeam.feed_array. This was never
+fully tested and didn't work properly.
 - Having `freq_range` defined on non-wide-band gain style UVCal objects.
 - Having `freq_array` and `channel_width` defined on wide-band UVCal objects.
 

pyuvdata/uvbeam/beamfits.py

@@ -253,9 +253,6 @@ def read_beamfits(
                             "UVBeam does not support having a spectral window axis "
                             "larger than one."
                         )
-                    if not use_future_array_shapes:
-                        self.Nspws = 1
-                        self.spw_array = np.array([0])
 
             if n_dimensions > ax_nums["basisvec"] - 1:
                 if (
@@ -268,12 +265,7 @@ def read_beamfits(
                         "NAXIS" + str(ax_nums["basisvec"]), None
                     )
 
-            if (
-                self.Nspws is None or self.Naxes_vec is None
-            ) and self.beam_type == "power":
-                if self.Nspws is None and not use_future_array_shapes:
-                    self.Nspws = 1
-                    self.spw_array = np.array([0])
+            if self.Naxes_vec is None and self.beam_type == "power":
                 if self.Naxes_vec is None:
                     self.Naxes_vec = 1
 
@@ -365,7 +357,6 @@ def read_beamfits(
             self.model_name = primary_header.pop("MODEL", None)
             self.model_version = primary_header.pop("MODELVER", None)
             self.x_orientation = primary_header.pop("XORIENT", None)
-            self.freq_interp_kind = primary_header.pop("FINTERP", None)
 
             self.history = str(primary_header.get("HISTORY", ""))
             if not uvutils._check_history_version(
@@ -663,12 +654,6 @@ def write_beamfits(
         if self.x_orientation is not None:
             primary_header["XORIENT"] = self.x_orientation
 
-        if self.freq_interp_kind is not None:
-            primary_header["FINTERP"] = (
-                self.freq_interp_kind,
-                "frequency " "interpolation kind (scipy interp1d)",
-            )
-
         if self.beam_type == "efield":
             primary_header["FEEDLIST"] = "[" + ", ".join(self.feed_array) + "]"
 

pyuvdata/uvbeam/cst_beam.py

@@ -200,9 +200,6 @@ def read_cst_beam(
         self.freq_array = np.zeros((1, self.Nfreqs))
         self.bandpass_array = np.zeros((1, self.Nfreqs))
 
-        if not use_future_array_shapes:
-            self.Nspws = 1
-            self.spw_array = np.array([0])
         self.pixel_coordinate_system = "az_za"
         self._set_cs_params()