Merge pull request #156 from djhoese/bugfix-dtype-promotion2

Fix dtype preservation in astronomy functions

.github/workflows/ci.yaml

@@ -13,10 +13,10 @@ jobs:
  fail-fast: true
  matrix:
  os: ["windows-latest", "ubuntu-latest", "macos-latest"]
- python-version: ["3.9", "3.10", "3.11"]
+ python-version: ["3.9", "3.11", "3.12"]
  experimental: [false]
  include:
- - python-version: "3.11"
+ - python-version: "3.12"
  os: "ubuntu-latest"
  experimental: true
 

continuous_integration/environment.yaml

@@ -19,7 +19,6 @@ dependencies:
  - coverage
  - codecov
  - behave
- - mock
  - zarr
  - geoviews
  - pytest

pyorbital/astronomy.py

@@ -1,28 +1,42 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-
+#
 # Copyright (c) 2011, 2013
-
+#
 # Author(s):
-
+#
 # Martin Raspaud <[email protected]>
-
+#
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
-
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
-
+#
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
+"""Angle and time-based astronomy functions.
 
-"""Astronomy module.
 Parts taken from http://www.geoastro.de/elevaz/basics/index.htm
+
+Note on argument types
+----------------------
+
+Many of these functions accept Python datetime objects,
+numpy datetime64 objects, or anything that can be turned
+into a numpy array of datetime64 objects. These objects are inherently
+64-bit so if other arguments (ex. longitude and latitude arrays) are
+32-bit floats internal operations will be automatically promoted to
+64-bit floating point numbers. Where possible these are then converted
+back to 32-bit before being returned. In general scalar inputs will also
+produce scalar outputs.
+
 """
+import datetime
 
 import numpy as np
 
@@ -42,12 +56,14 @@ def jdays2000(utc_time):
 def jdays(utc_time):
  """Get the julian day of *utc_time*.
  """
- return jdays2000(utc_time) + 2451545
+ return jdays2000(utc_time) + 2451545.0
 
 
 def _days(dt):
  """Get the days (floating point) from *d_t*.
  """
+ if hasattr(dt, "shape"):
+ dt = np.asanyarray(dt, dtype=np.timedelta64)
  return dt / np.timedelta64(1, 'D')
 
 
@@ -117,6 +133,7 @@ def _local_hour_angle(utc_time, longitude, right_ascension):
 
 def get_alt_az(utc_time, lon, lat):
  """Return sun altitude and azimuth from *utc_time*, *lon*, and *lat*.
+
  lon,lat in degrees
  The returned angles are given in radians.
  """
@@ -125,10 +142,13 @@ def get_alt_az(utc_time, lon, lat):
 
  ra_, dec = sun_ra_dec(utc_time)
  h__ = _local_hour_angle(utc_time, lon, ra_)
- return (np.arcsin(np.sin(lat) * np.sin(dec) +
- np.cos(lat) * np.cos(dec) * np.cos(h__)),
- np.arctan2(-np.sin(h__), (np.cos(lat) * np.tan(dec) -
- np.sin(lat) * np.cos(h__))))
+ alt_az = (np.arcsin(np.sin(lat) * np.sin(dec) +
+ np.cos(lat) * np.cos(dec) * np.cos(h__)),
+ np.arctan2(-np.sin(h__), (np.cos(lat) * np.tan(dec) -
+ np.sin(lat) * np.cos(h__))))
+ if not isinstance(lon, float):
+ alt_az = (alt_az[0].astype(lon.dtype), alt_az[1].astype(lon.dtype))
+ return alt_az
 
 
 def cos_zen(utc_time, lon, lat):
@@ -141,21 +161,26 @@ def cos_zen(utc_time, lon, lat):
 
  r_a, dec = sun_ra_dec(utc_time)
  h__ = _local_hour_angle(utc_time, lon, r_a)
- return (np.sin(lat) * np.sin(dec) + np.cos(lat) * np.cos(dec) * np.cos(h__))
+ csza = (np.sin(lat) * np.sin(dec) + np.cos(lat) * np.cos(dec) * np.cos(h__))
+ if not isinstance(lon, float):
+ csza = csza.astype(lon.dtype)
+ return csza
 
 
 def sun_zenith_angle(utc_time, lon, lat):
  """Sun-zenith angle for *lon*, *lat* at *utc_time*.
  lon,lat in degrees.
  The angle returned is given in degrees
  """
- return np.rad2deg(np.arccos(cos_zen(utc_time, lon, lat)))
+ sza = np.rad2deg(np.arccos(cos_zen(utc_time, lon, lat)))
+ if not isinstance(lon, float):
+ sza = sza.astype(lon.dtype)
+ return sza
 
 
 def sun_earth_distance_correction(utc_time):
  """Calculate the sun earth distance correction, relative to 1 AU.
  """
-
  # Computation according to
  # https://web.archive.org/web/20150117190838/http://curious.astro.cornell.edu/question.php?number=582
  # with
@@ -175,11 +200,10 @@ def sun_earth_distance_correction(utc_time):
  # "=" 1 - 0.0167 * np.cos(theta)
 
  corr = 1 - 0.0167 * np.cos(2 * np.pi * (jdays2000(utc_time) - 3) / 365.25636)
-
  return corr
 
 
-def observer_position(time, lon, lat, alt):
+def observer_position(utc_time, lon, lat, alt):
  """Calculate observer ECI position.
 
  http://celestrak.com/columns/v02n03/
@@ -188,7 +212,7 @@ def observer_position(time, lon, lat, alt):
  lon = np.deg2rad(lon)
  lat = np.deg2rad(lat)
 
- theta = (gmst(time) + lon) % (2 * np.pi)
+ theta = (gmst(utc_time) + lon) % (2 * np.pi)
  c = 1 / np.sqrt(1 + F * (F - 2) * np.sin(lat)**2)
  sq = c * (1 - F)**2
 
@@ -199,6 +223,32 @@ def observer_position(time, lon, lat, alt):
 
  vx = -MFACTOR * y # kilometers/second
  vy = MFACTOR * x
- vz = 0
-
+ vz = _float_to_sibling_result(0.0, vx)
+
+ if not isinstance(lon, float):
+ x = x.astype(lon.dtype, copy=False)
+ y = y.astype(lon.dtype, copy=False)
+ z = z.astype(lon.dtype, copy=False)
+ vx = vx.astype(lon.dtype, copy=False)
+ vy = vy.astype(lon.dtype, copy=False)
+ vz = vz.astype(lon.dtype, copy=False) # type: ignore[union-attr]
  return (x, y, z), (vx, vy, vz)
+
+
+def _float_to_sibling_result(result_to_convert, template_result):
+ """Convert a scalar to the same type as another return type.
+
+ This is mostly used to make a static value consistent with the types of
+ other returned values.
+
+ """
+ if isinstance(template_result, float):
+ return result_to_convert
+ # get any array like object that might be wrapped by our template (ex. xarray DataArray)
+ array_like = template_result if hasattr(template_result, "__array_function__") else template_result.data
+ array_convert = np.asarray(result_to_convert, like=array_like)
+ if not hasattr(template_result, "__array_function__"):
+ # the template result has some wrapper class (likely xarray DataArray)
+ # recreate the wrapper object
+ array_convert = template_result.__class__(array_convert)
+ return array_convert

pyorbital/tests/__init__.py

@@ -20,25 +20,3 @@
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 """The tests package."""
-
-from pyorbital.tests import (test_aiaa, test_tlefile, test_orbital,
- test_astronomy, test_geoloc)
-import unittest
-
-
-def suite():
- """The global test suite."""
- mysuite = unittest.TestSuite()
- # Test the documentation strings
- # mysuite.addTests(doctest.DocTestSuite(image))
- # Use the unittests also
- mysuite.addTests(test_aiaa.suite())
- mysuite.addTests(test_tlefile.suite())
- mysuite.addTests(test_orbital.suite())
- mysuite.addTests(test_astronomy.suite())
- mysuite.addTests(test_geoloc.suite())
- return mysuite
-
-
-if __name__ == '__main__':
- unittest.TextTestRunner(verbosity=2).run(suite())

pyorbital/tests/test_astronomy.py

@@ -20,39 +20,97 @@
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
-import unittest
-
 from datetime import datetime
+
+import dask.array as da
+import numpy as np
+import numpy.typing as npt
+import pytest
+
 import pyorbital.astronomy as astr
 
+try:
+ from xarray import DataArray
+except ImportError:
+ DataArray = None
+
+
+def _create_dask_array(input_list: list, dtype: npt.DTypeLike) -> da.Array:
+ np_arr = np.array(input_list, dtype=dtype)
+ return da.from_array(np_arr)
+
 
-class TestAstronomy(unittest.TestCase):
+def _create_xarray_numpy(input_list: list, dtype: npt.DTypeLike) -> DataArray:
+ np_arr = np.array(input_list, dtype=dtype)
+ return DataArray(np_arr)
 
- def setUp(self):
- pass
 
- def test_jdays(self):
+def _create_xarray_dask(input_list: list, dtype: npt.DTypeLike) -> DataArray:
+ dask_arr = _create_dask_array(input_list, dtype)
+ return DataArray(dask_arr)
+
+
+class TestAstronomy:
+
+ @pytest.mark.parametrize(
+ ("dt", "exp_jdays", "exp_j2000"),
+ [
+ (datetime(2000, 1, 1, 12, 0), 2451545.0, 0),
+ (datetime(2009, 10, 8, 14, 30), 2455113.1041666665, 3568.1041666666665),
+ ]
+ )
+ def test_jdays(self, dt, exp_jdays, exp_j2000):
  """Test julian day functions."""
- t = datetime(2000, 1, 1, 12, 0)
- self.assertEqual(astr.jdays(t), 2451545.0)
- self.assertEqual(astr.jdays2000(t), 0)
- t = datetime(2009, 10, 8, 14, 30)
- self.assertEqual(astr.jdays(t), 2455113.1041666665)
- self.assertEqual(astr.jdays2000(t), 3568.1041666666665)
-
- def test_sunangles(self):
+ assert astr.jdays(dt) == exp_jdays
+ assert astr.jdays2000(dt) == exp_j2000
+
+ @pytest.mark.parametrize(
+ ("lon", "lat", "exp_theta"),
+ [
+ # Norrkoping
+ (16.1833, 58.6167, 60.371433482557833),
+ (0.0, 0.0, 1.8751916863323426),
+ ]
+ )
+ @pytest.mark.parametrize(
+ ("dtype", "array_construct"),
+ [
+ (None, None),
+ (np.float32, np.array),
+ (np.float64, np.array),
+ (np.float32, _create_dask_array),
+ (np.float64, _create_dask_array),
+ (np.float32, _create_xarray_numpy),
+ (np.float64, _create_xarray_numpy),
+ (np.float32, _create_xarray_dask),
+ (np.float64, _create_xarray_dask),
+ ]
+ )
+ def test_sunangles(self, lon, lat, exp_theta, dtype, array_construct):
  """Test the sun-angle calculations."""
- lat, lon = 58.6167, 16.1833 # Norrkoping
+ if array_construct is None and dtype is not None:
+ pytest.skip(reason="Xarray dependency unavailable")
+
  time_slot = datetime(2011, 9, 23, 12, 0)
+ abs_tolerance = 1e-8
+ if dtype is not None:
+ lon = array_construct([lon], dtype=dtype)
+ lat = array_construct([lat], dtype=dtype)
+ if np.dtype(dtype).itemsize < 8:
+ abs_tolerance = 1e-4
 
  sun_theta = astr.sun_zenith_angle(time_slot, lon, lat)
- self.assertAlmostEqual(sun_theta, 60.371433482557833, places=8)
- sun_theta = astr.sun_zenith_angle(time_slot, 0., 0.)
- self.assertAlmostEqual(sun_theta, 1.8751916863323426, places=8)
+ if dtype is None:
+ assert sun_theta == pytest.approx(exp_theta, abs=abs_tolerance)
+ assert isinstance(sun_theta, float)
+ else:
+ assert sun_theta.dtype == dtype
+ np.testing.assert_allclose(sun_theta, exp_theta, atol=abs_tolerance)
+ assert isinstance(sun_theta, type(lon))
 
  def test_sun_earth_distance_correction(self):
  """Test the sun-earth distance correction."""
  utc_time = datetime(2022, 6, 15, 12, 0, 0)
  corr = astr.sun_earth_distance_correction(utc_time)
  corr_exp = 1.0156952156742332
- self.assertAlmostEqual(corr, corr_exp, places=8)
+ assert corr == pytest.approx(corr_exp, abs=1e-8)

pyorbital/tests/test_orbital.py

@@ -24,10 +24,7 @@
 """
 
 import unittest
-try:
- from unittest import mock
-except ImportError:
- import mock
+from unittest import mock
 from datetime import datetime, timedelta
 
 import numpy as np