Preserve output table units with new version of astropy

.gitignore

@@ -36,6 +36,7 @@ docs/_build
 dist
 build
 eggs
+.eggs
 parts
 bin
 var

CHANGES.rst

@@ -1,6 +1,7 @@
 0.9 (unreleased)
 ----------------
 
+- Fix Simulator output table units with astropy 1.3.2 (#62).
 - Add support for simulating calibration exposures (#54).
 - Add wavelength min/max options to Simulator.plot().
 - Better support for alternate simulation wavelength grids (PR #60).

setup.cfg

@@ -12,7 +12,7 @@ all_files = 1
 upload-dir = docs/_build/html
 show-response = 1
 
-[pytest]
+[tool:pytest]
 minversion = 2.2
 norecursedirs = build docs/_build
 doctest_plus = enabled

specsim/simulator.py

@@ -477,32 +477,32 @@ def simulate(self, sky_positions=None, focal_positions=None,
                 camera.read_noise_per_bin[:, np.newaxis].to(u.electron).value)
 
             # Calculate the corresponding downsampled output quantities.
-            output['num_source_electrons'] = (
+            output['num_source_electrons'][:] = (
                 camera.downsample(num_source_electrons.T)).T
-            output['num_sky_electrons'] = (
+            output['num_sky_electrons'][:] = (
                 camera.downsample(num_sky_electrons.T)).T
-            output['num_dark_electrons'] = (
+            output['num_dark_electrons'][:] = (
                 camera.downsample(num_dark_electrons.T)).T
-            output['read_noise_electrons'] = np.sqrt(
+            output['read_noise_electrons'][:] = np.sqrt(
                 camera.downsample(read_noise_electrons.T ** 2)).T
-            output['variance_electrons'] = (
+            output['variance_electrons'][:] = (
                 output['num_source_electrons'] +
                 output['num_sky_electrons'] +
                 output['num_dark_electrons'] +
                 output['read_noise_electrons'] ** 2)
 
             # Calculate the effective calibration from detected electrons to
             # source flux above the atmosphere, downsampled to output pixels.
-            output['flux_calibration'] = 1.0 / camera.downsample(
+            output['flux_calibration'][:] = 1.0 / camera.downsample(
                 camera.apply_resolution(
                     source_flux_to_photons.T * camera.throughput)).T
 
             # Calculate the calibrated flux in this camera.
-            output['observed_flux'] = (
+            output['observed_flux'][:] = (
                 output['flux_calibration'] * output['num_source_electrons'])
 
             # Calculate the corresponding flux inverse variance.
-            output['flux_inverse_variance'] = (
+            output['flux_inverse_variance'][:] = (
                 output['flux_calibration'] ** -2 *
                 output['variance_electrons'] ** -1)
 

specsim/tests/test_simulator.py

@@ -110,6 +110,22 @@ def test_fiber_positioning():
     assert np.allclose(sim.focal_y.to(u.mm).value, 0.)
 
 
+def test_output_table_units():
+    """Test that units are preserved after calling simulate().
+
+    This test was added in response to issue #62
+    """
+    sim = specsim.simulator.Simulator('test', num_fibers=1)
+    units_before = {}
+    for table in (sim.simulated, sim.camera_output[0]):
+        for name in table.colnames:
+            units_before[name] = table[name].unit
+    sim.simulate()
+    for table in (sim.simulated, sim.camera_output[0]):
+        for name in table.colnames:
+            assert units_before[name] == table[name].unit
+
+
 def test_plot():
     s = Simulator('test')
     s.simulate()