Merge pull request #263 from nkhadka21/galsim_fix

galasim import issue fix

slsim/lens_pop.py

@@ -71,19 +71,23 @@ def __init__(
         if self.los_config is None:
             self.los_config = LOSConfig()
 
-    def select_lens_at_random(self, **kwargs_lens_cut):
+    def select_lens_at_random(self, test_area=None, **kwargs_lens_cut):
         """Draw a random lens within the cuts of the lens and source, with possible
         additional cut in the lensing configuration.
-
         # TODO: make sure mass function is preserved, # as well as option to draw all
         lenses within the cuts within the area
-
+        :param test_area: solid angle around one lensing galaxies to be investigated on
+            (in arc-seconds^2). If None, computed using deflector's velocity dispersion.
         :return: Lens() instance with parameters of the deflector and lens and source
             light
         """
         while True:
             source = self._sources.draw_source()
             lens = self._lens_galaxies.draw_deflector()
+            if test_area is None:
+                test_area = draw_test_area(deflector=lens)
+            else:
+                test_area = test_area
             gg_lens = Lens(
                 deflector_dict=lens,
                 source_dict=source,
@@ -94,6 +98,7 @@ def select_lens_at_random(self, **kwargs_lens_cut):
                 sn_absolute_mag_band=self.sn_absolute_mag_band,
                 sn_absolute_zpsys=self.sn_absolute_zpsys,
                 cosmo=self.cosmo,
+                test_area=test_area,
                 source_type=self._sources.source_type,
                 light_profile=self._sources.light_profile,
                 lightcurve_time=self.lightcurve_time,

slsim/roman_image_simulation.py

@@ -6,15 +6,17 @@
 import os.path
 import pickle
 from webbpsf.roman import WFI
+import warnings
 
 try:
     import galsim
     from galsim import Image, InterpolatedImage, roman
 except ModuleNotFoundError:
-    raise ModuleNotFoundError(
-        "Please install the galsim module in order to use simulate_roman_image.\n"
+    warning_msg = (
+"If you want to simulate images with Roman filters, please install the galsim module.\n"
         "Note that this module is not supported on Windows"
-    )
+            )
+    warnings.warn(warning_msg, category=UserWarning, stacklevel=2)
 
 # NOTE: Adding sky background requires webbpsf-data, which can be found at
 #       https://webbpsf.readthedocs.io/en/latest/installation.html. Then, the

tests/test_lens_pop.py

@@ -183,7 +183,9 @@ def test_cluster_lens_pop_instance():
     )
 
     kwargs_lens_cut = {}
-    pes_lens_class = cluster_lens_pop.select_lens_at_random(**kwargs_lens_cut)
+    pes_lens_class = cluster_lens_pop.select_lens_at_random(
+        test_area=4 * np.pi, **kwargs_lens_cut
+    )
     assert pes_lens_class.deflector.deflector_type == "NFW_CLUSTER"
     kwargs_model, kwargs_params = pes_lens_class.lenstronomy_kwargs(band="g")
     assert len(kwargs_model["lens_model_list"]) >= 3  # halo, 1>= subhalo, LoS