Merge pull request #83 from lsst/tickets/DM-48123

DM-48123: Make seed generation possible with long exposure/visit IDs
lsst · Jan 6, 2025 · 982c578 · 982c578
2 parents ede91d6 + 4a908b2
commit 982c578
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diff --git a/python/lsst/drp/tasks/make_direct_warp.py b/python/lsst/drp/tasks/make_direct_warp.py
@@ -503,7 +503,10 @@ def run(self, inputs: Mapping[int, WarpDetectorInputs], sky_info, visit_summary)
             input_exposure = detector_inputs.exposure
             # Generate noise image(s) in-situ.
             seed = self.get_seed_from_data_id(detector_inputs.data_id)
-            rng = np.random.RandomState(seed + self.config.seedOffset)
+            # Limit to last 32 bits to avoid overflow in numpy.
+            np_seed = (seed + self.config.seedOffset) & 0xFFFFFFFF
+            self.log.debug("Setting numpy random seed to %d for noise realization", np_seed)
+            rng = np.random.RandomState(np_seed)
 
             # Generate noise images in-situ.
             noise_calexps = self.make_noise_exposures(input_exposure, rng)

diff --git a/tests/test_make_direct_warp.py b/tests/test_make_direct_warp.py
@@ -365,6 +365,38 @@ def test_background_errors(self):
         with self.assertRaises(RuntimeError, msg="No background to revert"):
             makeWarp.run(warp_detector_inputs, sky_info=self.skyInfo, visit_summary=None)
 
+    def test_long_data_ids(self):
+        """Test MakeDirectWarpTask fails gracefully with no good pixels.
+
+        It should return an empty exposure, with no PSF.
+        """
+        warp_detector_inputs = {
+            self.dataRef.dataId.detector.id: WarpDetectorInputs(
+                exposure_or_handle=self.dataRef, data_id=self.dataRef.dataId
+            )
+        }
+
+        self.config.border = 0  # Repeated calls will expand it otherwise.
+        makeWarp_original = MakeDirectWarpTask(config=self.config)
+        makeWarp_short = MakeDirectWarpTask(config=self.config)
+        makeWarp_short.get_seed_from_data_id = (
+            lambda data_id: 2**32 - 1 + makeWarp_original.get_seed_from_data_id(data_id)
+        )
+        makeWarp_long = MakeDirectWarpTask(config=self.config)
+        makeWarp_long.get_seed_from_data_id = lambda data_id: 2**32 + makeWarp_original.get_seed_from_data_id(
+            data_id
+        )
+
+        result_long = makeWarp_long.run(warp_detector_inputs, sky_info=self.skyInfo, visit_summary=None)
+        result_short = makeWarp_short.run(warp_detector_inputs, sky_info=self.skyInfo, visit_summary=None)
+        result_original = makeWarp_original.run(
+            warp_detector_inputs, sky_info=self.skyInfo, visit_summary=None
+        )
+
+        self.assertMaskedImagesAlmostEqual(result_long.noise_warp0, result_original.noise_warp0, atol=6e-8)
+        with self.assertRaises(AssertionError):
+            self.assertMaskedImagesEqual(result_short.noise_warp0, result_original.noise_warp0)
+
 
 class MakeWarpNoGoodPixelsTestCase(MakeWarpTestCase):
     def setUp(self):
@@ -393,6 +425,9 @@ def test_makeWarp(self):
     def test_compare_warps(self):
         """This test is not applicable when there are no good pixels."""
 
+    def test_long_data_ids(self):
+        """This test is not applicable when there are no good pixels."""
+
 
 def setup_module(module):
     lsst.utils.tests.init()