Remove large objects from Piff results by default

python/lsst/meas/extensions/piff/piffPsfDeterminer.py

@@ -105,6 +105,10 @@ class PiffPsfDeterminerConfig(BasePsfDeterminerTask.ConfigClass):
         check=_validateGalsimInterpolant,
         default="Lanczos(11)",
     )
+    debugStarData = pexConfig.Field[bool](
+        doc="Include star images used for fitting in PSF model object.",
+        default=False
+    )
 
     def setDefaults(self):
         super().setDefaults()
@@ -342,7 +346,6 @@ def determinePsf(
 
         piffResult.fit(stars, wcs, pointing, logger=self.log)
         drawSize = 2*np.floor(0.5*stampSize/self.config.samplingSize) + 1
-        psf = PiffPsf(drawSize, drawSize, piffResult)
 
         used_image_pos = [s.image_pos for s in piffResult.stars]
         if flagKey:
@@ -359,7 +362,18 @@ def determinePsf(
             metadata["avgX"] = np.mean([p.x for p in piffResult.stars])
             metadata["avgY"] = np.mean([p.y for p in piffResult.stars])
 
-        return psf, None
+        if not self.config.debugStarData:
+            for star in piffResult.stars:
+                # Remove large data objects from the stars
+                del star.fit.params
+                del star.fit.params_var
+                del star.fit.A
+                del star.fit.b
+                del star.data.image
+                del star.data.weight
+                del star.data.orig_weight
+
+        return PiffPsf(drawSize, drawSize, piffResult), None
 
     # TODO: DM-36311: This method can be removed.
     @staticmethod

tests/test_psf.py

@@ -161,7 +161,7 @@ def setUp(self):
             cand = measAlg.makePsfCandidate(source, self.exposure)
             self.cellSet.insertCandidate(cand)
 
-    def setupDeterminer(self, stampSize=None):
+    def setupDeterminer(self, stampSize=None, debugStarData=False):
         """Setup the starSelector and psfDeterminer
 
         Parameters
@@ -192,6 +192,7 @@ def setupDeterminer(self, stampSize=None):
         psfDeterminerConfig.spatialOrder = 1
         if stampSize is not None:
             psfDeterminerConfig.stampSize = stampSize
+        psfDeterminerConfig.debugStarData = debugStarData
 
         self.psfDeterminer = PiffPsfDeterminerTask(psfDeterminerConfig)
 
@@ -218,15 +219,15 @@ def subtractStars(self, exposure, catalog, chi_lim=-1):
             self.assertGreater(chi_min, -chi_lim)
             self.assertLess(chi_max, chi_lim)
 
-    def checkPiffDeterminer(self, stampSize=None):
+    def checkPiffDeterminer(self, stampSize=None, debugStarData=False):
         """Configure PiffPsfDeterminerTask and run basic tests on it.
 
         Parameters
         ----------
         stampSize : `int`, optional
             Set ``config.stampSize`` to this, if not None.
         """
-        self.setupDeterminer(stampSize=stampSize)
+        self.setupDeterminer(stampSize=stampSize, debugStarData=debugStarData)
         metadata = dafBase.PropertyList()
 
         stars = self.starSelector.run(self.catalog, exposure=self.exposure)
@@ -251,6 +252,10 @@ def checkPiffDeterminer(self, stampSize=None):
                 np.mean([s.y for s in psf._piffResult.stars])
             )
         )
+        if self.psfDeterminer.config.debugStarData:
+            self.assertIn('image', psf._piffResult.stars[0].data.__dict__)
+        else:
+            self.assertNotIn('image', psf._piffResult.stars[0].data.__dict__)
 
         # Test how well we can subtract the PSF model
         self.subtractStars(self.exposure, self.catalog, chi_lim=6.1)
@@ -308,6 +313,10 @@ def testPiffDeterminer_kernelSize27(self):
         """Test Piff with a psf kernelSize of 27."""
         self.checkPiffDeterminer(27)
 
+    def testPiffDeterminer_debugStarData(self):
+        """Test Piff with debugStarData=True."""
+        self.checkPiffDeterminer(debugStarData=True)
+
     @lsst.utils.tests.methodParameters(samplingSize=[1.0, 0.9, 1.1])
     def test_validatePsfCandidates(self, samplingSize):
         """Test that `_validatePsfCandidates` raises for too-small candidates.