Merge pull request #323 from lsst/tickets/DM-44507

DM-44507: Investigate unexpectedly large transform passed to WarpedPsf in diffim
lsst · Jun 7, 2024 · 04c3c9f · 04c3c9f
2 parents 5d17e6b + 9ca000c
commit 04c3c9f
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Showing 4 changed files with 14 additions and 9 deletions.
diff --git a/python/lsst/ip/diffim/computeSpatiallySampledMetrics.py b/python/lsst/ip/diffim/computeSpatiallySampledMetrics.py
@@ -29,7 +29,7 @@
 
 from lsst.ip.diffim.utils import getPsfFwhm, angleMean, evaluateMaskFraction
 from lsst.meas.algorithms import SkyObjectsTask
-from lsst.pex.exceptions import InvalidParameterError
+from lsst.pex.exceptions import InvalidParameterError, RangeError
 from lsst.utils.timer import timeMethod
 
 import lsst.utils
@@ -235,7 +235,7 @@ def _evaluateLocalMetric(self, src, science, matchedTemplate, template, differen
         src.set('science_psfSize', getPsfFwhm(science.psf, position=pix))
         try:
             src.set('template_psfSize', getPsfFwhm(template.psf, position=pix))
-        except InvalidParameterError:
+        except (InvalidParameterError, RangeError):
             src.set('template_psfSize', np.nan)
 
         metricRegionSize = 100

diff --git a/python/lsst/ip/diffim/makeKernel.py b/python/lsst/ip/diffim/makeKernel.py
@@ -31,7 +31,7 @@
 import lsst.geom
 from lsst.meas.algorithms import SourceDetectionTask, SubtractBackgroundTask
 from lsst.meas.base import SingleFrameMeasurementTask
-from lsst.pex.exceptions import InvalidParameterError
+from lsst.pex.exceptions import InvalidParameterError, RangeError
 import lsst.pex.config
 import lsst.pipe.base
 
@@ -140,7 +140,7 @@ def run(self, template, science, kernelSources, preconvolved=False):
         try:
             templateFwhmPix = getPsfFwhm(template.psf)
             scienceFwhmPix = getPsfFwhm(science.psf)
-        except InvalidParameterError:
+        except (InvalidParameterError, RangeError):
             self.log.debug("Unable to evaluate PSF at the average position. "
                            "Evaluting PSF on a grid of points."
                            )
@@ -191,7 +191,7 @@ def selectKernelSources(self, template, science, candidateList=None, preconvolve
         try:
             templateFwhmPix = getPsfFwhm(template.psf)
             scienceFwhmPix = getPsfFwhm(science.psf)
-        except InvalidParameterError:
+        except (InvalidParameterError, RangeError):
             self.log.debug("Unable to evaluate PSF at the average position. "
                            "Evaluting PSF on a grid of points."
                            )

diff --git a/python/lsst/ip/diffim/subtractImages.py b/python/lsst/ip/diffim/subtractImages.py
@@ -389,10 +389,15 @@ def run(self, template, science, sources, finalizedPsfApCorrCatalog=None,
         # evaluate the PSF on a grid specified by fwhmExposure* fields.
         # To keep consistent definitions for PSF size on the template and
         # science images, we use the same method for both.
+        # In the try block below, we catch two exceptions:
+        # 1. InvalidParameterError, in case the point where we are evaluating
+        #    the PSF lands in a gap in the template.
+        # 2. RangeError, in case the template coverage is so poor that we end
+        #    up near a region with no data.
         try:
             templatePsfSize = getPsfFwhm(template.psf)
             sciencePsfSize = getPsfFwhm(science.psf)
-        except lsst.pex.exceptions.InvalidParameterError:
+        except (lsst.pex.exceptions.InvalidParameterError, lsst.pex.exceptions.RangeError):
             self.log.info("Unable to evaluate PSF at the average position. "
                           "Evaluting PSF on a grid of points."
                           )
@@ -1218,7 +1223,7 @@ def _shapeTest(exp1, exp2, fwhmExposureBuffer, fwhmExposureGrid):
     try:
         shape1 = getPsfFwhm(exp1.psf, average=False)
         shape2 = getPsfFwhm(exp2.psf, average=False)
-    except lsst.pex.exceptions.InvalidParameterError:
+    except (lsst.pex.exceptions.InvalidParameterError, lsst.pex.exceptions.RangeError):
         shape1 = evaluateMeanPsfFwhm(exp1,
                                      fwhmExposureBuffer=fwhmExposureBuffer,
                                      fwhmExposureGrid=fwhmExposureGrid

diff --git a/python/lsst/ip/diffim/utils.py b/python/lsst/ip/diffim/utils.py
@@ -37,7 +37,7 @@
 import lsst.meas.algorithms as measAlg
 import lsst.meas.base as measBase
 from lsst.meas.algorithms.testUtils import plantSources
-from lsst.pex.exceptions import InvalidParameterError
+from lsst.pex.exceptions import InvalidParameterError, RangeError
 from lsst.utils.logging import getLogger
 from .dipoleFitTask import DipoleFitAlgorithm
 from . import diffimLib
@@ -937,7 +937,7 @@ def evaluateMeanPsfFwhm(exposure: afwImage.Exposure,
         pos = geom.Point2D(x, y)
         try:
             fwhm = getPsfFwhm(psf, average=True, position=pos)
-        except InvalidParameterError:
+        except (InvalidParameterError, RangeError):
             _LOG.debug("Unable to compute PSF FWHM at position (%f, %f).", x, y)
             continue