Merge pull request #230 from esheldon/bdf-guesser

add guesser for BDF with psf flux

Author: esheldon

CHANGES.md

@@ -1,3 +1,19 @@
+## v2.2.1
+
+### New Features
+
+   - Added new guesser BDFPSFFluxGuesser, makes a flux guess
+     based on the PSF flux
+
+### Performance
+   - Added O(N) phase shift computation for pre-psf moments
+
+### Misc
+
+   - ignore NumbaExperimentalFeatureWarning being spewed by
+     numba.  We can ignore these, as the features are of order
+     ten years old from the time of writing
+
 ## v2.2.0
 
 ### new features

ngmix/__init__.py

@@ -1,5 +1,10 @@
 # flake8: noqa
 
+from numba.core.errors import NumbaExperimentalFeatureWarning
+import warnings
+
+warnings.simplefilter('ignore', category=NumbaExperimentalFeatureWarning)
+
 from ._version import __version__
 
 from . import util

ngmix/_version.py

@@ -1 +1 @@
-__version__ = '2.2.0'  # noqa
+__version__ = '2.2.1'  # noqa

ngmix/guessers.py

@@ -322,6 +322,60 @@ def __call__(self, nrand=1, obs=None):
         return guess
 
 
+class BDFPSFFluxGuesser(TPSFFluxGuesser):
+    """
+    Make BDF guesses from the input T, the psf flux and the prior
+
+    parameters
+    ----------
+    T: float
+        Center for T guesses
+    prior:
+        cen, g drawn from this prior
+    """
+
+    def __init__(self, T, prior):
+        self.T = T
+        self.prior = prior
+        self._id_last = None
+        self._psf_fluxes = None
+        self.rng = self.prior.cen_prior.rng
+
+    def __call__(self, obs, nrand=1):
+        """
+        center, shape are just distributed around zero
+
+        obs: Observation
+            The observation(s) used for psf fluxes
+        nrand: int, optional
+            Number of samples to draw.  Default 1
+        """
+        rng = self.prior.cen_prior.rng
+
+        fluxes = self._get_psf_fluxes(obs=obs)
+
+        guess = self.prior.sample(nrand)
+
+        nband = fluxes.size
+
+        r = rng.uniform(low=-0.1, high=0.1, size=nrand)
+        guess[:, 4] = self.T * (1.0 + r)
+
+        # fracdev prior
+        guess[:, 5] = rng.uniform(low=0.4, high=0.6, size=nrand)
+
+        for band in range(nband):
+            r = rng.uniform(low=-0.1, high=0.1, size=nrand)
+            guess[:, 6 + band] = fluxes[band] * (1.0 + r)
+
+        _fix_guess(guess, self.prior)
+
+        if nrand == 1:
+            guess = guess[0, :]
+
+        return guess
+
+
 class BDFGuesser(object):
     """
     Make BDF guesses from the input T, flux and prior
@@ -368,8 +422,7 @@ def __call__(self, nrand=1, obs=None):
             r = rng.uniform(low=-0.1, high=0.1, size=nrand)
             guess[:, 6 + band] = fluxes[band] * (1.0 + r)
 
-        if self.prior is not None:
-            _fix_guess(guess, self.prior)
+        _fix_guess(guess, self.prior)
 
         if nrand == 1:
             guess = guess[0, :]

ngmix/tests/test_guessers.py

@@ -94,7 +94,7 @@ def test_noprior_guessers_smoke(guesser_type, nband, with_prior):
 
 @pytest.mark.parametrize(
     'guesser_type',
-    ['TFluxAndPrior', 'TPSFFluxAndPrior', 'BD', 'BDF', 'Prior'],
+    ['TFluxAndPrior', 'TPSFFluxAndPrior', 'BD', 'BDF', 'BDFPSFlux', 'Prior'],
 )
 @pytest.mark.parametrize('nband', [None, 1, 2])
 def test_prior_guessers_smoke(guesser_type, nband):
@@ -113,7 +113,7 @@ def test_prior_guessers_smoke(guesser_type, nband):
 
         # this always gets coverage
         assert guesser_type in [
-            'TFluxAndPrior', 'TPSFFluxAndPrior', 'BD', 'BDF', 'Prior',
+            'TFluxAndPrior', 'TPSFFluxAndPrior', 'BD', 'BDF', 'BDFPSFlux', 'Prior',
         ]
 
         T_center = 0.001
@@ -150,17 +150,22 @@ def test_prior_guessers_smoke(guesser_type, nband):
                 T=T_center, flux=flux_center, prior=prior,
             )
             npars = 7 + nband_use
-        elif guesser_type == 'BDF':
+        elif guesser_type in ('BDF', 'BDFPSFlux'):
             prior = ngmix.joint_prior.PriorBDFSep(
                 cen_prior=ngmix.priors.CenPrior(0.0, 0.0, 0.1, 0.1, rng=rng),
                 g_prior=ngmix.priors.GPriorBA(0.3, rng=rng),
                 fracdev_prior=ngmix.priors.Normal(0.5, 0.1, rng=rng),
                 T_prior=ngmix.priors.FlatPrior(-1.0, 1.e5, rng=rng),
                 F_prior=[ngmix.priors.FlatPrior(-1.0, 1.e5, rng=rng)]*nband_use,
             )
-            guesser = guessers.BDFGuesser(
-                T=T_center, flux=flux_center, prior=prior,
-            )
+            if guesser_type == 'BDF':
+                guesser = guessers.BDFGuesser(
+                    T=T_center, flux=flux_center, prior=prior,
+                )
+            else:
+                guesser = guessers.BDFPSFFluxGuesser(
+                    T=T_center, prior=prior,
+                )
             npars = 6 + nband_use
 
         guess = guesser(obs=data['obs'])