Coverage for python/lsst/meas/algorithms/psfDeterminer.py: 58%

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1# This file is part of meas_algorithms. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (https://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This program is free software: you can redistribute it and/or modify 

10# it under the terms of the GNU General Public License as published by 

11# the Free Software Foundation, either version 3 of the License, or 

12# (at your option) any later version. 

13# 

14# This program is distributed in the hope that it will be useful, 

15# but WITHOUT ANY WARRANTY; without even the implied warranty of 

16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

17# GNU General Public License for more details. 

18# 

19# You should have received a copy of the GNU General Public License 

20# along with this program. If not, see <https://www.gnu.org/licenses/>. 

21 

22__all__ = ["BasePsfDeterminerConfig", "BasePsfDeterminerTask", "psfDeterminerRegistry"] 

23 

24import abc 

25import numpy as np 

26 

27import lsst.pipe.base as pipeBase 

28import lsst.pex.config as pexConfig 

29 

30 

31class BasePsfDeterminerConfig(pexConfig.Config): 

32 """Configuration that is likely to be shared by all PSF determiners 

33 

34 This is fairly sparse; more fields can be moved here once it is clear they are universal. 

35 """ 

36 stampSize = pexConfig.Field[int]( 36 ↛ exitline 36 didn't jump to the function exit

37 doc="Size of the postage stamp (in native pixels) to render the PSF model. Should be odd.", 

38 default=None, 

39 optional=True, 

40 check=lambda x: (x > 0) & (x % 2 == 1), 

41 ) 

42 maxCandidates = pexConfig.Field[int]( 

43 doc="Maximum number of candidates to consider. Will down-sample if given more.", 

44 default=300, 

45 ) 

46 downsampleRandomSeed = pexConfig.Field[int]( 

47 doc="Random seed to use to downsample candidates.", 

48 default=98765, 

49 ) 

50 

51 

52class BasePsfDeterminerTask(pipeBase.Task, metaclass=abc.ABCMeta): 

53 """Base class for PSF determiners 

54 

55 Register all PSF determiners with the psfDeterminerRegistry using: 

56 psfDeterminerRegistry.register(name, class) 

57 

58 Parameters 

59 ---------- 

60 config : `lsst.pexConfig.Config` 

61 Input for configuring the algorithm 

62 schema : `lsst.afw.table.Schema` 

63 Schema used for sources; passing a schema allows the 

64 determiner to reserve a flag field to mark stars used in 

65 PSF measurement, but some PSF determiners ignore this argument. 

66 """ 

67 

68 usesMatches = False # Does the PSF determiner use the "matches" argument in the "run method? Few do. 

69 ConfigClass = BasePsfDeterminerConfig 

70 _DefaultName = "psfDeterminer" 

71 

72 def __init__(self, config, schema=None, **kwds): 

73 pipeBase.Task.__init__(self, config=config, **kwds) 

74 

75 def downsampleCandidates(self, inputCandidateList): 

76 """Down-sample candidates from the input candidate list. 

77 

78 Parameters 

79 ---------- 

80 inputCandidateList : `list` [`lsst.meas.algorithms.PsfCandidate`] 

81 Input candidate list. 

82 

83 Returns 

84 ------- 

85 outputCandidateList : `list` [`lsst.meas.algorithms.PsfCandidate`] 

86 Down-selected candidate list. 

87 """ 

88 if len(inputCandidateList) <= self.config.maxCandidates: 

89 return inputCandidateList 

90 

91 rng = np.random.RandomState(seed=self.config.downsampleRandomSeed) 

92 

93 self.log.info( 

94 "Down-sampling from %d to %d psf candidates.", 

95 len(inputCandidateList), 

96 self.config.maxCandidates, 

97 ) 

98 

99 selection = rng.choice(len(inputCandidateList), size=self.config.maxCandidates, replace=False) 

100 selection = np.sort(selection) 

101 

102 outputCandidateList = [inputCandidateList[index] for index in selection] 

103 

104 return outputCandidateList 

105 

106 @abc.abstractmethod 

107 def determinePsf(self, exposure, psfCandidateList, metadata=None, flagKey=None): 

108 """Determine a PSF model. 

109 

110 Parameters 

111 ---------- 

112 exposure : `lsst.afw.Exposure` 

113 Exposure containing the psf candidates. 

114 psdCandidateList : `list` [`lsst.meas.algorithms.PsfCandidate`] 

115 A sequence of PSF candidates; typically obtained by 

116 detecting sources and then running them through a star 

117 selector. 

118 metadata : `str`, optional 

119 A place to save interesting items. 

120 flagKey: `lsst.afw.table.Key`, optional 

121 Schema key used to mark sources actually used in PSF determination. 

122 

123 Returns 

124 ------- 

125 psf : `lsst.afw.detection.Psf` 

126 The fit PSF. 

127 cellSet : `lsst.afw.math.SpatialCellSet` 

128 The spatial cell set used to determine the PSF 

129 """ 

130 raise NotImplementedError("BasePsfDeterminerTask is abstract, subclasses must override this method") 

131 

132 

133psfDeterminerRegistry = pexConfig.makeRegistry( 

134 doc="A registry of PSF determiners (subclasses of BasePsfDeterminerTask)", 

135)