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1# This file is part of obs_base. 

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"""Classes to allow obs packages to define the filters used by an Instrument 

23and for use by `lsst.afw.image.Filter`, gen2 dataIds, and gen3 Dimensions. 

24""" 

25 

26__all__ = ("FilterDefinition", "FilterDefinitionCollection") 

27 

28import dataclasses 

29import collections.abc 

30 

31import numpy as np 

32 

33import lsst.afw.image.utils 

34 

35 

36class FilterDefinitionCollection(collections.abc.Sequence): 

37 """An order-preserving collection of multiple `FilterDefinition`. 

38 

39 Parameters 

40 ---------- 

41 filters : `~collections.abc.Sequence` 

42 The filters in this collection. 

43 """ 

44 

45 _defined = None 

46 """Whether these filters have been defined via 

47 `~lsst.afw.image.utils.defineFilter`. If so, set to ``self`` to identify 

48 the filter collection that defined them. 

49 """ 

50 

51 def __init__(self, *filters): 

52 self._filters = list(filters) 

53 

54 def __getitem__(self, key): 

55 return self._filters[key] 

56 

57 def __len__(self): 

58 return len(self._filters) 

59 

60 def __str__(self): 

61 return "FilterDefinitions(" + ', '.join(str(f) for f in self._filters) + ')' 

62 

63 def defineFilters(self): 

64 """Define all the filters to `lsst.afw.image.Filter`. 

65 

66 `~lsst.afw.image.Filter` objects are singletons, so we protect against 

67 filters being defined multiple times. 

68 

69 Raises 

70 ------ 

71 RuntimeError 

72 Raised if any other `FilterDefinitionCollection` has already called 

73 ``defineFilters``. 

74 """ 

75 if self._defined is None: 75 ↛ 80line 75 didn't jump to line 80, because the condition on line 75 was never false

76 self.reset() 

77 for filter in self._filters: 77 ↛ 78line 77 didn't jump to line 78, because the loop on line 77 never started

78 filter.defineFilter() 

79 FilterDefinitionCollection._defined = self 

80 elif self._defined is self: 

81 # noop: we've already defined these filters, so do nothing 

82 pass 

83 else: 

84 msg = f"afw Filters were already defined on: {self._defined}" 

85 raise RuntimeError(msg) 

86 

87 @classmethod 

88 def reset(cls): 

89 """Reset the afw Filter definitions and clear the `defined` singleton. 

90 Use this in unittests that define different filters. 

91 """ 

92 lsst.afw.image.utils.resetFilters() 

93 cls._defined = None 

94 

95 def findAll(self, name): 

96 """Return the FilterDefinitions that match a particular name. 

97 

98 This method makes no attempt to prioritize, e.g., band names over 

99 physical filter names; any definition that makes *any* reference 

100 to the name is returned. 

101 

102 Parameters 

103 ---------- 

104 name : `str` 

105 The name to search for. May be any band, physical, or alias name. 

106 

107 Returns 

108 ------- 

109 matches : `set` [`FilterDefinition`] 

110 All FilterDefinitions containing ``name`` as one of their 

111 filter names. 

112 """ 

113 matches = set() 

114 for filter in self._filters: 

115 if name == filter.physical_filter or name == filter.band or name == filter.afw_name \ 

116 or name in filter.alias: 

117 matches.add(filter) 

118 return matches 

119 

120 

121@dataclasses.dataclass(frozen=True) 

122class FilterDefinition: 

123 """The definition of an instrument's filter bandpass. 

124 

125 This class is used to interface between the `~lsst.afw.image.Filter` class 

126 and the Gen2 `~lsst.daf.persistence.CameraMapper` and Gen3 

127 `~lsst.obs.base.Instruments` and ``physical_filter``/``band`` 

128 `~lsst.daf.butler.Dimension`. 

129 

130 This class is likely temporary, until we have a better versioned filter 

131 definition system that includes complete transmission information. 

132 """ 

133 

134 physical_filter: str 

135 """The name of a filter associated with a particular instrument: unique for 

136 each piece of glass. This should match the exact filter name used in the 

137 observatory's metadata. 

138 

139 This name is used to define the ``physical_filter`` gen3 Butler Dimension. 

140 

141 If neither ``band`` or ``afw_name`` is defined, this is used 

142 as the `~lsst.afw.image.Filter` ``name``, otherwise it is added to the 

143 list of `~lsst.afw.image.Filter` aliases. 

144 """ 

145 

146 lambdaEff: float 

147 """The effective wavelength of this filter (nm).""" 

148 

149 band: str = None 

150 """The generic name of a filter not associated with a particular instrument 

151 (e.g. `r` for the SDSS Gunn r-band, which could be on SDSS, LSST, or HSC). 

152 

153 Not all filters have an abstract filter: engineering or test filters may 

154 not have a genericly-termed filter name. 

155 

156 If specified and if `afw_name` is None, this is used as the 

157 `~lsst.afw.image.Filter` ``name`` field, otherwise it is added to the list 

158 of `~lsst.afw.image.Filter` aliases. 

159 """ 

160 

161 afw_name: str = None 

162 """If not None, the name of the `~lsst.afw.image.Filter` object. 

163 

164 This is distinct from physical_filter and band to maintain 

165 backwards compatibility in some obs packages. 

166 For example, for HSC there are two distinct ``r`` and ``i`` filters, named 

167 ``r/r2`` and ``i/i2``. 

168 """ 

169 

170 lambdaMin: float = np.nan 

171 """The minimum wavelength of this filter (nm; defined as 1% throughput)""" 

172 lambdaMax: float = np.nan 

173 """The maximum wavelength of this filter (nm; defined as 1% throughput)""" 

174 

175 alias: set = frozenset() 

176 """Alternate names for this filter. These are added to the 

177 `~lsst.afw.image.Filter` alias list. 

178 """ 

179 

180 def __post_init__(self): 

181 # force alias to be immutable, so that hashing works 

182 if not isinstance(self.alias, frozenset): 

183 object.__setattr__(self, 'alias', frozenset(self.alias)) 

184 

185 def __str__(self): 

186 txt = f"FilterDefinition(physical_filter='{self.physical_filter}', lambdaEff='{self.lambdaEff}'" 

187 if self.band is not None: 

188 txt += f", band='{self.band}'" 

189 if self.afw_name is not None: 

190 txt += f", afw_name='{self.afw_name}'" 

191 if not np.isnan(self.lambdaMin): 

192 txt += f", lambdaMin='{self.lambdaMin}'" 

193 if not np.isnan(self.lambdaMax): 

194 txt += f", lambdaMax='{self.lambdaMax}'" 

195 if len(self.alias) != 0: 

196 txt += f", alias='{self.alias}'" 

197 return txt + ")" 

198 

199 def defineFilter(self): 

200 """Declare the filters via afw.image.Filter. 

201 """ 

202 aliases = set(self.alias) 

203 name = self.physical_filter 

204 if self.band is not None: 

205 name = self.band 

206 aliases.add(self.physical_filter) 

207 if self.afw_name is not None: 

208 name = self.afw_name 

209 aliases.add(self.physical_filter) 

210 # Only add `physical_filter/band` as an alias if afw_name is defined.ee 

211 if self.afw_name is not None: 

212 if self.band is not None: 

213 aliases.add(self.band) 

214 lsst.afw.image.utils.defineFilter(name, 

215 lambdaEff=self.lambdaEff, 

216 lambdaMin=self.lambdaMin, 

217 lambdaMax=self.lambdaMax, 

218 alias=sorted(aliases)) 

219 

220 def makeFilterLabel(self): 

221 """Create a complete FilterLabel for this filter. 

222 """ 

223 return lsst.afw.image.FilterLabel(band=self.band, physical=self.physical_filter)