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1# See COPYRIGHT file at the top of the source tree. 

2# 

3# This file is part of fgcmcal. 

4# 

5# Developed for the LSST Data Management System. 

6# This product includes software developed by the LSST Project 

7# (https://www.lsst.org). 

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

9# for details of code ownership. 

10# 

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

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

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

14# (at your option) any later version. 

15# 

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

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

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

19# GNU General Public License for more details. 

20# 

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

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

23"""Load reference catalog objects for input to FGCM. 

24 

25This task will load multi-band reference objects and apply color terms (if 

26configured). This wrapper around LoadReferenceObjects task also allows loading 

27by healpix pixel (the native pixelization of fgcm), and is self-contained so 

28the task can be called by third-party code. 

29""" 

30 

31import numpy as np 

32import healpy as hp 

33from astropy import units 

34 

35import lsst.pex.config as pexConfig 

36import lsst.pipe.base as pipeBase 

37from lsst.meas.algorithms import LoadIndexedReferenceObjectsTask, ReferenceSourceSelectorTask 

38from lsst.meas.algorithms import getRefFluxField 

39from lsst.pipe.tasks.colorterms import ColortermLibrary 

40from lsst.afw.image import abMagErrFromFluxErr 

41from lsst.meas.algorithms import ReferenceObjectLoader 

42 

43import lsst.geom 

44 

45__all__ = ['FgcmLoadReferenceCatalogConfig', 'FgcmLoadReferenceCatalogTask'] 

46 

47 

48class FgcmLoadReferenceCatalogConfig(pexConfig.Config): 

49 """Config for FgcmLoadReferenceCatalogTask""" 

50 

51 refObjLoader = pexConfig.ConfigurableField( 

52 target=LoadIndexedReferenceObjectsTask, 

53 doc="Reference object loader for photometry", 

54 ) 

55 refFilterMap = pexConfig.DictField( 

56 doc="Mapping from camera 'filterName' to reference filter name.", 

57 keytype=str, 

58 itemtype=str, 

59 default={}, 

60 ) 

61 applyColorTerms = pexConfig.Field( 

62 doc=("Apply photometric color terms to reference stars?" 

63 "Requires that colorterms be set to a ColorTermLibrary"), 

64 dtype=bool, 

65 default=True 

66 ) 

67 colorterms = pexConfig.ConfigField( 

68 doc="Library of photometric reference catalog name to color term dict.", 

69 dtype=ColortermLibrary, 

70 ) 

71 referenceSelector = pexConfig.ConfigurableField( 

72 target=ReferenceSourceSelectorTask, 

73 doc="Selection of reference sources", 

74 ) 

75 

76 def validate(self): 

77 super().validate() 

78 if not self.refFilterMap: 

79 msg = 'Must set refFilterMap' 

80 raise pexConfig.FieldValidationError(FgcmLoadReferenceCatalogConfig.refFilterMap, self, msg) 

81 if self.applyColorTerms and len(self.colorterms.data) == 0: 

82 msg = "applyColorTerms=True requires the `colorterms` field be set to a ColortermLibrary." 

83 raise pexConfig.FieldValidationError(FgcmLoadReferenceCatalogConfig.colorterms, self, msg) 

84 

85 

86class FgcmLoadReferenceCatalogTask(pipeBase.Task): 

87 """ 

88 Load multi-band reference objects from a reference catalog. 

89 

90 Parameters 

91 ---------- 

92 butler: `lsst.daf.persistence.Butler` 

93 Data butler for reading catalogs 

94 """ 

95 ConfigClass = FgcmLoadReferenceCatalogConfig 

96 _DefaultName = 'fgcmLoadReferenceCatalog' 

97 

98 def __init__(self, butler=None, refObjLoader=None, **kwargs): 

99 """Construct an FgcmLoadReferenceCatalogTask 

100 

101 Parameters 

102 ---------- 

103 butler: `lsst.daf.persistence.Buter` 

104 Data butler for reading catalogs. 

105 """ 

106 pipeBase.Task.__init__(self, **kwargs) 

107 if refObjLoader is None and butler is not None: 

108 self.makeSubtask('refObjLoader', butler=butler) 

109 else: 

110 self.refObjLoader = refObjLoader 

111 

112 self.makeSubtask('referenceSelector') 

113 self._fluxFilters = None 

114 self._fluxFields = None 

115 self._referenceFilter = None 

116 

117 def getFgcmReferenceStarsHealpix(self, nside, pixel, filterList, nest=False): 

118 """ 

119 Get a reference catalog that overlaps a healpix pixel, using multiple 

120 filters. In addition, apply colorterms if available. 

121 

122 Return format is a numpy recarray for use with fgcm, with the format: 

123 

124 dtype = ([('ra', `np.float64`), 

125 ('dec', `np.float64`), 

126 ('refMag', `np.float32`, len(filterList)), 

127 ('refMagErr', `np.float32`, len(filterList)]) 

128 

129 Reference magnitudes (AB) will be 99 for non-detections. 

130 

131 Parameters 

132 ---------- 

133 nside: `int` 

134 Healpix nside of pixel to load 

135 pixel: `int` 

136 Healpix pixel of pixel to load 

137 filterList: `list` 

138 list of `str` of camera filter names. 

139 nest: `bool`, optional 

140 Is the pixel in nest format? Default is False. 

141 

142 Returns 

143 ------- 

144 fgcmRefCat: `np.recarray` 

145 """ 

146 

147 # Determine the size of the sky circle to load 

148 theta, phi = hp.pix2ang(nside, pixel, nest=nest) 

149 center = lsst.geom.SpherePoint(phi * lsst.geom.radians, (np.pi/2. - theta) * lsst.geom.radians) 

150 

151 corners = hp.boundaries(nside, pixel, step=1, nest=nest) 

152 theta_phi = hp.vec2ang(np.transpose(corners)) 

153 

154 radius = 0.0 * lsst.geom.radians 

155 for ctheta, cphi in zip(*theta_phi): 

156 rad = center.separation(lsst.geom.SpherePoint(cphi * lsst.geom.radians, 

157 (np.pi/2. - ctheta) * lsst.geom.radians)) 

158 if (rad > radius): 

159 radius = rad 

160 

161 # Load the fgcm-format reference catalog 

162 fgcmRefCat = self.getFgcmReferenceStarsSkyCircle(center.getRa().asDegrees(), 

163 center.getDec().asDegrees(), 

164 radius.asDegrees(), 

165 filterList) 

166 catPix = hp.ang2pix(nside, np.radians(90.0 - fgcmRefCat['dec']), 

167 np.radians(fgcmRefCat['ra']), nest=nest) 

168 

169 inPix, = np.where(catPix == pixel) 

170 

171 return fgcmRefCat[inPix] 

172 

173 def getFgcmReferenceStarsSkyCircle(self, ra, dec, radius, filterList): 

174 """ 

175 Get a reference catalog that overlaps a circular sky region, using 

176 multiple filters. In addition, apply colorterms if available. 

177 

178 Return format is a numpy recarray for use with fgcm. 

179 

180 dtype = ([('ra', `np.float64`), 

181 ('dec', `np.float64`), 

182 ('refMag', `np.float32`, len(filterList)), 

183 ('refMagErr', `np.float32`, len(filterList)]) 

184 

185 Reference magnitudes (AB) will be 99 for non-detections. 

186 

187 Parameters 

188 ---------- 

189 ra: `float` 

190 ICRS right ascension, degrees. 

191 dec: `float` 

192 ICRS declination, degrees. 

193 radius: `float` 

194 Radius to search, degrees. 

195 filterList: `list` 

196 list of `str` of camera filter names. 

197 

198 Returns 

199 ------- 

200 fgcmRefCat: `np.recarray` 

201 """ 

202 

203 center = lsst.geom.SpherePoint(ra * lsst.geom.degrees, dec * lsst.geom.degrees) 

204 

205 # Check if we haev previously cached values for the fluxFields 

206 if self._fluxFilters is None or self._fluxFilters != filterList: 

207 self._determine_flux_fields(center, filterList) 

208 

209 skyCircle = self.refObjLoader.loadSkyCircle(center, 

210 radius * lsst.geom.degrees, 

211 self._referenceFilter) 

212 

213 if not skyCircle.refCat.isContiguous(): 

214 refCat = skyCircle.refCat.copy(deep=True) 

215 else: 

216 refCat = skyCircle.refCat 

217 

218 # Select on raw (uncorrected) catalog, where the errors should make more sense 

219 goodSources = self.referenceSelector.selectSources(refCat) 

220 selected = goodSources.selected 

221 

222 fgcmRefCat = np.zeros(np.sum(selected), dtype=[('ra', 'f8'), 

223 ('dec', 'f8'), 

224 ('refMag', 'f4', len(filterList)), 

225 ('refMagErr', 'f4', len(filterList))]) 

226 if fgcmRefCat.size == 0: 

227 # Return an empty catalog if we don't have any selected sources 

228 return fgcmRefCat 

229 

230 # The ra/dec native Angle format is radians 

231 # We determine the conversion from the native units (typically 

232 # radians) to degrees for the first observation. This allows us 

233 # to treate ra/dec as numpy arrays rather than Angles, which would 

234 # be approximately 600x slower. 

235 

236 conv = refCat[0]['coord_ra'].asDegrees() / float(refCat[0]['coord_ra']) 

237 fgcmRefCat['ra'] = refCat['coord_ra'][selected] * conv 

238 fgcmRefCat['dec'] = refCat['coord_dec'][selected] * conv 

239 

240 # Default (unset) values are 99.0 

241 fgcmRefCat['refMag'][:, :] = 99.0 

242 fgcmRefCat['refMagErr'][:, :] = 99.0 

243 

244 if self.config.applyColorTerms: 

245 if isinstance(self.refObjLoader, ReferenceObjectLoader): 

246 # Gen3 

247 refCatName = self.refObjLoader.config.value.ref_dataset_name 

248 else: 

249 # Gen2 

250 refCatName = self.refObjLoader.ref_dataset_name 

251 

252 for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters, self._fluxFields)): 

253 if fluxField is None: 

254 continue 

255 

256 self.log.debug("Applying color terms for filtername=%r" % (filterName)) 

257 

258 colorterm = self.config.colorterms.getColorterm( 

259 filterName=filterName, photoCatName=refCatName, doRaise=True) 

260 

261 refMag, refMagErr = colorterm.getCorrectedMagnitudes(refCat, filterName) 

262 

263 # nan_to_num replaces nans with zeros, and this ensures that we select 

264 # magnitudes that both filter out nans and are not very large (corresponding 

265 # to very small fluxes), as "99" is a common sentinel for illegal magnitudes. 

266 

267 good, = np.where((np.nan_to_num(refMag[selected]) < 90.0) 

268 & (np.nan_to_num(refMagErr[selected]) < 90.0) 

269 & (np.nan_to_num(refMagErr[selected]) > 0.0)) 

270 

271 fgcmRefCat['refMag'][good, i] = refMag[selected][good] 

272 fgcmRefCat['refMagErr'][good, i] = refMagErr[selected][good] 

273 

274 else: 

275 # No colorterms 

276 

277 for i, (filterName, fluxField) in enumerate(zip(self._fluxFilters, self._fluxFields)): 

278 # nan_to_num replaces nans with zeros, and this ensures that we select 

279 # fluxes that both filter out nans and are positive. 

280 good, = np.where((np.nan_to_num(refCat[fluxField][selected]) > 0.0) 

281 & (np.nan_to_num(refCat[fluxField+'Err'][selected]) > 0.0)) 

282 refMag = (refCat[fluxField][selected][good] * units.nJy).to_value(units.ABmag) 

283 refMagErr = abMagErrFromFluxErr(refCat[fluxField+'Err'][selected][good], 

284 refCat[fluxField][selected][good]) 

285 fgcmRefCat['refMag'][good, i] = refMag 

286 fgcmRefCat['refMagErr'][good, i] = refMagErr 

287 

288 return fgcmRefCat 

289 

290 def _determine_flux_fields(self, center, filterList): 

291 """ 

292 Determine the flux field names for a reference catalog. 

293 

294 Will set self._fluxFields, self._referenceFilter. 

295 

296 Parameters 

297 ---------- 

298 center: `lsst.geom.SpherePoint` 

299 The center around which to load test sources. 

300 filterList: `list` 

301 list of `str` of camera filter names. 

302 """ 

303 

304 # Record self._fluxFilters for checks on subsequent calls 

305 self._fluxFilters = filterList 

306 

307 # Search for a good filter to use to load the reference catalog 

308 # via the refObjLoader task which requires a valid filterName 

309 foundReferenceFilter = False 

310 for filterName in filterList: 

311 refFilterName = self.config.refFilterMap.get(filterName) 

312 if refFilterName is None: 

313 continue 

314 

315 try: 

316 results = self.refObjLoader.loadSkyCircle(center, 

317 0.05 * lsst.geom.degrees, 

318 refFilterName) 

319 foundReferenceFilter = True 

320 self._referenceFilter = refFilterName 

321 break 

322 except RuntimeError: 

323 # This just means that the filterName wasn't listed 

324 # in the reference catalog. This is okay. 

325 pass 

326 

327 if not foundReferenceFilter: 

328 raise RuntimeError("Could not find any valid flux field(s) %s" % 

329 (", ".join(filterList))) 

330 

331 # Retrieve all the fluxField names 

332 self._fluxFields = [] 

333 for filterName in filterList: 

334 fluxField = None 

335 

336 refFilterName = self.config.refFilterMap.get(filterName) 

337 

338 if refFilterName is not None: 

339 try: 

340 fluxField = getRefFluxField(results.refCat.schema, filterName=refFilterName) 

341 except RuntimeError: 

342 # This flux field isn't available. Set to None 

343 fluxField = None 

344 

345 if fluxField is None: 

346 self.log.warn(f'No reference flux field for camera filter {filterName}') 

347 

348 self._fluxFields.append(fluxField)