Coverage for python/lsst/obs/base/exposureIdInfo.py : 21%

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# This file is part of obs_base. # # Developed for the LSST Data Management System. # This product includes software developed by the LSST Project # (https://www.lsst.org). # See the COPYRIGHT file at the top-level directory of this distribution # for details of code ownership. # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see <https://www.gnu.org/licenses/>.
"""Exposure ID and number of bits used.
Attributes include:
expId exposure ID as an int expBits maximum number of bits allowed for exposure IDs maxBits maximum number of bits available for values that combine exposure ID with other information, such as source ID unusedBits maximum number of bits available for non-exposure info (maxBits - expBits)
One common use is creating an ID factory for making a source table. For example, given a data butler `butler` and a data ID `dataId`::
from lsst.afw.table import IdFactory, SourceTable exposureIdInfo = butler.get("expIdInfo", dataId) sourceIdFactory = IdFactory.makeSource(exposureIdInfo.expId, exposureIdInfo.unusedBits) schema = SourceTable.makeMinimalSchema() #...add fields to schema as desired, then... sourceTable = SourceTable.make(self.schema, sourceIdFactory)
At least one bit must be reserved, even if there is no exposure ID, for reasons that are not entirely clear (this is DM-6664). """
"""Construct an ExposureIdInfo
See the class doc string for an explanation of the arguments. """ expId = int(expId) expBits = int(expBits) maxBits = int(maxBits)
if expId.bit_length() > expBits: raise RuntimeError("expId=%s uses %s bits > expBits=%s" % (expId, expId.bit_length(), expBits)) if maxBits < expBits: raise RuntimeError("expBits=%s > maxBits=%s" % (expBits, maxBits))
self.expId = expId self.expBits = expBits self.maxBits = maxBits
def unusedBits(self): return self.maxBits - self.expBits |