The Pierre Auger Observatory offline software

The Pierre Auger Observatory aims to discover the nature and origins of the 24 highest energy cosmic rays. The large number of physicists involved in the project and 25 the diversity of simulation and reconstruction tasks pose a challenge for the offline analysis 26 software, not unlike the challenges confronting software for very large high energy physics 27 experiments. Previously we have reported on the design and implementation of a general 28 purpose but relatively lightweight framework which allows collaborators to contribute algorithms 29 and sequencing instructions to build up the variety of applications they require. In this report, 30 we update the status of this work and describe some of the successes and difficulties encountered 31 over the last few years of use. We explain the machinery used to manage user contributions, 32 to organize the abundance of configuration files, to facilitate multi-format file handling, and 33 to provide access to event and time-dependent detector information residing in various data 34 sources. We also describe the testing procedures used to help maintain stability of the code in 35 the face of a large number of contributions. Foundation classes will also be discussed, including a 36 novel geometry package which allows manipulation of abstract geometrical objects independent 37 of coordinate system choice. 38