Groups

An ORAC::Group class is responsible for dealing with groups of frame objects and with an output group data file. The most common methods that need to be sub-classed are given below.

new()

The constructor must be overridden to specify the type fixed part and file suffix of the output group file. The base constructor should be used from the subclass to instantiate the object.

readhdr()/erase()/file_exists()/file_from_bits()

Similar to the frame implementations.

For specialized applications it may also be necessary to implement the coaddswrite()/coaddsread() methods. These will be used by the CGS4/MICHELLE instrument classes to allow coadds to be combined part way through a group without having to re-reduce earlier observations. Not all instruments require support for this.