TPhTopology - an introduction

TPhTopology is a means to describe a detector configuration which allows a virtual partition of a flat data array into segments that correspond to various levels. The only constraint is that all of the nodes at the "bottom" of the tree are at the same depth relative to the root node.

The bottom nodes comprise one or more channels. The nodes above it comprise all of the channels of the nodes beneath it.

The topology does not itself contain any data. Instead, it serves as merely the directory which allows the user to get access to the data by reference to a subcomponent, or even just simple access to all of the channels.

The important objects here are:

• TPhTopology The root topology is a topology. However, each node of the root is itself a topology, as are all of its nodes, etc.
• TPhTopoIter This is an iterator to a topology at a certain depth. If t is a TPhTopology, then t->Begin(2) gives a TPhTopoIter at depth 2 (2 levels down from root, or 1 in the above diagram). The iterator is able to skip over the structures defined above it. Thus, one can iterate over all of the "1"'s without knowing the structure of the "2"'s above them.
• TPhTopoPtr This is a RefPtr (smart pointer) to a topology. This is used to place the responsibility of whether a topology should be deleted with the topology itself. Just think of this as a TPhTopology* and everything should be fine!

Finally, keep in mind that you will not use TPhTopology directly. Rather, the TPhTopoData objects will access its topology for you by forwarding your requests to it. See the documentation in TPhTopoData.cxx for some more explanation of this.