Topology mapping in a distributed processing system, the distributed processing system including a plurality of compute nodes, each compute node having a plurality of tasks, each task assigned a unique rank, including: assigning each task to a geometry defining the resources available to the task; selecting, from a list of possible data communications algorithms, one or more algorithms configured for the assigned geometry; and identifying, by each task to all other tasks, the selected data communications algorithms of each task in a single collective operation.