US Patent 8706847 Initiating a collective operation in a parallel computer

Initiating a collective operation in a parallel computer that includes compute nodes coupled for data communications and organized in an operational group for collective operations with one compute node assigned as a root node, including: identifying, by a non-root compute node, a collective operation to execute in the operational group of compute nodes; initiating, by the non-root compute node, execution of the collective operation amongst the compute nodes of the operational group including: sending, by the non-root compute node to one or more of the other compute nodes in the operational group, an active message, the active message including information configured to initiate execution of the collective operation amongst the compute nodes of the operational group; and executing, by the compute nodes of the operational group, the collective operation.