1. Logic for scheduling in a high-performance computing (HPC) system, the logic encoded in a computer-readable medium and when executed operable to: receive a call from a management engine operable to manage a cluster of nodes in the HPC system, the call specifying a request comprising a job for scheduling comprising one or more processes for execution at one or more nodes in the cluster, the call further specifying a number of nodes for executing the job; determine whether the request is spatial, compact, or nonspatial and noncompact, the request being spatial if the job assumes spatial relationships between nodes executing the job, the request being compact if the job assumes proximity between nodes executing the job, the request being nonspatial and noncompact if the job assumes no spatial relationships or proximity between nodes executing the job; if the request is spatial: generate one or more spatial combinations of nodes in the cluster accommodating the number of nodes specified in the call and further accommodating the assumed spatial relationships between nodes executing the job; and select one of the spatial combinations that is schedulable according to a list of nodes in the cluster available for scheduling; if the request is compact: generate one or more compact combinations of nodes in the cluster accommodating the number of nodes specified in the call; and select one of the compact combinations that is schedulable according to the list of nodes in the cluster available for scheduling and that is more compact than other compact combinations that are schedulable according to the list of nodes in the cluster available for scheduling; if the request is nonspatial and noncompact: identify one or more nodes schedulable according to the list of nodes in the cluster available for scheduling; and generate a nonspatial and noncompact combination of nodes in the cluster accommodating the number of nodes specified in the call, the nonspatial and noncompact combination comprising one or more of the one or more identified nodes that are schedulable according to the list of nodes in the cluster available for scheduling; and communicate a return to the management engine identifying one or more nodes in the selected spatial, compact, or nonspatial and noncompact combination of nodes in the cluster for executing the job.