US Patent 9424079 Iteration support in a heterogeneous dataflow engine

Various embodiments provide techniques and constructs to improve execution speed of distributed iterative computation using heterogeneous specialized resources including, for example, processors and accelerators. Iteration over an arbitrary sub-graph without loop unrolling including for algorithms with data-dependent loop termination and large iteration counts, including as a result of nested iteration, are supported in a resource-efficient manner without adding vertices to a dataflow graph to represent iteration constructs. Instead, some or all of the existing vertices within the sub-graph that is to be iterated upon based on having additional and/or modified ports and channels associated with them.