1. A non-transitory computer-accessible memory medium storing program instructions executable by a computer system to: display a graphical program, wherein the graphical program comprises a first plurality of nodes, wherein the first plurality of nodes are interconnected by a first plurality of lines visually indicating a first model of computation, and wherein the graphical program further comprises a second plurality of nodes, wherein the second plurality of nodes are interconnected by a second plurality of lines visually indicating a second model of computation that is different than the first model of computation; and generate a hardware description based on the graphical program, wherein the hardware description describes a hardware implementation of the graphical program, and wherein the hardware description is configured to configure a programmable hardware element to implement functionality of the graphical program.