1. A non-transitory computer-accessible memory medium comprising program instructions, wherein the program instructions are executable to: receive a graphical program that simulates a physical system, wherein the graphical program comprises: a first graphical program portion comprising a first plurality of nodes and first connections for simulating a first portion of the physical system, wherein the first plurality of nodes represent first physical components and wherein the first connections represent physical connectivity between the first physical components, wherein the first graphical program portion is specified according to a first physical domain; a second graphical program portion comprising a second plurality of nodes and second connections for simulating a second portion of the physical system, wherein the second plurality of nodes represent second physical components and wherein the second connections represent physical connectivity between the second physical components, wherein the second graphical program portion is specified according to a second physical domain; generate a hardware description based on the graphical program, wherein the hardware description describes a hardware implementation of the first graphical program portion and the second graphical program portion of the graphical program, and wherein the hardware description is configured to configure a programmable hardware element to simulate the physical system.