Special Cases and Applications
Random arrangement of logic blocks typically have . Larger values are impossible since the maximum number of terminals for any region containing g logic components in a homogeneous system is given by . Lower bounds on p depend on the interconnection topology since it is generally impossible to make all wires short. This lower bound is often called the "intrinsic Rent exponent", a notion first introduced by Hagen et al. It can be used to characterize optimal placements and also measure the interconnection complexity of a circuit. Higher (intrinsic) Rent exponent values correspond to a higher topological complexity. One extreme example is a long chain of logic blocks, while a clique has . In realistic 2D circuits, ranges from 0.5 for highly-regular circuits (such as SRAM) to 0.75 for random logic.
System performance analysis tools such as BACPAC typically use Rent's rule to calculate expected wiring lengths and wiring demands.
Read more about this topic: Rent's Rule
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