Graph theory and computer chip design reference Wikipedia says graph theory is used in computer chip design. 

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Is there a good reference for that? I can imagine optimal way to draw cpu to chip is to draw shortest hamiltonian cycle in it.
 A: As copper.hat said, it's difficult to determine what you mean by "a good reference". There are so many applications of graph theory in "computer chip design". Here's a smattering of starting places:


*

*Topology in electrical circuits

*Network analysis in electrical circuits

*Hypercube Multiprocessors, 1987:
Proceedings of the Second Conference on Hypercube Multiprocessors, Knoxville, Tennessee, September 29-October 1, 1986

*Saad, Youcef, and Martin H. Schultz. "Topological properties of hypercubes." Computers, IEEE Transactions on 37.7 (1988): 867-872.

*Electric Circuits & Networks
By K. S. Suresh Kumar, Kumar K. S. Suresh: 770-777.

*Cederbaum, I.; , "Some applications of graph theory to network analysis and synthesis," Circuits and Systems, IEEE Transactions on , vol.31, no.1, pp. 64- 68, Jan 1984
A: I'm not sure what would constitute a good reference given the breadth of applications of graph theory in integrated circuit design.
You could glance at the floorplanning, placement and routing chapters of  Smith's "Application specific integrated circuits" to get a feel for what is involved. It is an old book (1997) but gives a decent, fairly concise overview.
However, the term 'optimal' is hard to characterize in terms of cpu design, there are many conflicting objectives that need to be addressed. The old adage was "power, speed, area - pick two". Design (in the broad sense) has become considerably more complicated since those relatively simple days.
A: You might find this article of use: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.154.2278
A: I don't know about a reference. However, the intuition is that an electrical circuit in a computer chip design is etched into a flat surface. This implies that the graph model of this circuit must be a planar graph. So the theory behind planar graphs is very important in designing such circuits.
