Author: Stan Eisenstat
Subject: Re: [Cs323] bisection bw
Date: Wednesday, 21 Oct 2020, 09:56:41

    > Message Posted By: Unknown
    >
    > Why is bisection bandwidth for torus 2 sqrt(n)?

Here is a 4 x 4 torus with the end-to-end links omitted:

  x--x--x--x
  |  |  |  |
  x--x--x--x
  |  |  |  |
  x--x--x--x
  |  |  |  |
  x--x--x--x
  |  |  |  |
  x--x--x--x
  
To separate the two columns on the left from the two on the
right, you must cut 4 edges PLUS the 4 edges that connect
the leftmost nodes with the rightmost ones.

--Stan-