Questions for 6.S897 lecture 18 (Graphs, 11/17).
Email your answers to 6.s897staff@gmail.com.
1) Why does the greedy graph coloring in the PowerGraph paper not converge if PowerGraph runs in synchronous mode?
2) Each iteration of PageRank is similar to sparse matrix-vector multiply (SpMV), which was analyzed in the roofline performance paper. Estimate the FLOPS and memory bandwidth used by Ligra on the Twitter graph and compare it to numbers in the Roofline paper.