These m-files are related to a claim we make in a recently submitted paper
that PPCD converges faster than GCD.
Although it is difficulty to show that claim analytically,
the m-files in this directory give empirical evidence of that claim.

Note: you must be patient when executing this code!

Note to me:
The m-files for testing are in /n/ir4/x/ssotthiv/blockCD/mpi/2d/.
16x16 GCD and 16-PPCD take more time to run.
Comparing only 4x4 GCD, 4-PPCD, and CD takes about 10 mins.