[ODK] Meeting 2018 10 10

Minutes for the October 10, 2018 meeting

Zhu et Alexis: install/update issues on luke server (due to an update of some libraries?)
Alexis:
- Finished using serialization in mpi-comm-interface
- Blas communication matrix/vector simplification (WIP)
Zhu:
- New timings, ~30bits integers, on dahu and luke (see table below)
- sharing A and B are not taken in account for timings
- bigger matrices cause RAM and comm troubles
- How to split to different nodes?

Matrix size	CRA Solve + Recon	Cores	Machine
2000x2000	~7min	60	luke42
2000x2000	~8min	40	luke42
2000x2000	~9min	20	luke42
2000x2000	~7min	20	dahu36
4000x4000	~66min	60	luke42
4000x4000	~70min	40	luke42

For Zhu, generate the matrix once and write it to a file, just read that file. So that comparisons are reproductible.

Clement, asking for granularity timings:
- time initial broadcast (A and B)
- time A mod pi and B mod pi computation
- time for each solve mod pi
- use timestamp for begin and end
Clement, asking for optimizations:
- currently EarlyMultipRatCRA is used (solve.h), better try FullMultipRatCRA, otherwise master can be overloaded and workers won't have any task.
- FullMultipRatCRA requires a BOUND, expressed as a double, which seems strange. Moreover, it's a natural log, why not log2?
  - Currently, we should pass log(HadamardBound(A, B)).
  - Hadamard: n/2.0*(log(double(n))+2*log(double(max)));