Hi Erik,
We evolve alpha and beta for the gauge variables as given in equations 7a and 7b of http://arxiv.org/pdf/1506.06153.pdf. The number I reported for LazEv was using 5th order dissipation applied to all 21 evolved variables (alp, beta^i, At_{ij}, gt_{ij}, Gammat^{i}, trK, and xi).
LazEv is calculating the Hamiltonian and Momentum constraints as well as the constraints on Gammat^i using 4th order stencils.
I also forgot to mention that I did these tests on 16 nodes, and the memory usage was relatively low ( ~2 GB/MPI process ).
I will give the internal dissipation for McLachlan a try.
Thanks, Jim
On 07/27/2015 05:56 PM, Erik Schnetter wrote:
Jim
Thanks for posting the details.
Can you give us more details about the LazEv scheme? In particular there may be differences in the gauge. What (gauge) variables do you evolve? What gauge conditions do you use? And what kind of dissipation do you apply? Can you point us to the source code?
For the new McLachlan, you would probably use the built-in dissipation instead of thorn Dissipation, which should lead to a small speed-up.
-erik
On Mon, Jul 27, 2015 at 4:43 PM, James Healy <jchsma@rit.edu mailto:jchsma@rit.edu> wrote:
Hello, I have been running some tests on Stampede comparing the run speed of McLachlan to RIT's evolution thorn LazEv. I started with the qc0-mclachlan.par parameter file included with the Einstein Toolkit, added a few refinement levels, increased the resolution and changed McLachlan to be 8th order (and increased the number of ghost zones to 5). I also increased the initial separation so the finest grids aren't already overlapping. To compare with LazEv, I removed the McLachlan and Dissipation thorns and replaced them with LazEv. Everything else in the parameter file is exactly the same. I tried using both the McLachlan master and rewrite branches. The grid setup is 10 levels of refinement, dx=4M on the coarsest with outer boundary at 400M, M/128 on the finest with r=0.6M, CFL is 0.25. Both use 8th order spatial differencing with ghost_size=5 and 5th order dissipation. Below is a summary of the results as reported at iteration 256 from Carpet::physical_time_per_hour: McLachlan - rewrite branch: 3.0596110 M/hr McLachlan - master branch: 3.8033607 M/hr LazEv - 4.1941544 M/hr I am using the stampede-impi.cfg configuration file in simfactory. "module list" returns: 1) TACC-paths 3) cluster-paths 5) xalt/0.4.6 7) TACC 2) Linux 4) intel/13.0.2.146 <http://13.0.2.146> 6) cluster 8) impi/4.1.0.030 <http://4.1.0.030> Attached is my parameter file. I pasted the McLachlan parameters below. Are there any optimizations that I can use for McLachlan? Are the parameters I am using for it what would be used for production runs? ML_BSSN::harmonicN = 1 # 1+log ML_BSSN::harmonicF = 2.0 # 1+log ML_BSSN::ShiftGammaCoeff = 0.75 ML_BSSN::BetaDriver = 1.0 ML_BSSN::LapseAdvectionCoeff = 1.0 ML_BSSN::ShiftAdvectionCoeff = 1.0 ML_BSSN::MinimumLapse = 1.0e-8 ML_BSSN::my_initial_boundary_condition = "extrapolate-gammas" ML_BSSN::my_rhs_boundary_condition = "NewRad" Boundary::radpower = 2 ML_BSSN::ML_log_confac_bound = "none" ML_BSSN::ML_metric_bound = "none" ML_BSSN::ML_Gamma_bound = "none" ML_BSSN::ML_trace_curv_bound = "none" ML_BSSN::ML_curv_bound = "none" ML_BSSN::ML_lapse_bound = "none" ML_BSSN::ML_dtlapse_bound = "none" ML_BSSN::ML_shift_bound = "none" ML_BSSN::ML_dtshift_bound = "none" ML_BSSN::fdOrder = 8 ActiveThorns = "Dissipation" Dissipation::order = 5 Dissipation::vars = " ML_BSSN::ML_metric ML_BSSN::ML_trace_curv ML_BSSN::ML_curv ML_BSSN::ML_Gamma ML_BSSN::ML_lapse ML_BSSN::ML_shift ML_BSSN::ML_dtlapse ML_BSSN::ML_dtshift " ActiveThorns = "ML_ADMConstraints" Thanks, Jim Healy _______________________________________________ Users mailing list Users@einsteintoolkit.org <mailto:Users@einsteintoolkit.org> http://lists.einsteintoolkit.org/mailman/listinfo/users-- Erik Schnetter <schnetter@cct.lsu.edu mailto:schnetter@cct.lsu.edu> http://www.perimeterinstitute.ca/personal/eschnetter/