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Preliminary Look

Preliminary Look. Steven Pieper’s Quantum Monte Carlo Code. What is the code? As far as I can tell…. Quantum Monte Carlo Generate input file Chomp (all the time) Solving wave equation/minimizing potentials Send minimized nuclei to master Possible: redist work Synchronize

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Preliminary Look

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  1. Preliminary Look Steven Pieper’s Quantum Monte Carlo Code

  2. What is the code?As far as I can tell… • Quantum Monte Carlo • Generate input file • Chomp (all the time) • Solving wave equation/minimizing potentials • Send minimized nuclei to master • Possible: redist work • Synchronize • Lots of repetition

  3. Help from the source • Profiling pre-exists • Time, FLOPS, memory • Memory is just IBM/Mac • FLOPS counts in code • MPI • Tracks the amount communicated in messages

  4. How does it perform? • Computation takes from 80%-95% of wall clock time • MPI is very simple • One whole nucleus per proc • Memory Limitation • Keeps MPI costs very low • i.e. can run on ethernet • So, it scales quite well.

  5. Basic Algorithm • Init fbn wave function • Init some positions (randomly) • Init wave functions and probability density • Propogate time/synchronize procs

  6. Number Total msec/ Flop/ MFLOPS of cases min. case case Wavefunctions 670250 1.8 0.163 165499 1014.881 2-body Prop. 0 0.0 0.000 0 0.000 3-body Prop. & Vijk 0 0.0 0.000 0 0.000 Propagation step 0 0.0 0.000 0 0.000 Other Propagation 0 0.0 0.000 0 0.000 Other vij 0 0.0 0.000 0 0.000 Total accounted for time: 110926. MFLOP 1.8 Min 1014.881 MFLOPS MFLOP/Wall-second: 2857.285 96.1% of total compute time is accounted for ….. Master got 53.45 Mbytes = 1.3767 Mbytes/sec Master sent 0.00 Mbytes = 0.0000 Mbytes/sec Master got 30005 messages = 772.8822 messages/sec

  7. Totals for all slaves Num Cases Total Time Time/case Min. Sec. Propagation 4059060 116.9 0.002 Branching 379 0.0 0.003 Energies 223050 59.2 0.016 Kinetic 22.2 0.006 2-b Potential 31.9 0.009 3-b Potential 4.4 0.001 Densities 0.7 0.000 Other compute 223050 0.3 0.000 All compute 223050 176.4 0.047 Config. write (wall) 223050 6.7 0.002 Above include Number Total msec/ Flop/ MFLOPS of cases min. case case Wavefunctions 22612208 62.2 0.165 165031 1000.523 2-body Prop. 4059060 39.8 0.588 324854 552.399 3-body Prop. & Vijk 4282110 60.1 0.842 805563 957.102 Propagation step 4059060 7.9 0.117 34435 293.892 Other Propagation 4059060 0.6 0.009 2115 237.629 Other vij 223050 4.7 1.251 1210116 967.236

  8. Total accounted for time: 8918108. MFLOP 175.2 Min 848.397 MFLOPS MFLOP/Wall-second: 15321.884 99.3% of total compute time is accounted for Master got 505.62 Mbytes = 0.8687 Mbytes/sec Master sent 5.21 Mbytes = 0.0089 Mbytes/sec Master got 223639 messages = 384.2262 messages/sec Master wall min. in loop 9.7 Master idle wall min. 9.4 Total available wall min. 184.3 Total compute min. 176.4 Efficency 95.7% Speed up 18.2

  9. Data Structures • Pretty straight forward arrays • Wave function solution on the grid • Grows 2** with number of particle • Quickly moves from FLOPS to memory bound

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