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Recent Progress on ISAT

Recent Progress on ISAT. Stephen B. Pope January 25, 2007. Research Group Meetings. Practice talks e.g. for upcoming Combustion Institute meeting Report and discussion of recent research. In Situ Adaptive Tabulation. Particle methods 10 10 particle steps

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Recent Progress on ISAT

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  1. Recent Progress on ISAT Stephen B. Pope January 25, 2007

  2. Research Group Meetings • Practice talks • e.g. for upcoming Combustion Institute meeting • Report and discussion of recent research

  3. In Situ Adaptive Tabulation • Particle methods • 1010 particle steps • Reaction sub-step: direct integration 104ms • 108 s = 3.2 years • X 1,000 speed-up -> 28 hrs • ISAT • Tabulate results of ODE integration

  4. ISAT-CK 5.1 • Primary retrieve • BT, MRU, MFU • Secondary retrieve • EBT in affine space • can afford to be complete • Grow • EOA/EOI • EBT • Add • EOI initialized to exclude existing points

  5. Very Recent Additions • de_nearby • Location (x) of direct evaluation may be slightly different from the query location • Needed for ICE-PIC/ISAT • “Slow progress” • Query time > DE time • Reduce growing • Worst case: query time = 2 x DE time

  6. Preliminary Testing of ISAT-CK 5.1 • Systematic testing to be performed by Liuyan • Study performance as function of parameters • Error tolerance • Available storage

  7. Test YF: varying error tolerance • Skeletal mechanism (16 species) • CPU for DI =5,000 ms • Premixed • Storage = 1.2 Gbytes • Idites=1000 (affects performance) • Q=107 • Etol=2-p, p=1,2,…,32

  8. CDF of error for etol=1.2e-4

  9. Test YF: observations • Error well controlled down to 1e-8: confirmed that errors due to ODE • Timing affected by error testing • Speed-up on table filling

  10. Test YH: varying number of leaves • Skeletal mechanism (16 species) • CPU for DI =5,000 ms • Premixed • Q=107 • Etol=10-4 • Leaves = 16, 32, 64,…,2048.

  11. Test YH: observations • As storage decreases, query time tends to DE time • “Slow progress” avoids excessive CPU time • “slow progress” if query time > DE time • Ret_frac set to ½ • Grow_frac set to ½ • EOIs not shrunk

  12. Test YA: varying error tolerance • GRI 3.0 mechanism (53 species) • CPU for DI =80,000 ms (x16 cf skeletal) • Premixed • Storage = 1.2 Gbytes • Idites=1000 (affects performance) • Q=108 • Etol=2-p, p=1,2,…,19

  13. Test YA: Observations • Error well controlled • Even for smallest etol, retrieves dominate in the end; but it takes longer to reach retrieving asymptote

  14. Test K: Dim. Of Affine Space • Skeletal mechanism (16 species) • Premixed • Storage = 1.0 Gbytes • Idites=1000 (affects performance) • Q=1e7 • Etol=1e-3 • Affine space, na=1,2,3,…15

  15. Test M: Pair Cover • Skeletal mechanism (16 species) • Premixed • Storage = 2.5 Gbytes • Idites=1000 (affects performance) • Q=1e7 • Etol=1e-4 • Pair_cover: type of ellipsoid used to cover two other ellipsoids (in EBT) • 1 – spheroid (no shrinking) • 2 – ellipsoid (covariance algorithm) • 3 – ellipsoid (iterative algorithm) • 4 – spheroid (with shrinking)

  16. Test YJ: storage and etol • Skeletal mechanism (16 species) • Premixed • Idites=10,000 Q=1e7 • Etol = 4-p = 1, ¼, 1/16,…,1.5e-5 • Leaves = 4q = 16, 64, 256,…,16,384

  17. Test YI: varying etol • Skeletal mechanism (16 species) • CPU for DI =5e3 ms • Non-premixed, variable time step • Idites=10,000 Q=1e8 • Storage = 1.2 Gbytes • etola = 1, 1/2,...3e-5

  18. Future Plans: ISATAB • Single precision for ellipsoids • x2f_mpi • ISAT/ANN

  19. Future Plans: ISAT-CK • ICE-PIC • CEQ in place of Stanjan • ADIFOR for Jacobians • LP for realizability • Conservation correction for sensitivity matrix

  20. Future Plans: papers • Pope (2007) – new algorithms • Lu & Pope (2007) – performance of ISAT • Lu, Lantz, Ren, Pope (2007) – x2f_mpi • Ren & Pope (2007) – ICE-PIC/ISAT

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