Recent Progress on ISAT
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Transcript of 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– 1010 particle steps– Reaction sub-step: direct integration 104 s– 108 s = 3.2 years– X 1,000 speed-up -> 28 hrs
• ISAT– Tabulate results of ODE integration
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
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
Preliminary Testing of ISAT-CK 5.1
• Systematic testing to be performed by Liuyan
• Study performance as function of parameters– Error tolerance– Available storage
Test YF: varying error tolerance
• Skeletal mechanism (16 species)– CPU for DI =5,000 s
• Premixed
• Storage = 1.2 Gbytes
• Idites=1000 (affects performance)
• Q=107
• Etol=2-p, p=1,2,…,32
CDF of error for etol=1.2e-4
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
Test YH: varying number of leaves
• Skeletal mechanism (16 species)– CPU for DI =5,000 s
• Premixed
• Q=107
• Etol=10-4
• Leaves = 16, 32, 64,…,2048.
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
Test YA: varying error tolerance
• GRI 3.0 mechanism (53 species)– CPU for DI =80,000 s (x16 cf skeletal)
• Premixed
• Storage = 1.2 Gbytes
• Idites=1000 (affects performance)
• Q=108
• Etol=2-p, p=1,2,…,19
Test YA: Observations
• Error well controlled
• Even for smallest etol, retrieves dominate in the end; but it takes longer to reach retrieving asymptote
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
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)
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
Test YI: varying etol
• Skeletal mechanism (16 species)– CPU for DI =5e3 s
• Non-premixed, variable time step
• Idites=10,000 Q=1e8
• Storage = 1.2 Gbytes
• etola = 1, 1/2,...3e-5
Future Plans: ISATAB
• Single precision for ellipsoids
• x2f_mpi
• ISAT/ANN
Future Plans: ISAT-CK
• ICE-PIC
• CEQ in place of Stanjan
• ADIFOR for Jacobians
• LP for realizability
• Conservation correction for sensitivity matrix
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