Towards PPCC So Hirata Quantum Theory Project University of Florida Sanibel Symposium 2008, Parallel...
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Transcript of Towards PPCC So Hirata Quantum Theory Project University of Florida Sanibel Symposium 2008, Parallel...
Towards PPCC
So HirataQuantum Theory Project
University of Florida
Sanibel Symposium 2008, Parallel CC Workshop
Issues at petascale Increased complexity of algorithms and
implementations – computerized derivation and implementation / optimization, portability, extensibility, maintainability / parallel middleware
Multilevel hierarchical parallelism – hierarchical structures of chemical computing / linear scaling, PES scan, ab initio MD/MC
Fault tolerance, restart capability, calculation log, and verification – parallel middleware / compartmentation of calculations / redundant calculations / hierarchical methods
Automated symbolic algebraHirata, JPCA (2003); Hirata, TCA (2006); Hirata, JP Conf. Ser. (2006)
Definition of a many-electron theory 0 1 2 0 1 2 0 1 2 0exp ; 0 exp ; 0 expa ab
i ijC C CE H T T H T T H T T
Mathematical expressions
A parallel computer program
Automated symbolic algebraHirata, JPCA (2003); Hirata, TCA (2006); Hirata, JP Conf. Ser. (2006)
Agent Smith“The Matrix”
Correct scaling by factorized, reusable intermediates
Spin, point-group, and permutation symmetries
Dynamic load balancing parallelism; scalable
Runtime adjustment of memory usage
Never send a human to do a machine’s job
Implemented methodsHirata JPCA (2003); Hirata TCA (2006); Hirata JP Conf Ser (2006)
CI
PTCC Combined CC+PT
CCSD(T)CCSD(2)T, CCSD(3)T
CCSD(2)TQ, CCSD(3)TQ
CCSDT(2)Q, CR-CCSD(T)Hirata et al. JCP (2004)
Shiozaki, Hirao & Hirata JCP (2007)
Linear ExpansionCIS, CISD, CISDT, CISDTQ
Hirata JPCA (2003)
CIS+perturbationCIS(D), CIS(3), CIS(4)
Hirata JCP (2005)
PerturbationMP2, MP3, MP4
Hirata JPCA (2003)
Excited State TheoriesEOM-CCSD
EOM-CCSDTEOM-CCSDTQ
Hirata JCP (2004)
Ionization TheoryIP-EOM-CCSD
IP-EOM-CCSDTIP-EOM-CCSDTQKamiya & Hirata JCP (2006)
Cluster ExpansionCCD, CCSD, CCSDT,
CCSDTQ, LCCD,LCCSD, QCISD
Hirata JPCA (2003)
Electron Attachment TheoryEA-EOM-CCSD
EA-EOM-CCSDTEA-EOM-CCSDTQ
Kamiya & Hirata (2007)
EOM-CC+perturbationEOM-CCSD(2)T, EOM-CCSD(2)TQ
EOM-CCSD(3)TShiozaki, Hirao & Hirata JCP (2007)
Other CIS+2nd orderD-CIS(2), SCS-CIS(D)
SOS-CIS(D)Fan & Hirata (2007)
CC-R12, EOM-CC-R12, Λ-CC-R12Shiozaki, Kamiya, Hirata, & Valeev, in preparation (2008)
Toru ShiozakiUniversity of Florida
New types of ansatz – new symbolic algabra codeSignificantly more complex equationsLonger computational sequencesMultiple hotspotsPossibilities of various approximations
Fast methods for water clustersHirata et al. MP (2005)
n n
ij i j ii j i
E E E E E
Pair energy in the presence of dipole field
N-body (N > 2) Coulomb in dipole-dipole approximation
1 and 2-bodyCoulombExchangeCorrelation
Fast methods: excited statesHirata et al. MP (2005)
A record EOM-CCSD aug-cc-pVDZ calculation for a 247-atom system
0 5 10 15 20
Number of monomer units
CP
U t
ime
(arb
itrar
y un
its)
Conventional
Pair interaction (no cutoff)
Pair interaction (cutoff at 30 bohr)
Constant scaling!
Coupled-cluster for solids
Maddox (Nature, 1988): “One of the continuing scandals in the physical sciences is that it remains in general impossible to predict the structure of even the simplest crystalline solids from a knowledge of their chemical composition. … Solids such as crystalline water (ice) are still thought to lie beyond mortals’ ken.”