Towards PPCC

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Towards PPCC

• So Hirata
• Quantum Theory Project
• University of Florida

Sanibel Symposium 2008, Parallel CC Workshop
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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

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Automated symbolic algebraHirata, JPCA (2003)
Hirata, TCA (2006) Hirata, JP Conf. Ser. (2006)
Definition of a many-electron theory
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Automated symbolic algebraHirata, JPCA (2003)
Hirata, TCA (2006) Hirata, JP Conf. Ser. (2006)

• 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 machines job
Agent Smith The Matrix
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Implemented methodsHirata JPCA (2003) Hirata
TCA (2006) Hirata JP Conf Ser (2006)
Electron Attachment Theory EA-EOM-CCSD EA-EOM-CCSD
T EA-EOM-CCSDTQ Kamiya Hirata (2007)
Linear Expansion CIS, CISD, CISDT, CISDTQ Hirata
JPCA (2003)
CI
CISperturbation CIS(D), CIS(3), CIS(4) Hirata
JCP (2005)
Ionization Theory IP-EOM-CCSD IP-EOM-CCSDT IP-EOM-
CCSDTQ Kamiya Hirata JCP (2006)
Other CIS2nd order D-CIS(2), SCS-CIS(D) SOS-CIS(D
) Fan Hirata (2007)
Excited State Theories EOM-CCSD EOM-CCSDT EOM-CCSD
TQ Hirata JCP (2004)
Perturbation MP2, MP3, MP4 Hirata JPCA (2003)
PT
CC
Combined CCPT 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)
Cluster Expansion CCD, CCSD, CCSDT, CCSDTQ,
LCCD, LCCSD, QCISD Hirata JPCA (2003)
EOM-CCperturbation EOM-CCSD(2)T,
EOM-CCSD(2)TQ EOM-CCSD(3)T Shiozaki, Hirao
Hirata JCP (2007)
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CC-R12, EOM-CC-R12, ?-CC-R12Shiozaki, Kamiya,
Hirata, Valeev, in preparation (2008)
New types of ansatz new symbolic algabra
code Significantly more complex equations Longer
computational sequences Multiple
hotspots Possibilities of various approximations
Toru Shiozaki University of Florida
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CC-R12
R12-CCSD on 100 processors CCSD on 100,000
processors
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Linear scaling CC
Linear scaling CCSD on 1 processor CCSD on
100,000 processors
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Fast methods for water clustersHirata et al. MP
(2005)
Pair energy in the presence of dipole field
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Fast methods excited statesHirata et al. MP
(2005)
A record EOM-CCSD aug-cc-pVDZ calculation for a
247-atom system
Constant scaling!
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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.

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?1 and ?2 type solid formic acid
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Molecular crystals
Hydrogen fluoride
Formamide
Ice XI