1. Towards PPCC So Hirata Quantum Theory Project University of Florida Sanibel Symposium 2008, Parallel CC Workshop

2. 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

3. Automated symbolic algebra Hirata, JPCA (2003); Hirata, TCA (2006); Hirata, JP Conf. Ser. (2006) Definition of a many-electron theory Mathematical expressions A parallel computer program

4. Automated symbolic algebra Hirata, 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

5. Implemented methods Hirata JPCA (2003); Hirata TCA (2006); Hirata JP Conf Ser (2006) CI PT CC 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 Expansion CIS, CISD, CISDT, CISDTQ Hirata JPCA (2003) CIS+perturbation CIS(D), CIS(3), CIS(4) Hirata JCP (2005) Perturbation MP2, MP3, MP4 Hirata JPCA (2003) Excited State Theories EOM-CCSD EOM-CCSDT EOM-CCSDTQ Hirata JCP (2004) Ionization Theory IP-EOM-CCSD IP-EOM-CCSDT IP-EOM-CCSDTQ Kamiya & Hirata JCP (2006) Cluster Expansion CCD, CCSD, CCSDT, CCSDTQ, LCCD, LCCSD, QCISD Hirata JPCA (2003) Electron Attachment Theory EA-EOM-CCSD EA-EOM-CCSDT EA-EOM-CCSDTQ Kamiya & Hirata (2007) EOM-CC+perturbation EOM-CCSD(2) T, EOM-CCSD(2) TQ EOM-CCSD(3) T Shiozaki, Hirao & Hirata JCP (2007) Other CIS+2 nd order D-CIS(2), SCS-CIS(D) SOS-CIS(D) Fan & Hirata (2007)

6. CC-R12, EOM-CC-R12, Λ-CC-R12 Shiozaki, Kamiya, Hirata, & Valeev, in preparation (2008) Toru Shiozaki University of Florida New types of ansatz – new symbolic algabra code Significantly more complex equations Longer computational sequences Multiple hotspots Possibilities of various approximations

7. CC-R12 R12-CCSD on 100 processors ~ CCSD on 100,000 processors

8. Linear scaling CC Linear scaling CCSD on 1 processor ~ CCSD on 100,000 processors

9. Fast methods for water clusters Hirata et al. MP (2005) Pair energy in the presence of dipole field N-body (N > 2) Coulomb in dipole-dipole approximation 1 and 2-body Coulomb Exchange Correlation

10. Fast methods: excited states Hirata et al. MP (2005) A record EOM-CCSD aug-cc-pVDZ calculation for a 247- atom system Constant scaling!

11. 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.”

12.  1 and  2 type solid formic acid

13. Molecular crystals Ice XI Formamide Hydrogen fluoride