Towards PPCC So Hirata Quantum Theory Project University
- Slides: 13
Towards PPCC So Hirata Quantum Theory Project University of Florida Sanibel Symposium 2008, Parallel CC Workshop
Issues at petascale l l l 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 algebra Hirata, JPCA (2003); Hirata, TCA (2006); Hirata, JP Conf. Ser. (2006) Definition of a many-electron theory Mathematical expressions A parallel computer program
Automated symbolic algebra Hirata, JPCA (2003); Hirata, TCA (2006); Hirata, JP Conf. Ser. (2006) l l 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 Agent Smith “The Matrix”
Implemented methods Hirata JPCA (2003); Hirata TCA (2006); Hirata JP Conf Ser (2006) Electron Attachment Theory EA-EOM-CCSDTQ Linear Expansion CIS, CISDT, CISDTQ Hirata JPCA (2003) Kamiya & Hirata (2007) CIS+perturbation CIS(D), CIS(3), CIS(4) CI Ionization Theory IP-EOM-CCSDTQ Hirata JCP (2005) Other CIS+2 nd order D-CIS(2), SCS-CIS(D) SOS-CIS(D) Kamiya & Hirata JCP (2006) Excited State Theories EOM-CCSDTQ Hirata JCP (2004) Cluster Expansion CCD, CCSDT, CCSDTQ, LCCD, LCCSD, QCISD Hirata JPCA (2003) Fan & Hirata (2007) CC PT EOM-CC+perturbation EOM-CCSD(2)T, EOM-CCSD(2)TQ EOM-CCSD(3)T Shiozaki, Hirao & Hirata JCP (2007) Perturbation MP 2, MP 3, MP 4 Hirata JPCA (2003) 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)
CC-R 12, EOM-CC-R 12, Λ-CC-R 12 Shiozaki, 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
CC-R 12 -CCSD on 100 processors ~ CCSD on 100, 000 processors
Linear scaling CCSD on 1 processor ~ CCSD on 100, 000 processors
Fast methods for water clusters Hirata et al. MP (2005) N-body (N > 2) Coulomb in dipole-dipole approximation 1 and 2 -body Coulomb Exchange Correlation Pair energy in the presence of dipole field
Fast methods: excited states Hirata et al. MP (2005) A record EOM-CCSD aug-cc-p. VDZ calculation for a 247 atom system Constant scaling!
Coupled-cluster for solids l 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. ”
1 and 2 type solid formic acid
Molecular crystals Hydrogen fluoride Formamide Ice XI
