MPQC: Massively Parallel Quantum Chemistry

Scaling of the MP2-R12/A' energy computation on benzene molecule using several popular interconnects. Scaling on a low-latency interconnect such as Infiniband is very good.
MPQC is a unique electronic structure package. It is highly scalable (has been run on thousands of processors), its design is heavily object-oriented and implemented in C++, and it is freely available, including its source (stable releases and anonymous CVS repository). Our group has contributed the explicitly correlated MP2 code and integral factories to interface to Libint.
- Learn more and download MPQC source code from www.mpqc.org.
- Spring 2006 MPQC Workshop was held in Atlanta, GA (see discussion minutes).
Libint

Schematic description ofhow the Libint compiler works. Recurrence relations and heuristics are given as input. Recurrence relations are applied to the target integrals, computation graph is generated and optimized using the heuristic info, and then translated to produce the output: the library source code.
Libint is a open-source library for efficient evaluation of several kinds of two-body molecular integrals over Gaussian functions. The library source is generated by Libint compiler and therefore can be highly optimized (for example, code can be taylored for execution on vector processors). The notable feature is the support for the standard electron repulsion integrals as well as the integrals for explicitly correlated R12 methods.
- Learn more and download library source code from Libint website.
- Presentation on Libint version 2 from the second annual NLCF Computational Chemistry Workshop held at Oak Ridge National Laboratory in August 2005.
PSI3
PSI3 is an electronic structure package which emphasizes highly accurate wave function methods, such as coupled cluster and configuration interaction. It is written in C and freely available, including its source code. Prof. Valeev has contributed many components to the package, including the input program, the one-electron properties code, the integrals code, the MP2-R12 code, and the Diagonal Born-Oppenheimer Correction code.
- Learn more and download PSI3 source code from www.psicode.org.
Misc
Other software developed in this group may not qualify for production-level status.
- SeQuant is a Mathematica package for handling second-quantized expressions using Wick's theorem.

