Components for integral evaluation in quantum chemistry

Abstract

Sharing low-level functionality between software packages enables more rapid development of new capabilities and reduces the duplication of work among development groups. Using the component approach advocated by the Common Component Architecture Forum, we have designed a flexible interface for sharing integrals between quantum chemistry codes. Implementation of these interfaces has been undertaken within the Massively Parallel Quantum Chemistry package, exposing both the IntV3 and Cints/Libint integrals packages to component applications. Benchmark timings for Hartree-Fock calculations demonstrate that the overhead due to the added interface code varies significantly, from less than 1% for small molecules with large basis sets to nearly 10% for larger molecules with smaller basis sets. Correlated calculations and density functional approaches encounter less severe performance overheads of less than 5%. While these overheads are acceptable, additional performance losses occur when arbitrary implementation details, such as integral ordering within buffers, must be handled. Integral reordering is observed to add an additional overhead as large as 12%; hence, a common standard for such implementation details is desired for optimal performance.

Fast native function calls for the Babel language interoperability framework

“…Instead, they are sometimes mainly interested in clean interface specifications, remote method invocation, or the object oriented programming model provided on top of traditional procedural languages such as Fortran. For these users, even a moderate overhead is often reason enough (a) not to adopt Babel at all or (b) design applications with these performance considerations in mind, often leading to less intuitive interfaces [24]. Thus, the primary motivation of this work is to reduce the Babel overhead for these users, thereby facilitating adoption and impacting a larger audience.…”

“…The domains in which Babel is used are widespread and range from applications in chemistry, astronomy, and biology to mathematical solvers, programming models, and performance monitoring tools. Established users of the Babel language interoperability middleware and/or the CCA as a whole include the hypre preconditioner library [5], the ComPASS project [2], the CSDMS project [1], the FACETS project [4], and the MPQC quantum chemistry package [22], [24], [21].…”

Development of high performance scientific components for interoperability of computing packages

“…Component-based development allows reuse of existing components without knowing its internal details as long as the component complies with the set of interfaces [22]. [25].…”

The Component-Based Application for GAMESS

“…Following a class hierarchy very similar to the CCA integral interfaces [24], the integral packages are encapsulated by integral evaluator and integral factory interfaces described within the MPQC documentation [25]. This encapsulation insures a clean separation of the integrals code which greatly simplified packaging the integral packages within MPQC as stand-alone components.…”

“…The AtomicInterface provides the shell data for an atomic Gaussian basis set (AO), which provides a Gaussian shell for any given shell number. The ShellInterface provides the primitive and contraction data for a Gaussian shell [24]. Through these interfaces, the information required for computing integrals can be passed from one package to another package without initializing every package.…”