46,362 research outputs found

    Tackling component interoperability in quantum chemistry software

    Get PDF
    The Common Component Architecture (CCA) offers an environment that allows scientific packages to dynamically interact with each other through components. Conceptually, a computation can be constructed with plugand- play components from any componentized scientific package; however, providing such plug-and-play components from scientific packages requires more than componentizing functions/subroutines of interest, especially for large-scale scientific packages with a long development history. In this paper, we present our efforts to construct components for the integral evaluation - a fundamental sub-problem of quantum chemistry computations - that conform to the CCA specification. The goal is to enable fine-grained interoperability between three quantum chemistry packages, GAMESS, NWChem, and MPQC, via CCA integral components. The structures of these packages are quite different and require different approaches to construct and exploit CCA components. We focus on one of the three packages, GAMESS, delineating the structure of the integral computation in GAMESS, followed by our approaches to its component development. Then we use GAMESS as the driver to interoperate with integral components from another package, MPQC, and discuss the possible solutions for interoperability problems along with preliminary results

    Lowering of the complexity of quantum chemistry methods by choice of representation

    Get PDF
    The complexity of the standard hierarchy of quantum chemistry methods is not invariant to the choice of representation. This work explores how the scaling of common quantum chemistry methods can be reduced using real-space, momentum-space, and time-dependent intermediate representations without introducing approximations. We find the scalings of exact Gaussian basis Hartree--Fock theory, second-order M{\o}ller-Plesset perturbation theory, and coupled cluster theory (specifically, linearized coupled cluster doubles and the distinguishable cluster approximation with doubles) to be O(N3)\mathcal{O}(N^3), O(N3)\mathcal{O}(N^3), and O(N5)\mathcal{O}(N^5) respectively, where NN denotes system size. These scalings are not asymptotic and hold over all ranges of NN

    Towards quantum-chemical method development for arbitrary basis functions

    Full text link
    We present the design of a flexible quantum-chemical method development framework, which supports employing any type of basis function. This design has been implemented in the light-weight program package molsturm, yielding a basis-function-independent self-consistent field scheme. Versatile interfaces, making use of open standards like python, mediate the integration of molsturm with existing third-party packages. In this way both rapid extension of the present set of methods for electronic structure calculations as well as adding new basis function types can be readily achieved. This makes molsturm well-suitable for testing novel approaches for discretising the electronic wave function and allows comparing them to existing methods using the same software stack. This is illustrated by two examples, an implementation of coupled-cluster doubles as well as a gradient-free geometry optimisation, where in both cases, an arbitrary basis functions could be used. molsturm is open-source and can be obtained from https://molsturm.org.Comment: 15 pages and 7 figure
    corecore