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Fast semistochastic heat-bath configuration interaction

TLDR
In this article, a fast semistochastic heat-bath configuration interaction (SHCI) method for solving the many-body Schrodinger equation is presented, which identifies and eliminates computational bottlenecks in both the variational and perturbative steps.
Abstract
This paper presents in detail our fast semistochastic heat-bath configuration interaction (SHCI) method for solving the many-body Schrodinger equation. We identify and eliminate computational bottlenecks in both the variational and perturbative steps of the SHCI algorithm. We also describe the parallelization and the key data structures in our implementation, such as the distributed hash table. The improved SHCI algorithm enables us to include in our variational wavefunction two orders of magnitude more determinants than has been reported previously with other selected configuration interaction methods. We use our algorithm to calculate an accurate benchmark energy for the chromium dimer with the X2C relativistic Hamiltonian in the cc-pVDZ-DK basis, correlating 28 electrons in 76 spatial orbitals. Our largest calculation uses two billion Slater determinants in the variational space and semistochastically includes perturbative contributions from at least trillions of additional determinants with better than 10-5 Ha statistical uncertainty.

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Recent developments in the PySCF program package

TL;DR: PySCF as mentioned in this paper is a Python-based general-purpose electronic structure platform that supports first-principles simulations of molecules and solids as well as accelerates the development of new methodology and complex computational workflows.
Journal ArticleDOI

The density matrix renormalization group in chemistry and molecular physics: Recent developments and new challenges

TL;DR: In this paper, the authors discuss the major features of DMRG, highlighting its strengths and weaknesses also in comparison with other novel approaches, and discuss possible routes to recover dynamical correlation.
References
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Journal ArticleDOI

A fifth-order perturbation comparison of electron correlation theories

TL;DR: In this paper, a new augmented version of coupled-cluster theory, denoted as CCSD(T), is proposed to remedy some of the deficiencies of previous augmented coupledcluster models.
Journal ArticleDOI

Density-matrix algorithms for quantum renormalization groups.

TL;DR: A formulation of numerical real-space renormalization groups for quantum many-body problems is presented and several algorithms utilizing this formulation are outlined, which can be applied to almost any one-dimensional quantum lattice system, and can provide a wide variety of static properties.
Journal ArticleDOI

The density-matrix renormalization group

TL;DR: The density-matrix renormalization group (DMRG) as mentioned in this paper is a numerical algorithm for the efficient truncation of the Hilbert space of low-dimensional strongly correlated quantum systems based on a rather general decimation prescription.
Journal ArticleDOI

Nobel Lecture: Electronic structure of matter-wave functions and density functionals

TL;DR: In this article, an alternative approach to the theory of electronic struc- ture, in which the electron density distribution n(r), rather than the many-electron wave function, plays a central role, is presented.
Journal ArticleDOI

Individualized configuration selection in CI calculations with subsequent energy extrapolation

TL;DR: In this paper, a configuration selection method for CI calculations is discussed and applied in which the energy lowering produced in a secular equation by the addition of a given test species to a series of dominant configurations is used as an ordering parameter.
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