Numerical Challenges in a Cholesky‐Decomposed Local Correlation Quantum Chemistry Framework

Krisiloff, David B.; Dieterich, Johannes M.; Libisch, Florian; Carter, Emily A.

doi:10.1002/9781118853887.ch3

Cited by 14 publications

(36 citation statements)

References 40 publications

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“…TigerCI currently is a plugin to either MOLCAS [21] or GAMESS [22][23][24]. As both the algorithms and numerical challenges have been reviewed at length elsewhere [2,8], we focus here on concise discussions of the properties relevant for our integral-direct implementation.…”

Section: Algorithmsmentioning

confidence: 99%

“…All algorithms presented in this contribution were implemented in our TigerCI program for Cholesky-decomposed (CD) local multi-reference SDCI/ACPF [2,7,8,13,14,[18][19][20]. TigerCI currently is a plugin to either MOLCAS [21] or GAMESS [22][23][24].…”

Section: Algorithmsmentioning

confidence: 99%

“…In this contribution, we discuss our new integral-direct, parallel [6] implementation of Cholesky-decomposed local multi-reference singles and doubles configuration interaction (CD-LMRSDCI [7]) and its size-extensive extension, multi-reference averaged coupled-pair functional (MRACPF) [8] theory within our TigerCI code [2]. Since I/O is intrinsically a process of low parallelism, fewer I/O operations directly translate to reducing bottlenecks in the code.…”

Section: Introductionmentioning

confidence: 99%

“…Local correlation methods typically employ integral-direct implementations because keeping track of only the relevant integrals proves cumbersome [2][3][4]. Others have shown that a rigorous prescreening of the integrals can be used to reduce the scaling of, e.g., Møller-Plesset perturbation theory [5].…”

Section: Introductionmentioning

confidence: 99%

“…Instead, depending on the number of integrals of a certain type and access character, the integrals are either recomputed or stored on disk with optional buffering provided by our IOBuffer [2]. We will discuss the reasons for integral-direct reformulations of various different types of kernels in what follows.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Assessment of a semi integral-direct local multi-reference configuration interaction implementation employing shared-memory parallelization

Dieterich

Carter

2015

Computational and Theoretical Chemistry

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Section: Algorithmsmentioning

confidence: 99%

Section: Algorithmsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Assessment of a semi integral-direct local multi-reference configuration interaction implementation employing shared-memory parallelization

Dieterich

Carter

2015

Computational and Theoretical Chemistry

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Multireference Approaches for Excited States of Molecules

et al. 2018

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Understanding the properties of electronically excited states is a challenging task that becomes increasingly important for numerous applications in chemistry, molecular physics, molecular biology, and materials science. A substantial impact is exerted by the fascinating progress in time-resolved spectroscopy, which leads to a strongly growing demand for theoretical methods to describe the characteristic features of excited states accurately. Whereas for electronic ground state problems of stable molecules the quantum chemical methodology is now so well developed that informed nonexperts can use it efficiently, the situation is entirely different concerning the investigation of excited states. This review is devoted to a specific class of approaches, usually denoted as multireference (MR) methods, the generality of which is needed for solving many spectroscopic or photodynamical problems. However, the understanding and proper application of these MR methods is often found to be difficult due to their complexity and their computational cost. The purpose of this review is to provide an overview of the most important facts about the different theoretical approaches available and to present by means of a collection of characteristic examples useful information, which can guide the reader in performing their own applications.

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Projector-Free Capped-Fragment Scheme within Density Functional Embedding Theory for Covalent and Ionic Compounds

Martirez

Carter

2021

J. Chem. Theory Comput.

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Quantum-mechanics-(QM)-based simulations now routinely aid in understanding and even discovering new chemistries involving molecules and materials exhibiting desired functionalities. Ab initio correlated wavefunction (CW) theories systematically improve QM methods, with many exhibiting high accuracy. However, execution of CW methods requires expensive computations that typically scale poorly with system size. Divideand-conquer approaches partition large systems into smaller fragments; a lower level of theory treats fragment interactions while a preferred higher level of theory describes the important fragment. These methods offer ways to incorporate CWs into chemical simulations of large systems, e.g., biomolecules, surfaces, large inorganic clusters, bulk crystals, etc. Here we propose a partitioning protocol that utilizes capping atoms to saturate severed covalent bonds at fragment interfaces and density functional embedding theory (DFET) to describe fragment interactions. The capping groups in each fragment provide an ad-hoc potential that approximates the effects of the environment. An embedding potential optimized via DFET then serves as an augmentation of the capping group to simulate the effects of the environment. We concurrently use an auxiliary fragment (a separate system comprised of only the combined capping groups) to account for, and thereby correct, the electron density contributions of all the capping groups added to all of the fragments. This method depends only on the capped-subsystem and auxiliary-fragment electron densities, forgoing, as with the original DFET developed for metallic systems, orbital-based projector approaches that determine a nonlocal action of the embedding potential onto the fragment electrons. By using an auxiliary fragment, the method maintains a purely electron-density-dependent embedding potential, substantially lessening the cost and leading to simpler implementation. Here, we demonstrate the utility of our capped-DFET and ensuing capped embedded CW method in two contrasting systems, namely, an organic molecule and an ionic metal oxide cluster.

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Numerical Challenges in a Cholesky‐Decomposed Local Correlation Quantum Chemistry Framework

Cited by 14 publications

References 40 publications

Assessment of a semi integral-direct local multi-reference configuration interaction implementation employing shared-memory parallelization

Assessment of a semi integral-direct local multi-reference configuration interaction implementation employing shared-memory parallelization

Multireference Approaches for Excited States of Molecules

Projector-Free Capped-Fragment Scheme within Density Functional Embedding Theory for Covalent and Ionic Compounds

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