@article {,
	title = {Direct Determination of Optimal Real-Space Orbitals for Correlated Electronic Structure of Molecules},
	journal = {Journal of Chemical Theory and Computation},
	volume = {19},
	year = {2023},
	month = {2023-10},
	pages = {7230 - 7241},
	abstract = {We demonstrate how to determine numerically nearly exact orthonormal orbitals that are optimal for the evaluation of the energy of arbitrary (correlated) states of atoms and molecules by minimization of the energy Lagrangian. Orbitals are expressed in real space using a multiresolution spectral element basis that is refined adaptively to achieve the user-specified target precision while avoiding the ill-conditioning issues that plague AO basis set expansions traditionally used for correlated models of molecular electronic structure. For light atoms, the orbital solver, in conjunction with a variational electronic structure model [selected Configuration Interaction (CI)] provides energies of comparable precision to a state-of-the-art atomic CI solver. The computed electronic energies of atoms and molecules are significantly more accurate than the counterparts obtained with the orbital sets of the same rank expanded in Gaussian AO bases, and can be determined even when linear dependence issues preclude the use of the AO bases. It is feasible to optimize more than 100 fully correlated numerical orbitals on a single computer node, and significant room exists for additional improvement. These findings suggest that real-space orbital representations might be the preferred alternative to AO representations for high-end models of correlated electronic states of molecules and materials.},
	issn = {1549-9618},
	doi = {10.1021/acs.jctc.3c00732},
	url = {https://pubs.acs.org/doi/10.1021/acs.jctc.3c00732},
	author = {Valeev, Edward F. and Harrison, Robert J. and Holmes, Adam A. and Peterson, Charles C. and Penchoff, Deborah A.}
}
@conference {,
	title = {Composition of Algorithmic Building Blocks in Template Task Graphs},
	booktitle = {2022 IEEE/ACM Parallel Applications Workshop: Alternatives To MPI+X (PAW-ATM)},
	year = {2022},
	month = {2023-01},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Dallas, TX, USA},
	doi = {10.1109/PAW-ATM56565.2022.00008},
	url = {https://ieeexplore.ieee.org/document/10024647/},
	author = {Herault, Thomas and Schuchart, Joseph and Valeev, Edward F. and George Bosilca}
}
@article {,
	title = {Evaluations of molecular modeling and machine learning for predictive capabilities in binding of lanthanum and actinium with carboxylic acids},
	journal = {Journal of Radioanalytical and Nuclear Chemistry},
	year = {2022},
	month = {2022-12},
	issn = {0236-5731},
	doi = {10.1007/s10967-022-08620-7},
	url = {https://rdcu.be/c2lGj},
	author = {Penchoff, Deborah A. and Peterson, Charles C. and Wrancher, Eleigha M. and George Bosilca and Harrison, Robert J. and Valeev, Edward F. and Benny, Paul D.}
}
@conference {,
	title = {Generalized Flow-Graph Programming Using Template Task-Graphs: Initial Implementation and Assessment},
	booktitle = {2022 IEEE International Parallel and Distributed Processing Symposium (IPDPS)},
	year = {2022},
	month = {2022-07},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Lyon, France},
	abstract = {We present and evaluate TTG, a novel programming model and its C++ implementation that by marrying the ideas of control and data flowgraph programming supports compact specification and efficient distributed execution of dynamic and irregular applications. Programming interfaces that support task-based execution often only support shared memory parallel environments; a few support distributed memory environments, either by discovering the entire DAG of tasks on all processes, or by introducing explicit communications. The first approach limits scalability, while the second increases the complexity of programming. We demonstrate how TTG can address these issues without sacrificing scalability or programmability by providing higher-level abstractions than conventionally provided by task-centric programming systems, without impeding the ability of these runtimes to manage task creation and execution as well as data and resource management efficiently. TTG supports distributed memory execution over 2 different task runtimes, PaRSEC and MADNESS. Performance of four paradigmatic applications (in graph analytics, dense and block-sparse linear algebra, and numerical integrodifferential calculus) with various degrees of irregularity implemented in TTG is illustrated on large distributed-memory platforms and compared to the state-of-the-art implementations.},
	doi = {10.1109/IPDPS53621.2022.00086},
	url = {https://ieeexplore.ieee.org/abstract/document/9820613},
	author = {Schuchart, Joseph and Nookala, Poornima and Javanmard, Mohammad Mahdi and Herault, Thomas and Valeev, Edward F. and George Bosilca and Harrison, Robert J.}
}
@conference {,
	title = {Pushing the Boundaries of Small Tasks: Scalable Low-Overhead Data-Flow Programming in TTG},
	booktitle = {2022 IEEE International Conference on Cluster Computing (CLUSTER)},
	year = {2022},
	month = {2022-09},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Heidelberg, Germany},
	abstract = {Shared memory parallel programming models strive to provide low-overhead execution environments. Task-based programming models, in particular, are well-suited to cope with the ubiquitous multi- and many-core systems since they allow applications to express all available concurrency to a scheduler, which is tasked with exploiting the available hardware resources. It is general consensus that atomic operations should be preferred over locks and mutexes to avoid inter-thread serialization and the resulting loss in efficiency. However, even atomic operations may serialize threads if not used judiciously. In this work, we will discuss several optimizations applied to TTG and the underlying PaRSEC runtime system aiming at removing contentious atomic operations to reduce the overhead of task management to a few hundred clock cycles. The result is an optimized data-flow programming system that seamlessly scales from a single node to distributed execution and which is able to compete with OpenMP in shared memory.},
	keywords = {Dataflow graph, Hardware, Instruction sets, Memory management, PaR-SEC, parallel programming, runtime, scalability, Task analysis, task-based programming, Template Task Graph, TTG},
	doi = {10.1109/CLUSTER51413.2022.00026},
	url = {https://ieeexplore.ieee.org/document/9912704/},
	author = {Schuchart, Joseph and Nookala, Poornima and Herault, Thomas and Valeev, Edward F. and George Bosilca}
}
