Explanipedia

PETSc/TAO Users Manual Revision 3.24 Open

S. Balay, Shrirang Abhyankar, Mark F. Adams, Joshua W. Brown, P. Brune , et al. · 2025

Variants of thick-restart Lanczos for the Bethe-Salpeter eigenvalue problem Open

Fernando Alvarruiz, Blanca Mellado-Pinto, José E. Román · 2025

The non-Hermitian Bethe-Salpeter eigenvalue problem is a structured eigenproblem, with real eigenvalues coming in pairs $\{λ,-λ\}$ where the corresponding pair of eigenvectors are closely related, and furthermore the left eigenvectors can …

A Conceptual Model-Based Application for the Treatment and Management of Data in Pediatric Oncology: The Neuroblastoma Use Case Open

Jesús Carreño-Bolufer, José E. Román, Sarah A. Andres, Daniel Gabriel Pons, Vicente Vidal , et al. · 2025

PETSc/TAO Users Manual Revision 3.22 Open

Satish Balay, Shrirang Abhyankar, Mark Raymond Adams, J. Dillon Brown, P. Brune , et al. · 2024

This manual describes the use of the Portable, Extensible Toolkit for Scientific Computation (PETSc) and the Toolkit for Advanced Optimization (TAO) for the numerical solution of partial differential equations (PDEs) and related problems o…

Improving performance of contour integral-based nonlinear eigensolvers with infinite GMRES Open

Yuqi Liu, José E. Román, Meiyue Shao · 2024

In this work, the infinite GMRES algorithm, recently proposed by Correnty et al., is employed in contour integral-based nonlinear eigensolvers, avoiding the computation of costly factorizations at each quadrature node to solve the linear s…

Correlated volumes for extended wavefunctions on a random-regular graph Open

M. Pino, José E. Román · 2023

We analyze the ergodic properties of a metallic wavefunction for the Anderson model in a disordered random-regular graph with branching number $k=2.$ A few q-moments $I_q$ associated with the zero energy eigenvector are numerically compute…

PETSc/TAO Users Manual (Rev. 3.20) Open

Satish Balay, Shrirang Abhyankar, Mark F. Adams, S. Benson, Jed Brown , et al. · 2023

This manual describes the use of the Portable, Extensible Toolkit for Scientific Computation (PETSc) and the Toolkit for Advanced Optimization (TAO) for the numerical solution of partial differential equations and related problems on high-…

Acoustic modal analysis with heat release fluctuations using nonlinear eigensolvers Open

Varun Hiremath, José E. Román · 2023

PETSc/TAO Users Manual (Rev. 3.19) Open

Satish Balay, Shrirang Abhyankar, Mark F. Adams, S. Benson, Jed Brown , et al. · 2023

This manual describes the use of the Portable, Extensible Toolkit for Scientific Computation (PETSc) and the Toolkit for Advanced Optimization (TAO) for the numerical solution of partial differential equations and related problems on high-…

Acoustic modal analysis with heat release fluctuations using nonlinear eigensolvers Open

Varun Hiremath, José E. Román · 2022

Closed combustion devices like gas turbines and rockets are prone to thermoacoustic instabilities. Design engineers in the industry need tools to accurately identify and remove instabilities early in the design cycle. Many different approa…

A parallel structured banded DC algorithm for symmetric eigenvalue problems Open

Shengguo Li, Xia Liao, Yutong Lu, José E. Román, Xiaoqiang Yue · 2022

Thick-restarted joint Lanczos bidiagonalization for the GSVD Open

Fernando Alvarruiz, Carmen Campos, José E. Román · 2022

The computation of the partial generalized singular value decomposition (GSVD) of large-scale matrix pairs can be approached by means of iterative methods based on expanding subspaces, particularly Krylov subspaces. We consider the joint L…

Not All Pulmonary Nodules in Smokers are Lung Cancer Open

Bhagwan Dass, Jared Phillips, Erin Jacobs, José E. Román · 2021

Diagnosis of pulmonary nodules requires an in-depth workup, including clinical evaluation, laboratory and pulmonary functions tests, and imaging, which helped to identify in this patient pulmonary rheumatoid arthritis, an important factor …

KSPHPDDM and PCHPDDM: Extending PETSc with advanced Krylov methods and robust multilevel overlapping Schwarz preconditioners Open

Pierre Jolivet, José E. Román, Stefano Zampini · 2021

A Parallel Direct Eigensolver for Sequences of Hermitian Eigenvalue\n Problems with No Tridiagonalization Open

Shengguo Li, Xinzhe Wu, José E. Román, Ziyang Yuan, Ruibo Wang , et al. · 2020

In this paper, a Parallel Direct Eigensolver for Sequences of Hermitian\nEigenvalue Problems with no tridiagonalization is proposed, denoted by\n\\texttt{PDESHEP}, and it combines direct methods with iterative methods.\n\\texttt{PDESHEP} f…

A Parallel Direct Eigensolver for Sequences of Hermitian Eigenvalue Problems with No Tridiagonalization Open

Shengguo Li, Xinzhe Wu, José E. Román, Ziyang Yuan, Lizhi Cheng · 2020

In this paper, a Parallel Direct Eigensolver for Sequences of Hermitian Eigenvalue Problems with no tridiagonalization is proposed, denoted by \texttt{PDESHEP}, and it combines direct methods with iterative methods. \texttt{PDESHEP} first …

An extension of the Cayley transform method for a parameterized generalized inverse eigenvalue problem Open

Zeynab Dalvand, Masoud Hajarian, José E. Román · 2020

Summary Since recent studies have shown that the Cayley transform method can be an effective iterative method for solving the inverse eigenvalue problem, in this work, we consider using an extension of it for solving a type of parameterize…

Non-linear eigenvalue problems with GetDP and SLEPc: Eigenmode computations of frequency-dispersive photonic open structures Open

Guillaume Demésy, André Nicolet, Boris Gralak, Christophe Geuzaine, Carmen Campos , et al. · 2020

ELSI — An open infrastructure for electronic structure solvers Open

Victor Wen‐zhe Yu, Carmen Campos, William Harbutt Dawson, Alberto Garcı́a, Ville Havu , et al. · 2020

Stellarator microinstabilities and turbulence at low magnetic shear Open

B. J. Faber, M. J. Pueschel, P. W. Terry, C. C. Hegna, José E. Román · 2018

Gyrokinetic simulations of drift waves in low-magnetic-shear stellarators reveal that simulation domains comprised of multiple turns can be required to properly resolve critical mode structures important in saturation dynamics. Marginally …

SIESTA‐SIPs: Massively parallel spectrum‐slicing eigensolver for an <i>ab initio</i> molecular dynamics package Open

Murat Keçeli, Fabiano Corsetti, Carmen Campos, José E. Román, Hong Zhang , et al. · 2018

Integration of Shift‐and‐Invert Parallel Spectral Transformation (SIPs) eigensolver (as implemented in the SLEPc library) into an ab initio molecular dynamics package, SIESTA, is described. The effectiveness of the code is demonstrated on …

Widely-tunable, narrow-linewidth III-V/silicon hybrid external-cavity laser for coherent communication Open

Hang Guan, Ari Novack, Tal Galfsky, Yangjin Ma, Saeed Fathololoumi , et al. · 2018

We demonstrate a III-V/silicon hybrid external cavity laser with a tuning range larger than 60 nm at the C-band on a silicon-on-insulator platform. A III-V semiconductor gain chip is hybridized into the silicon chip by edge-coupling the si…

Eigenmode computations of frequency-dispersive photonic open structures: A non-linear eigenvalue problem Open

Guillaume Demésy, André Nicolet, Boris Gralak, Christophe Geuzaine, Carmen Campos , et al. · 2018

In this paper, we propose and compare different ways to address the numerical computation of the electromagnetic modes of frequency-dispersive scattering structures. A classical finite element formulation is derived for each proposed solut…

Compact and low loss 90° optical hybrid on a silicon-on-insulator platform Open

Hang Guan, Yangjin Ma, Ruizhi Shi, Xiaoliang Zhu, Rick Younce , et al. · 2017

We present a compact and low loss 90° optical hybrid on a silicon-on-insulator (SOI) platform for coherent receiving systems. Our 90° optical hybrid uses a novel topology, comprising one Y-junction and three 2x2 multimode interference (MMI…

firedrakeproject/petsc: Portable, Extensible Toolkit for Scientific Computation Open

Barry Smith, Satish Balay, Matthew G. Knepley, Jed Brown, Hong Zhang , et al. · 2017

Version of Firedrake used in 'The geometry of optimally transported meshes on the sphere'. This release is specifically created to document the version of Firedrake used in a particular set of experiments. Please do not cite this as a gene…

Multigroup neutron diffusion equation with the finite volume method in reactors using MOX fuels Open

Álvaro Bernal, José E. Román, R. Miró, G. Verdú · 2017

[EN] The use of mixed oxide (MOX) fuel to partially fill the cores of commercial light water reactors (LWRs) gives rise to a reduction of the radioactive waste and production of more energy. However, the use of MOX fuels in LWRs changes th…

Design and implementation of Java bindings in Open MPI Open

Oscar Vega-Gisbert, José E. Román, Jeffrey M. Squyres · 2016

Assembly Discontinuity Factors for the Neutron Diffusion Equation discretized with the Finite Volume Method. Application to BWR Open

Álvaro Bernal, José E. Román, R. Miró, G. Verdú · 2016

Parallel iterative refinement in polynomial eigenvalue problems Open

Carmen Campos, José E. Román · 2016

Summary Methods for the polynomial eigenvalue problem sometimes need to be followed by an iterative refinement process to improve the accuracy of the computed solutions. This can be accomplished by means of a Newton iteration tailored to m…

On low-frequency variability of the midlatitude ocean gyres Open

Igor Shevchenko, Pavel Berloff, David Guerrero-Lopez, José E. Román · 2016

This paper studies the large-scale low-frequency variability of the wind-driven midlatitude ocean gyres and their western boundary currents, such as the Gulf Stream or Kuroshio, simulated with the eddy-resolving quasi-geostrophic model. We…

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