FELIX2.0: New version of the finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation
The timedependent generator coordinate method (TDGCM) is a powerful method to study the large amplitude collective motion of quantum manybody systems such as atomic nuclei. Under the Gaussian Overlap Approximation (GOA), the TDGCM leads to a local, timedependent Schrödinger equation in a multidimensional collective space. In this study, we present the version 2.0 of the code FELIX that solves the collective Schrödinger equation in a finite element basis. This new version features: (i) the ability to solve a generalized TDGCM+GOA equation with a metric term in the collective Hamiltonian, (ii) support for new kinds of finite elements and different types of quadrature to compute the discretized Hamiltonian and overlap matrices, (iii) the possibility to leverage the spectral element scheme, (iv) an explicit Krylov approximation of the time propagator for time integration instead of the implicit Crank–Nicolson method implemented in the first version, (v) an entirely redesigned workflow. We benchmark this release on an analytic problem as well as on realistic twodimensional calculations of the lowenergy fission of ^{240}Pu and ^{256}Fm. Low to moderate numerical precision calculations are most efficiently performed with simplex elements with a degree 2 polynomial basis. Higher precision calculations should instead use the spectral element method withmore »
 Authors:

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^{[3]}
 Univ. ParisSud, Orsay (France). Inst. of Nuclear Physics. IN2P3CNRS
 Alternative Energies and Atomic Energy Commission (CEA), Arpajon (France)
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Nuclear and Chemical Science Division
 Publication Date:
 Report Number(s):
 LLNLJRNL735217
Journal ID: ISSN 00104655
 Grant/Contract Number:
 AC5207NA27344; AC0500OR22725; AC0205CH11231
 Type:
 Accepted Manuscript
 Journal Name:
 Computer Physics Communications
 Additional Journal Information:
 Journal Volume: 225; Journal ID: ISSN 00104655
 Publisher:
 Elsevier
 Research Org:
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. ParisSud, Orsay (France)
 Sponsoring Org:
 USDOE Office of Science (SC)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 97 MATHEMATICS AND COMPUTING; FELIX; finite element; spectral element; generator coordinate method; Gaussian overlap approximation; nuclear fission
 OSTI Identifier:
 1438682
Regnier, D., Dubray, N., Verriere, M., and Schunck, N.. FELIX2.0: New version of the finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation. United States: N. p.,
Web. doi:10.1016/j.cpc.2017.12.007.
Regnier, D., Dubray, N., Verriere, M., & Schunck, N.. FELIX2.0: New version of the finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation. United States. doi:10.1016/j.cpc.2017.12.007.
Regnier, D., Dubray, N., Verriere, M., and Schunck, N.. 2017.
"FELIX2.0: New version of the finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation". United States.
doi:10.1016/j.cpc.2017.12.007. https://www.osti.gov/servlets/purl/1438682.
@article{osti_1438682,
title = {FELIX2.0: New version of the finite element solver for the time dependent generator coordinate method with the Gaussian overlap approximation},
author = {Regnier, D. and Dubray, N. and Verriere, M. and Schunck, N.},
abstractNote = {The timedependent generator coordinate method (TDGCM) is a powerful method to study the large amplitude collective motion of quantum manybody systems such as atomic nuclei. Under the Gaussian Overlap Approximation (GOA), the TDGCM leads to a local, timedependent Schrödinger equation in a multidimensional collective space. In this study, we present the version 2.0 of the code FELIX that solves the collective Schrödinger equation in a finite element basis. This new version features: (i) the ability to solve a generalized TDGCM+GOA equation with a metric term in the collective Hamiltonian, (ii) support for new kinds of finite elements and different types of quadrature to compute the discretized Hamiltonian and overlap matrices, (iii) the possibility to leverage the spectral element scheme, (iv) an explicit Krylov approximation of the time propagator for time integration instead of the implicit Crank–Nicolson method implemented in the first version, (v) an entirely redesigned workflow. We benchmark this release on an analytic problem as well as on realistic twodimensional calculations of the lowenergy fission of 240Pu and 256Fm. Low to moderate numerical precision calculations are most efficiently performed with simplex elements with a degree 2 polynomial basis. Higher precision calculations should instead use the spectral element method with a degree 4 polynomial basis. Finally, we emphasize that in a realistic calculation of fission mass distributions of 240Pu, FELIX2.0 is about 20 times faster than its previous release (within a numerical precision of a few percents).},
doi = {10.1016/j.cpc.2017.12.007},
journal = {Computer Physics Communications},
number = ,
volume = 225,
place = {United States},
year = {2017},
month = {12}
}