scholarly journals Thick-restart block Lanczos method for large-scale shell-model calculations

2019 ◽  
Vol 244 ◽  
pp. 372-384 ◽  
Author(s):  
Noritaka Shimizu ◽  
Takahiro Mizusaki ◽  
Yutaka Utsuno ◽  
Yusuke Tsunoda
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Lanczos Method ◽  
Model Calculations ◽  
Block Lanczos ◽  
Block Lanczos Method

An Out-of-Core Eigen-Solver with OpenMP Parallel Scheme for Large Spare Damped System

2019 ◽  
Vol 16 (07) ◽  
pp. 1950038 ◽  
Author(s):  
S. H. Ju ◽  
H. H. Hsu
Keyword(s):  
Large Scale ◽  
Block Size ◽  
Lanczos Method ◽  
Preconditioned Conjugate Gradient ◽  
Damped System ◽  
Parallel Scheme ◽  
Complex Eigenvalues ◽  
Lanczos Iteration ◽  
Block Lanczos ◽  
Block Lanczos Method

An out-of-core block Lanczos method with the OpenMP parallel scheme was developed to solve large spare damped eigenproblems. The symmetric generalized eigenproblem is first solved using the block Lanczos method with the preconditioned conjugate gradient (PCG) method, and the condensed damped eigenproblem is then solved to obtain the complex eigenvalues. Since the PCG solvers and out-of-core schemes are used, a large-scale eigenproblem can be solved using minimal computer memory. The out-of-core arrays only need to be read once in each Lanczos iteration, so the proposed method requires little extra CPU time. In addition, the second-level OpenMP parallel computation in the PCG solver is suggested to avoid using a large block size that often increases the number of iterations needed to achieve convergence.

scholarly journals Study of nuclei around Z = 28 by large-scale shell model calculations

2013 ◽  
Vol 445 ◽  
pp. 012028 ◽  
Author(s):  
Y Tsunoda ◽  
T Otsuka ◽  
N Shimizu ◽  
M Honma ◽  
Y Utsuno
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Model Calculations

scholarly journals Large Scale Shell Model Calculations of the Negative-Parity States Structure in 24Mg Nucleus

2021 ◽  
Vol 66 (4) ◽  
pp. 293
Author(s):  
A.A. Al-Sammarraie ◽  
F.A. Ahmed ◽  
A.A. Okhunov
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Transition Probabilities ◽  
Transition Probability ◽  
Energy Levels ◽  
Form Factors ◽  
Model Space ◽  
Negative Parity ◽  
Matrix Elements ◽  
Model Calculations

The negative-parity states of 24Mg nucleus are investigated within the shell model. We are based on the calculations of energy levels, total squared form factors, and transition probability using the p-sd-pf (PSDPF) Hamiltonian in a large model space (0 + 1) hW. The comparison between the experimental and theoretical states showed a good agreement within a truncated model space. The PSDPF-based calculations successfully reproduced the data on the total squared form factors and transition probabilities of the negative-parity states in 24Mg nucleus. These quantities depend on the one-body density matrix elements that are obtained from the PSDPF Hamiltonian. The wave functions of radial one-particle matrix elements calculated with the harmonic-oscillator potential are suitable to predict experimental data by changing the center-of-mass corrections.

A Block Lanczos Method for the CDT Subproblem

2019 ◽  
Vol 37 (2) ◽  
pp. 240-260
Author(s):  
Liqiang Song and Weihong Yang
Keyword(s):  
Lanczos Method ◽  
Block Lanczos ◽  
Block Lanczos Method
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