34 citations · 91 across the 12 of their papers we have counts for
12 papers
Contour Integral-based Quantum Algorithm for Estimating Matrix Eigenvalue Density
Yasunori Futamura, Xiucai Ye, Tetsuya Sakurai
The eigenvalue density of a matrix plays an important role in various types of scientific computing such as electronic-structure calculations. In this paper, we propose a quantum a…
Unsupervised learning-based structural analysis: Search for a characteristic low-dimensional space by local structures in atomistic simulations
Ryo Tamura, Momo Matsuda, Jianbo Lin +3
Owing to the advances in computational techniques and the increase in computational power, atomistic simulations of materials can simulate large systems with higher accuracy. Compl…
Flexible subspace iteration with moments for an effective contour integration-based eigensolver
Sarah Huber, Yasunori Futamura, Martin Galgon +3
Contour integration schemes are a valuable tool for the solution of difficult interior eigenvalue problems. However, the solution of many large linear systems with multiple right h…
Benefits from using mixed precision computations in the ELPA-AEO and ESSEX-II eigensolver projects
Andreas Alvermann, Achim Basermann, Hans-Joachim Bungartz +30
We first briefly report on the status and recent achievements of the ELPA-AEO (Eigenvalue Solvers for Petaflop Applications - Algorithmic Extensions and Optimizations) and ESSEX II…
Efficient and Scalable Calculation of Complex Band Structure using Sakurai-Sugiura Method
Shigeru Iwase, Yasunori Futamura, Akira Imakura +2
Complex band structures (CBSs) are useful to characterize the static and dynamical electronic properties of materials. Despite the intensive developments, the first-principles calc…
Contour integral method for obtaining the self-energy matrices of electrodes in electron transport calculations
Shigeru Iwase, Yasunori Futamura, Akira Imakura +3
We propose an efficient computational method for evaluating the self-energy matrices of electrodes to study ballistic electron transport properties in nanoscale systems. To reduce…
Efficient calculation of electronic structure using O(N) density functional theory
Ayako Nakata, Yasunori Futamura, Tetsuya Sakurai +2
We propose an efficient way to calculate the electronic structure of large systems by combining a large-scale first-principles density functional theory code, Conquest, and an effi…
Reduced-Shifted Conjugate-Gradient Method for a Green's Function: Efficient Numerical Approach in a Nano-structured Superconductor
Yuki Nagai, Yasushi Shinohara, Yasunori Futamura +1
We propose the reduced-shifted Conjugate-Gradient (RSCG) method, which is numerically efficient to calculate a matrix element of a Green's function defined as a resolvent of a Hami…
Alternating optimization method based on nonnegative matrix factorizations for deep neural networks
Tetsuya Sakurai, Akira Imakura, Yuto Inoue +1
The backpropagation algorithm for calculating gradients has been widely used in computation of weights for deep neural networks (DNNs). This method requires derivatives of objectiv…
Stochastic Estimation of Nuclear Level Density in the Nuclear Shell Model: An Application to Parity-Dependent Level Density in Ni
Noritaka Shimizu, Yutaka Utsuno, Yasunori Futamura +3
We introduce a novel method to obtain level densities in large-scale shell-model calculations. Our method is a stochastic estimation of eigenvalue count based on a shifted Krylov-s…
A filtering technique for the temporally reduced matrix of the Wilson fermion determinant
Yasunori Futamura, Shoji Hashimoto, Akira Imakura +2
The Wilson fermion determinant can be written in the form of a series expansion in fugacity , provided that the eigenmodes of the temporally reduced operator are obtai…
Numerical construction of a low-energy effective Hamiltonian in a self-consistent Bogoliubov-de Gennes approach of superconductivity
Yuki Nagai, Yasushi Shinohara, Yasunori Futamura +2
We propose a fast and efficient approach for solving the Bogoliubov-de Gennes (BdG) equations in superconductivity, with a numerical matrix-size reduction procedure proposed by Sak…