Parallel block preconditioning based on SSOR and MILU. - Takumi Washio; Ken Hayami (Numer. Linear Algebra Appl., 1994)

Overlapped Multicolor MILU Preconditioning. - Takumi Washio; Ken Hayami (SIAM J. Sci. Comput., 1995)

Extrapolation method of iterated collocation solution for two-dimensional nonlinear Volterra integral equations. - Guoqiang Han; Ken Hayami; Kokichi Sugihara; Wang Jiong (Appl. Math. Comput., 2000)

Product integration method for Volterra integral equation with noncompact kernel. - Guoqiang Han; Ken Hayami; Wang Jiong (Appl. Math. Comput., 2001)

GMRES Methods for Least Squares Problems. - Ken Hayami; Jun-Feng Yin; Tokushi Ito (SIAM J. Matrix Anal. Appl., 2010)

Greville's method for preconditioning least squares problems. - Xiaoke Cui; Ken Hayami; Jun-Feng Yin (Adv. Comput. Math., 2011)

A geometric view of Krylov subspace methods on singular systems. - Ken Hayami; Masaaki Sugihara (Numer. Linear Algebra Appl., 2011)

Inner-Iteration Krylov Subspace Methods for Least Squares Problems. - Keiichi Morikuni; Ken Hayami (SIAM J. Matrix Anal. Appl., 2013)

Corrigendum to: A geometric view of Krylov subspace methods on singular systems. - Ken Hayami; Masaaki Sugihara (Numer. Linear Algebra Appl., 2014)

Cluster Newton Method for Sampling Multiple Solutions of Underdetermined Inverse Problems: Application to a Parameter Identification Problem in Pharmacokinetics. - Yasunori Aoki; Ken Hayami; Hans De Sterck; Akihiko Konagaya (SIAM J. Sci. Comput., 2014)

Improvements to the cluster Newton method for underdetermined inverse problems. - Philippe Gaudreau; Ken Hayami; Yasunori Aoki; Hassan Safouhi; Akihiko Konagaya (J. Comput. Appl. Math., 2015)

Convergence of Inner-Iteration GMRES Methods for Rank-Deficient Least Squares Problems. - Keiichi Morikuni; Ken Hayami (SIAM J. Matrix Anal. Appl., 2015)

Jacobian-Free Implicit Inner-Iteration Preconditioner for Nonlinear Least Squares Problems. - Wei Xu; Ning Zheng; Ken Hayami (J. Sci. Comput., 2016)

Modulus-Type Inner Outer Iteration Methods for Nonnegative Constrained Least Squares Problems. - Ning Zheng; Ken Hayami; Jun-Feng Yin (SIAM J. Matrix Anal. Appl., 2016)

Modulus-based iterative methods for constrained Tikhonov regularization. - Zhong-Zhi Bai; Alessandro Buccini; Ken Hayami; Lothar Reichel; Jun-Feng Yin; Ning Zheng (J. Comput. Appl. Math., 2017)

Updating preconditioners for modified least squares problems. - José Marín; José Mas; Daniel Guerrero; Ken Hayami (Numer. Algorithms, 2017)

Implementation of interior-point methods for LP based on Krylov subspace iterative solvers with inner-iteration preconditioning. - Yiran Cui; Keiichi Morikuni; Takashi Tsuchiya; Ken Hayami (Comput. Optim. Appl., 2019)

A Stabilized GMRES Method for Solving Underdetermined Least Squares Problems. - Zeyu Liao; Ken Hayami; Keiichi Morikuni; Jun-Feng Yin (CoRR, 2020)

GMRES on singular systems revisited. - Ken Hayami; Kota Sugihara (CoRR, 2020)

Secant variable projection method for solving nonnegative separable least squares problems. - Xiongfeng Song; Wei Xu; Ken Hayami; Ning Zheng (Numer. Algorithms, 2020)

Right preconditioned MINRES for singular systems†. - Kota Sugihara; Ken Hayami; Ning Zheng (Numer. Linear Algebra Appl., 2020)

Corrigendum 2 to: A geometric view of Krylov subspace methods on singular systems. - Ken Hayami; Kota Sugihara (Numer. Linear Algebra Appl., 2021)

Kaczmarz-Type Inner-Iteration Preconditioned Flexible GMRES Methods for Consistent Linear Systems. - Yi-Shu Du; Ken Hayami; Ning Zheng; Keiichi Morikuni; Jun-Feng Yin (SIAM J. Sci. Comput., 2021)

GMRES using pseudo-inverse for range symmetric singular systems. - Kota Sugihara; Ken Hayami; Zeyu Liao (CoRR, 2022)

GMRES methods for tomographic reconstruction with an unmatched back projector. - Per Christian Hansen; Ken Hayami; Keiichi Morikuni (J. Comput. Appl. Math., 2022)

Right preconditioned GMRES for arbitrary singular systems. - Kota Sugihara; Ken Hayami (CoRR, 2023)

Recent advances in the numerical solution of matrix problems. - Ken Hayami; Keiichi Morikuni; Lothar Reichel; Ning Zheng (J. Comput. Appl. Math., 2023)

GMRES using pseudoinverse for range symmetric singular systems. - Kota Sugihara; Ken Hayami; Zeyu Liao (J. Comput. Appl. Math., 2023)

Convergence analysis of inner-iteration preconditioned GMRES. - Zeyu Liao; Ken Hayami (CoRR, 2024)

NR-SSOR right preconditioned RRGMRES for arbitrary singular systems and least squares problems. - Kouta Sugihara; Ken Hayami (CoRR, 2025)