Ok! I will try it. Runfeng
Jose E. Roman <[email protected]> 于2022年7月13日周三 14:10写道： > > > > El 13 jul 2022, a las 7:59, Runfeng Jin <[email protected]> escribió: > > > > Thank you, I will have a try to them. > > > > I use JD and GD because this matrix is about quantum chemical computing, > and it has the property that diagonal elements dominate. This property > seems to be suitable for JG and GD. > > This is useful if you want to use a diagonal preconditioner (classical > Davidson), but generalized Davidson can take any preconditioner. In PETSc > the default preconditioner is not Jacobi but Block Jacobi+ILU. > > > > > > JD and GD are best when you need to compute eigenvalues around a target > > About this, I want to compute only three smallest real eigenvalues, > should this be the situation suitable for GD and JD？ > > No, try Krylov-Schur or LOBPCG. > > > > > Runfeng > > > > Jose E. Roman <[email protected]> 于2022年7月13日周三 12:36写道： > > Does it work with -eps_gd_blocksize 1 ? > > Why do you want to use GD? JD and GD are best when you need to compute > eigenvalues around a target. For your case, I would try with the default > solver (Krylov-Schur) or with LOBPCG. > > > > Jose > > > > > > > El 13 jul 2022, a las 4:59, Runfeng Jin <[email protected]> > escribió: > > > > > > Hi! > > > I am trying to find 3 eigenvalues of a matrix 81,160*81,160, and it > get 0 eigenvalue after 162320 iterations. I use -eps_monitor and find > error estimation floats over 1e-6, I didn't set the tolerance so it should > be the default 1e-8. Actually it should achieve 1e-10. > > > > > > I have tried JD and GD, both of them can not converge. Does there any > ways to help it converge to the 1e-10? > > > > > > By the way, I use default Convergence criterion, the output of > -log_view and -eps_monitor are shown in attachment. > > > Thank you! > > > > > > Runfeng Jin > > > <eps_monitor-and-log_view.txt> > > > >
