On Wed, May 24, 2017 at 2:21 AM, Danyang Su <[email protected]> wrote:
> Dear All, > > I use PCFactorSetLevels for ILU and PCFactorSetFill for other > preconditioning in my code to help solve the problems that the default > option is hard to solve. However, I found the latter one, PCFactorSetFill > does not take effect for my problem. The matrices and rhs as well as the > solutions are attached from the link below. I obtain the solution using > hypre preconditioner and it takes 7 and 38 iterations for matrix 1 and > matrix 2. However, if I use other preconditioner, the solver just failed at > the first matrix. I have tested this matrix using the native sequential > solver (not PETSc) with ILU preconditioning. If I set the incomplete > factorization level to 0, this sequential solver will take more than 100 > iterations. If I increase the factorization level to 1 or more, it just > takes several iterations. This remind me that the PC factor for this > matrices should be increased. However, when I tried it in PETSc, it just > does not work. > > Matrix and rhs can be obtained from the link below. > > https://eilinator.eos.ubc.ca:8443/index.php/s/CalUcq9CMeblk4R > > Would anyone help to check if you can make this work by increasing the PC > factor level or fill? > We have ILU(k) supported in serial. However ILU(dt) which takes a tolerance only works through Hypre http://www.mcs.anl.gov/petsc/documentation/linearsolvertable.html I recommend you try SuperLU or MUMPS, which can both be downloaded automatically by configure, and do a full sparse LU. Thanks, Matt > Thanks and regards, > > Danyang > > > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener http://www.caam.rice.edu/~mk51/
