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<p>Would you please give me an idea what combination of ksp solver and preconditioner I should use to solve this generalized symmetric hermitian problem? To get the convergence faster, do I need to use external solvers like mumps and superlu_dist?<br>
</p>
<br>
<p>Thanks</p>
<p>M Hassan<br>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Jose E. Roman <jroman@dsic.upv.es><br>
<b>Sent:</b> Monday, July 18, 2016 1:43:18 PM<br>
<b>To:</b> Hassan Md Mahmudulla<br>
<b>Cc:</b> petsc-users@mcs.anl.gov; slepc-maint@upv.es<br>
<b>Subject:</b> Re: [petsc-users] Incorrect eigenvalues</font>
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<div class="PlainText">[Please do not send queries to both petsc-users and slepc-maint, only one of them is enough.]<br>
<br>
It seems that you are mixing a random number of options that make little sense. You cannot use preonly+jacobi to solve linear systems, even less in the case of the eps_interval option. For computing eigenvalues in an interval, follow the instructions in section
3.4.5 of the users manual. In particular, preonly+cholesky is required. Also, if done with MUMPS the option -mat_mumps_icntl_13 1 is also needed. Furthermore, I don't see that you are using -st_type sinvert, so I guess some options are inserted in the source
code, which you did not show.<br>
<br>
Jose<br>
<br>
<br>
> El 18 jul 2016, a las 21:01, Hassan Md Mahmudulla <mhassan@miners.utep.edu> escribió:<br>
> <br>
> Hi all,<br>
> I have been trying to solve generalized eigenvalue problem using matrices of size 10K. Sparsity of the matrix is 6%. I am using the following command
<br>
> <br>
> ./solver -f1 hamold.petsc -f2 ovlbaby.petsc -st_ksp_type preonly -st_pc_type jacobi -st_pc_factor_mat_solver_package mumps -eps_interval -2,0 -eps_nev 1000<br>
> <br>
> • solver is the program<br>
> • f1 and f2 are the input file for both matrices in petsc binary (mpiaij)<br>
> I am getting the following output:<br>
> <br>
> <br>
> Generalized eigenproblem stored in file.<br>
> <br>
> Reading REAL matrices from binary files...<br>
> TYPE OF MATRIX A: mpiaij<br>
> TYPE OF MATRIX B: mpiaij<br>
> Solving for Eigen values...<br>
> Solved! <br>
> 1: -9771.8339 0<br>
> 2: -9559.8347 0<br>
> 3: -9408.5603 0<br>
> 4: -9387.423 0<br>
> 5: -9235.9137 0<br>
> 6: -9102.5334 0<br>
> 7: -9098.1307 0<br>
> 8: -8970.3594 0<br>
> 9: -8854.4964 0<br>
> 10: -8850.3629 0<br>
> 11: -8736.6619 0<br>
> 12: -8637.1749 0<br>
> 13: -8628.214 0<br>
> 14: -8524.2494 0<br>
> 15: -8440.0801 0<br>
> 16: -8424.1789 0<br>
> 17: -8327.5389 0<br>
> 18: -8257.7763 0<br>
> 19: -8233.9564 0<br>
> 20: -8143.1251 0<br>
> 21: -8086.9865 0<br>
> 22: -8054.7899 0<br>
> 23: -7968.7355 0<br>
> 24: -7925.5421 0<br>
> 25: -7884.7777 0<br>
> 26: -7802.7577 0<br>
> 27: -7771.913 0<br>
> 28: -7722.537 0<br>
> 29: -7643.9943 0<br>
> 30: -7624.9684 0<br>
> <br>
> .........................<br>
> .........................<br>
> <br>
> 541: -24.947288 0<br>
> 542: -24.945875 0<br>
> 543: -24.94017 0<br>
> <br>
> <br>
> First column is the eigenvalues. <br>
> My concern is, <br>
> • Eigenvalues are not right<br>
> • I defined the interval but still it's giving me eigenvalues outside of that interval<br>
> Please help me out.<br>
> <br>
> M Hassan<br>
<br>
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