<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi, <div class=""><br class=""></div><div class=""> I am working on a problem with system of equations in complex numbers, and am splitting it up to solve it with petsc compiled for real number support:</div><div class=""><br class=""></div><div class=""><div class=""><div class=""><span class="" style="font-family: Monaco; font-size: 10px;">(J_R + i J_I) (x_R + i x_I) + (r_R + i r_I) = 0</span></div><div class=""><span class="" style="color: rgb(59, 170, 68); font-family: Monaco; font-size: 10px;"><br class=""></span></div><div class="">is then defined as </div><div class=""><br class=""></div><div class=""><div class="" style="margin: 0px; font-size: 10px; line-height: normal; font-family: Monaco;">[ J_R -J_I] {x_R} + {r_R} = {0}</div></div><div class="" style="margin: 0px; font-size: 10px; line-height: normal; font-family: Monaco;"><div class="" style="margin: 0px; line-height: normal;">[ J_I J_R] {x_I} + {r_I} = {0}</div></div></div><div class=""><br class="">
I have tried block-Schur solver with the Jacobian defined using the nested matrix format with a separate matrix for each quadrant of the Jacobian. This works well for diagonally dominant cases, but for high-frequency problems (J_I scales with frequency), the solver convergence is very slow. </div></div><div class=""><br class=""></div><div class="">Now, I am attempting to create a single matrix so that I can use the other ksp+pc combinations for this system of equations. </div><div class=""><br class=""></div><div class="">I am wondering if there is a natural way to create an mpiaij or an mpibaij matrix from the nested matrix defined above. </div><div class=""><br class=""></div><div class="">I would appreciate any guidance on this. </div><div class=""><br class=""></div><div class="">Regards,</div><div class="">Manav</div><div class=""><br class=""></div><div class=""><br class=""></div></body></html>