<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><br class=""></div> Ok, this is embarrassing, all the code is there and the documentation, but it is not wired up to be usable; I'm not sure how that happened. The code was contributed over two years ago, and I have no memory of why it would be there but not wired up. I wired it up and ran a simple test and got MPI errors, so I suspect that the code had serious bugs we did not understand and so was not wired up; <div class=""><br class=""></div><div class=""> There are other pipelined GMRES KSPPGMRES and KSPPIPEFGMRES that are wired up and should be usable out of the box. Plus a pipelined bcgs. I suggest starting by trying those.</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""> Barry</div><div class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Aug 2, 2022, at 12:18 PM, Frank Bramkamp <<a href="mailto:bramkamp@nsc.liu.se" class="">bramkamp@nsc.liu.se</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Dear PETSc team,<div class=""><br class=""></div><div class="">I have seen that there is the KSP method: KSPAGMRES,</div><div class=""><a href="https://petsc.org/release/docs/manualpages/KSP/KSPAGMRES.html" class="">https://petsc.org/release/docs/manualpages/KSP/KSPAGMRES.html</a></div><div class=""><br class=""></div><div class="">I wanted to test this method, as it also seems to reduce the amount of MPI communication, compared</div><div class="">to the standard GMRES. </div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">I supposed that the class is called “KSPAGMRES”.</div><div class="">But in the include files petscksp.h and petsc/finclude/petscksp.h </div><div class="">there is no definition for KSPAGMRES, just KSPDGMRES.</div><div class=""><br class=""></div><div class="">I wonder if the definition KSPAGMRES is simply missing, or do I have to call</div><div class="">DGMRES and set another option for AGMRES ?!</div><div class=""><br class=""></div><div class="">The standard GMRES has the problem that MPI_Allreduce gets expensive for 2048 cores.</div><div class="">Therefore I wanted to see, if AGMRES has a bit less communication, as this is mentioned in the description</div><div class="">of the method. </div><div class=""><br class=""></div><div class="">Greetings, Frank Bramkamp</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div></div></div></blockquote></div><br class=""></div></body></html>