<html><body><div style="color:#000; background-color:#fff; font-family:verdana, helvetica, sans-serif;font-size:10pt"><div>Hi users and developers, <br>Summer greetings from Delft. <br><br><br>For the system Au = f, I want to apply a multilevel preconditioner with a KSP (say FGMRES) . The preconditioner<br>reads as<br><br>Prec = C + M^-1 (I - A*C) , where<br><br></div><ul><li> C reads coarse grid correction operator i.e. <span style="background-color:rgb(64, 255, 255);">C = P*A_2h\R</span> [ R restriction, A_2h coarse operator, P interpolation] </li><li>M is say some sparse matrix (resembling to A) <br></li></ul><div>What makes it multilevel is I have to approximate coarse operator <span>"A_2h" with few KSP iterations preconditioned by the above defined</span></div><div><span>preconditioner "Prec" , but off course at the level 2h and hence at every coarse level until coarsest.
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only know, it can be implemented with PCMG. I am little afraid of DMMG. <br></span></div><div><span>Explanatory suggestions to customize PCMG for what is required are very appreciated. <br></span></div><div><br><span></span></div><div><span>Thanks in advance. </span></div><div><br></div><div><br></div><div>regards, <span>Abdul <br></span></div><br><div><br></div></div></body></html>