<div class="gmail_quote">On Tue, Mar 6, 2012 at 08:50, Abdul Hanan Sheikh <span dir="ltr"><<a href="mailto:hanangul12@yahoo.co.uk">hanangul12@yahoo.co.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><span>I had to implement the projection preconditioner (P = I - A*R*(A_H)^1 *P) along with an standard preconditioner (M).</span></div><div><span>And I read in some thread of users list that multilevel preconditioner can </span><span>better handled by PCMG too, thus </span></div>
<div><span>I had tried to implement the later (M) as pre smoother, where as the earlier (P) as CGC in PCMG framework. <br></span></div><br>1. Does it make sense ? <br>or the coarse grid correction of PCMG only does <span>this part: R*(A_H)^1 *</span>P ?? <br>
2. How can I adapt my projection preconditioner (P) as (P1 = <span>I - A*R*(A_H)^1 *P</span> + <span>R*(A_H)^1 *P ) ? </span></blockquote></div><br><div>It's still not clear exactly what you want the method to do. PCMG can do additive or multiplicative cycles. For more general composition, see</div>
<div><br></div><div><a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCCOMPOSITE.html">http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCCOMPOSITE.html</a></div><div><a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCGALERKIN.html">http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCGALERKIN.html</a></div>
<div><br></div><div>I see the man pages are lacking details, the user's manual has more details.</div>