Preconditioner for Least-squares FEM
            
            
            
                15 Oct
                
                    2015
                
            
            
                15 Oct
                
                '15
                
            
            
            
        
    
                1:47 p.m.
            
        Hi all, I am attempting to solve Darcy's equation: u + grad[p] = 0 div[u] = f The weak form under the least-squares finite element method (LSFEM) looks like this: (u + grad[p]; v + grad[q]) + div[u]*div[v] = (f; div[v]) For H(div) elements like RT0, these options worked nicely: -ksp_type gmres -pc_type fieldsplit -pc_fieldsplit_type schur -pc_fieldsplit_schur_precondition selfp -fieldsplit_0_ksp_type preonly -fieldsplit_0_pc_type bjacobi -fieldsplit_0_sub_pc_type ilu -fieldsplir_1_ksp_type preonly -fieldsplit_1_pc_type hypre but for the above LSFEM, it does not work (get a DIVERGED_MAX_IT error). I heard multigrid methods are good for these types of problems, so how do I tweak the above parameters? Thanks, Justin
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                Justin Chang