<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt"><div>Hello,</div><div> </div><div>I am using PETSc ksp solver to solve a problem on a physical domain. The domain is splitted to subdomains in such a way that there is no connections between them, but I still have to solve the whole domain as a single linear system. My questions are:</div><div> </div><div>1. Does PETSc detect that the matrix is a block diagonal matrix and solve it efficiently?</div><div>2. In parallel solve, each subdoamin is assigned to a separate process. Does PETSc solve the system efficiently by avoiding all the unnecessary parallel message passing since there is no connections between processes?</div><div> </div><div>Thanks,</div><div>Qin</div></div></body></html>