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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Hello PETSc users,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In our Finite Element application we would like to apply Multi-Point-Constraints to some vertices. In these Multi-Point-Constraints we force certain DoF in the following nodes to be the same as those in controlling nodes. We use DMPlex to store our mesh. I’m wondering what would be a good way to implement this together with SNES? Or is there an example that does similar thing?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Currently both right-hand-side and solution vectors in out application are created using DMCreateGlobalVec(). And we tried (unsuccessfully) to modify solution within FormRHS or FormJacobian routines but the solution vector seems to be read-only (for good reason). Is there a way to tell SNES about these constraints? Or perhaps one can somehow create a vector with only a subset of the DoFs (the actual “unknowns”)?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thank you in advance for any help or advice!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hongrui<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> <o:p></o:p></p></div></body></html>