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From: Vikram Garg <simulationist@gm...>  20110421 17:00:14

Hey, I am writing because this is either an interesting theoretical requirement I am not understanding or a bug in my code/libMesh. For my application, I want to set different penalties on different subsets of the boundary. In particular, I want a penalty of epsilon on subset A and epsilon on subset B. A and B are share a single vertex, but are otherwise disjoint. In my application, they also happen to be orthogonal to each other, i.e. they form a corner. However, if I set penalties of epsilon and epsilon on A and B, two things happen 1) The first iteration of a uniform refinement loop gives a solution that is unbounded. 2) The second iteration (a once uniformly refined mesh) gives a jacobian verification error on an element, not the side. If I just use the numerical jacobian, the solution is still unbounded. This happens even if I change my initial mesh size, i.e. the same behaviour (1 and 2) repeats, no matter what my initial mesh size is. Thanks.  Vikram Garg PhD Candidate Institute for Computational and Engineering Sciences The University of Texas at Austin http://users.ices.utexas.edu/~vikram/ http://www.runforindia.org/runners/vikramg 