2016-01-12 8:44 GMT+11:00 Junchao Zhang <junchao.zh...@gmail.com>: > Hello, > I am learning FEM by reading the Libmesh example adaptivity_ex2.C and > have two questions.
> 2) The code uses the penalty method to impose boundary conditions. I was > told the penalty method is bad and a smoothing function with zero on > boundary is preferred. Could someone point me to literatures or examples on > smoothing? Hello. I'm not sure that 'the penalty method is bad'. There can be some technical issues with it in specialized problems, but if you're only just learning FEM, I wouldn't worry about them for the moment. A good introductory reference for the penalty method is the section 'Essential boundary conditions' on pp. 121-122 of Becker, E. B., G. F. Carey, & J. T. Oden (1981). Finite Elements, An Introduction, Volume 1 of The Texas Finite Element Series. Englewood Cliffs, New Jersey: Prentice-Hall which includes: 'The penalty method is not only easy to implement and mathematically sound but it is also easy to motivate by physical arguments.' I haven't heard of the 'smoothing function' idea, but if you do need or would prefer to avoid the penalty method, libMesh does have the DirichletBoundary, as in introduction_ex4.C. ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
