From: Michael Schindler <mschindler@us...>  20040524 18:18:44

Hello, I am trying to implement boundary conditions (for the NavierStokes equation of example 13) via Lagrange multipliers. For this I need extra degreesoffreedom for every boundaryside of an element. One possibility, that already works, is to define an extra variable. But this has then DOFs at all elements of the mesh  far too many. This makes the System unnecessary large. Therefore, I would like to know: 1. Is there a readymade way to implement Lagrange multipliers? or 2. Can I "throw away" DOFs of one specified variable where I do not want to calculate its solution? 3. Can I add DOFs to a System without adding a variable? Many thanks, Michael.  Have a look at PyX: http://pyx.sourceforge.net 