From: Roy Stogner <roystgnr@ic...>  20110415 20:07:02

On Fri, 15 Apr 2011, Boyce Griffith wrote: > Is there a function that gives the reference coordinates for each node > of a (Lagrange) element? The first thing that comes to mind: initialize a firstorder monomial FE on the element with trapezoidal quadrature, then at point p evaluate xi/eta/zeta from get_phi()[1/2/3][p]. There's probably a better way to do it, though. > The reason I ask is that I have a variable, say x(X), restricted to a > particular side of a particular element for which I would like to > identify any positions at which x(X0) = x0. If any such positions > exist, I then need to evaluate some other field variables at those > locations, which I can easily accomplish if I know the reference > coordinates corresponding to position X0, but not if I only know the > value(s) of X0. Just use inverse_map()? That way you can also handle offnode positions.  Roy 