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## [Libmesh-users] value at a point

 [Libmesh-users] value at a point From: - 2007-07-11 10:46:06 ```How can I, after finding the solution, obtain its value at an arbitrary point? For this I think is needed interpolation via MeshFunction but how to implement it? Thanks /Paulo ```

 [Libmesh-users] value at a point From: - 2007-07-11 10:46:06 ```How can I, after finding the solution, obtain its value at an arbitrary point? For this I think is needed interpolation via MeshFunction but how to implement it? Thanks /Paulo ```
 [Libmesh-users] value at a point From: John Peterson - 2007-07-11 13:23:17 ```Once you figure out which element the point is in, reinitialize the finite element object at that point. (See the FE::reinit() which takes a pointer to a vector of points.) This will recompute the shape function values at that point, which will allow you to loop over them and obtain the value as u(x) = sum_i u_i phi_i(x) -J pcorreia@... writes: > How can I, after finding the solution, obtain its value at an arbitrary > point? For this I think is needed interpolation via MeshFunction but how > to implement it? > Thanks > /Paulo ```
 Re: [Libmesh-users] value at a point From: Roy Stogner - 2007-07-11 18:31:34 ```To clarify: if you really need the solution at an *arbitrary* point, you will want to use MeshFunction, initialized with either the System's solution vector or with a localized serial copy of that vector. See exact_error_estimator.C for an example. 99% of the time, though, you already know that you want the solution on a particular local element (or better yet, on a quadrature point on that local element), and then it's much more efficient to do what John suggests. See ex13 for an example. --- Roy On Wed, 11 Jul 2007, John Peterson wrote: > Once you figure out which element the point is in, reinitialize > the finite element object at that point. (See the FE::reinit() > which takes a pointer to a vector of points.) This will recompute > the shape function values at that point, which will allow you to > loop over them and obtain the value as > > u(x) = sum_i u_i phi_i(x) > > -J > > > pcorreia@... writes: > > How can I, after finding the solution, obtain its value at an arbitrary > > point? For this I think is needed interpolation via MeshFunction but how > > to implement it? > > Thanks > > /Paulo > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > Libmesh-users mailing list > Libmesh-users@... > https://lists.sourceforge.net/lists/listinfo/libmesh-users > ```