Dear Martin, thanks for pointing out to the FEPointEvaluation class. However, my intent is to compute the gradients of shape functions in real coordinates.
" so in that case the recommendation would be to use FEValues, despite that being terribly inefficient." What is the approach to achieve this? My only idea is to create a new FEValues object for each quadrature point and pass an appropriate Quadrature object. But seems to be very inefficient. Is there an alternative way in combination with FEValues? Best, Simon Am Di., 5. Juli 2022 um 08:16 Uhr schrieb Martin Kronbichler < kronbichler.mar...@gmail.com>: > Dear Simon, > > We have the class FEPointEvalation, > https://dealii.org/developer/doxygen/deal.II/classFEPointEvaluation.html > , which implements the operation of evaluating a solution at arbitrary > points (as handed in as an array to points in unit coordinates). To do this > for positions in real coordinates, you typically need to invert the > mapping, Mapping::transform_real_to_unit_cell or > Mapping::transform_points_real_to_unit_cell, see > https://dealii.org/developer/doxygen/deal.II/classMapping.html , always > assuming that you have located the correct points. Most tasks can be > reduced to this setup. > > If your intent is not just the solution interpolation but the value of > shape functions, e.g. because you want to assemble a local matrix, > FEPointEvaluation is not directly providing that info, so in that case the > recommendation would be to use FEValues, despite that being terribly > inefficient. We could possibly integrate such functionality into > FEPointEvaluation if you have interest in that direction, so let us know > what your needs are. > > Best, > Martin > On 05.07.22 15:56, Simon wrote: > > Dear all: > > I have to compute the gradient with respect to real space co-ordinates of > the shape functions belonging to a FE_Q element at arbitrary points in the > element, that is, not only at quadrature points. > > What is the way to do this in dealii? > FEValues provides shape function values, gradients,... only at quadrature > points. > > Thank you, > Simon > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en > --- > You received this message because you are subscribed to the Google Groups > "deal.II User Group" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to dealii+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/16afc8fa-bcfe-4a81-9ade-040c18f85596n%40googlegroups.com > <https://groups.google.com/d/msgid/dealii/16afc8fa-bcfe-4a81-9ade-040c18f85596n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en > --- > You received this message because you are subscribed to the Google Groups > "deal.II User Group" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to dealii+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/34843cd0-22a6-d4b5-7cb8-f530715a6108%40gmail.com > <https://groups.google.com/d/msgid/dealii/34843cd0-22a6-d4b5-7cb8-f530715a6108%40gmail.com?utm_medium=email&utm_source=footer> > . > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/CAM50jEteHa8vhryPshNi4SGP3jhm%3DsEj_A8K6wq1TSX-aamKmQ%40mail.gmail.com.
