Thanks!! By the way, can I ask another? Actually, the quantity that I'm going to calculate is \dot(gamma), More explicitly...I attach one figure
<https://lh3.googleusercontent.com/-Af70CldxGb4/WXC1hU2HssI/AAAAAAAABDY/kTM9a2-uFmsJ1B1vNEpYoVbiDOUjGl6MgCLcBGAs/s1600/Screen%2BShot%2B2017-07-20%2Bat%2B8.50.15%2BAM.png> So I modified post processor as, template <int dim> void Magnitude<dim>::compute_derived_quantities_vector ( const std::vector<Vector< double> > & uh, const std::vector<std::vector<Tensor<1, dim> > > & duh, const std::vector<std::vector<Tensor<2, dim> > > & /*dduh*/, const std::vector<Point<dim> > & /*normals*/, const std::vector<Point<dim> > & evaluation_points, std::vector<Vector<double> > & computed_quantities) const { //const unsigned int n_quadrature_points = uh.size(); for (unsigned int i=0; i<computed_quantities.size(); i++) { Assert(computed_quantities[i].size() == 1, ExcDimensionMismatch (computed_quantities[i].size(), 1)); Assert(uh[i].size() == 3, ExcDimensionMismatch (uh[i].size(), 3)); Tensor<2,dim> grad_u; for (unsigned int d=0; d<dim; ++d) grad_u[d] = duh[i][d]; std::cout << "grad_u: " << grad_u[0][0] << " , " << grad_u[0][1] << std::end; // to check whether it actually gets value const SymmetricTensor<2,dim> shear_rate_tensor = symmetrize (grad_u); computed_quantities[q](0) = shear_rate_tensor * shear_rate_tensor + std::pow( (uh[q](0) /evaluation_points[q](0)),2) ); } } but I got problem in two ways 1. the 'grad_u' vector I actually receiving is all zero vector.... I checked and it always gives me (dudx,dudy)=(0,0) 2. I need to use p[0] value, and I believe 'evaluation_points[q](0)' is what I need. but when I extract value I am receiving error as... *grad_u: 0 , 0* *make[3]: *** [CMakeFiles/run] Segmentation fault: 11* *make[2]: *** [CMakeFiles/run.dir/all] Error 2* *make[1]: *** [CMakeFiles/run.dir/rule] Error 2* *make: *** [run] Error 2* *Thanks...* *Jaekwang * On Wednesday, July 19, 2017 at 6:02:14 PM UTC-5, Wolfgang Bangerth wrote: > > On 07/19/2017 05:00 PM, Jaekwang Kim wrote: > > /See the entry in the Frequently Asked Questions of deal.II (linked to > > from http://www.dealii.org/) for a lot more information on what this > > error means and how to fix programs in which it happens./ > > Have you looked here? :-) > > (The answer is that the `Magnitude` object needs to live at least as > long as the `DataOut` object. You should declare it *before* the > `DataOut` object.) > > Cheers > W. > > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bang...@colostate.edu > <javascript:> > www: http://www.math.colostate.edu/~bangerth/ > -- 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. For more options, visit https://groups.google.com/d/optout.
