Professor Wolfgang Thanks for your professional explanation and patient reply.
Best, Toddy 在2021年9月17日星期五 UTC+8 上午11:14:38<Wolfgang Bangerth> 写道： > On 9/16/21 7:34 PM, Toddy Liu wrote: > > > > Yes, I can write the components of V(u(x_q)) by known expression, for > example > > V(u(x_q))= (2u(x_q),3u(x_q)) where 2u(x_q) is the x-direction and > 3u(x_q) is > > y-direction. I construct a vector<Tensor> named tmp_vector and assign > the > > values by tmp_vector[0]=2u(x_q), tmp_vector[1]=3u(x_q). Then I do the > > multiplication tmp_vector*fe_values.shape_grad(i,q_point). But when I > ran the > > program, errors occurred because maybe the operation between these two > terms > > is not permitted. So I define the V(u(x_q)) by > Point<dim>(2u(x_q),3u(x_q)) and > > the program runs without errors. > > The dot product is defined between two objects of type Tensor<1,dim>. A > Point<dim> is derived from Tensor<1,dim>, so this works. Just > vector<Tensor<1,dim>> doesn't -- it should have been Tensor<1,dim>. > > Best > W. > > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: [email protected] > 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/cc66fb27-4e48-427a-8d4c-6084432569b8n%40googlegroups.com.
