Hi Dr. Bangerth, Thanks for your message.
I understand it. So when computing the equation and I need it times "2*pi*r", I should call pull_back() to transform the coordinates of the cylinder's vertices to "(r, phi, z)" to get "r". Is it right? Best, LU 在2023年3月24日星期五 UTC+8 00:46:33<Wolfgang Bangerth> 写道： > On 3/23/23 10:32, RUIJIAN LU wrote: > > > > Thanks, you are right. Therefore, when I just create a triangulation by > > cylinder(), have the coordinates of its vertices already been in > > cylindrical coordinate（r, phi, z） system？(Of course, the 'z' should > > be x.) If it is right, is fe_values.quadrature_point(q_index)(0) equal > > to ‘r’, fe_values.quadrature_point(q_index)(1)equal to 'phi' and > > fe_values.quadrature_point(q_index)(0) equal to 'x'? > > deal.II only ever computes in a Cartesian coordinate system. Let's call > it x1,x2,x3. If you would like to *interpret* x1 as the radial > direction, and x2 as the angle phi, and x3 as the vertical distance z, > then that is your *choice* when you write down the equation. But the > coordinates of the cylinder's vertices are stored in x1,x2,x3. > > Best > W. > > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bang...@colostate.edu > 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. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/9c83ca03-2680-4b38-ba92-c3ce56419b8bn%40googlegroups.com.
