Re: [deal.II] Lagrange multipliers

On 08/08/2017 11:16 AM, neverwoke wrote: Hello all. I am very new to the community but very eager to learn. I am wonder if there is an out-of-the-box support for using Lagrange multipliers on a boundary, to enforce rigid body motion in Stokes flow, similar to the work of Glowinski [1] or Hwang

Re: [deal.II] Setting off-diagonal elements in the matrix

On 08/08/2017 05:07 AM, 'Maxi Miller' via deal.II User Group wrote: Having a coupled set of poisson-like equations \partial_t a = \nabla^2 a \partial_t b = \nabla^2 b + \nabla^2 a I can write the weak form(s) as (while ignoring boundary conditions) \partial_t a = (\nabla v_1, \nabla a)

Re: [deal.II] Extracting Shape Laplacian

On 08/09/2017 05:40 PM, ky...@math.uh.edu wrote: I did try looking at the documentation for FEValuesViews::Vector < dim, spacedim >::hessian(const unsigned int shape_function, const unsigned int q_point) before

[deal.II] Line Integral of function

Hello everyone, I am using deal.ii to solve a 3D solid mechanics problem. My code uses PetSc and P4est. The geometry is a cubical box [0 1] X [0 1] X [0 1] with a uniform rectilinear mesh in the domain. I have obtained the scalar solution vector u in the domain. I need to find the line

Re: [deal.II] Re: Can we say that the higher order method, the more accurate?

Dear Matrin Thank you very much! It is exactly the problem of "mapping", in my calculation of the drag/lift coefficient, a "mapping" is not added as the first argument to the FEFaceValues constructor. After this fixed, the result looks much better. Once again, thanks for your kind help!

Re: [deal.II] Re: Can we say that the higher order method, the more accurate?

Dear Jaekwang, Thanks for your code, I do come with the same problem as yours! After adding a "mapping" to the constructor of the FEFaceValues in my code, the problem solved~ Best, Howe 在 2017年8月10日星期四 UTC+8上午3:26:00，Jaekwang Kim写道： > > Dear Howe > > I have solved this problem before, but I