Re: [deal.II] discontinous contour over elements

2020-01-18 Thread David Eaton
I just use tecplot directly visualize the results. The vorticity contour from my simple code is continuous, and the results from deal.II is discontinuous (without L2 projection). Is it possible that the direct solver in Intel mkl did a similar projection step internally? ___

Re: [deal.II] Re: Application of inverse mass matrix in matrix-free context using cell_loop instead of scale()

2020-01-18 Thread Daniel Arndt
Maxi, As usual, it is much easier to help if you provide a complete minimal example and say how the result differs from what you expect. Does it only scale certain vector entries? Are the results correct when running with one MPI process? How does your approach differ from https://github.com/deali

[deal.II] Re: Application of inverse mass matrix in matrix-free context using cell_loop instead of scale()

2020-01-18 Thread 'Maxi Miller' via deal.II User Group
I tried implementing it as data.cell_loop(&LaplaceOperator::local_apply_cell, this, dst, src, //true, [&](const unsigned int start_range, const unsigned int end_range){

Re: [deal.II] discontinous contour over elements

2020-01-18 Thread Wolfgang Bangerth
On 1/18/20 9:25 AM, David Eaton wrote: > Thank you for your explanations. Basically I formed a weak form of the PDE > for > one element and numerically integrate it at the Gaussian points based on the > interpolation from the local nodes. Subsequently, I assemble the weak forms > from all eleme

Re: [deal.II] discontinous contour over elements

2020-01-18 Thread David Eaton
Thank you for your explanations. Basically I formed a weak form of the PDE for one element and numerically integrate it at the Gaussian points based on the interpolation from the local nodes. Subsequently, I assemble the weak forms from all elements into a global system matrix based on a local-t

[deal.II] Re: Application of inverse mass matrix in matrix-free context using cell_loop instead of scale()

2020-01-18 Thread 'peterrum' via deal.II User Group
Yes, like here https://github.com/dealii/dealii/blob/b84270a1d4099292be5b3d43c2ea65f3ee005919/tests/matrix_free/pre_and_post_loops_01.cc#L100-L121 On Saturday, 18 January 2020 12:57:24 UTC+1, Maxi Miller wrote: > > In step-48 the inverse mass matrix is applied by moving the inverse data > into

Re: [deal.II] discontinous contour over elements

2020-01-18 Thread Wolfgang Bangerth
On 1/17/20 9:11 PM, David Eaton wrote: > > Thanks the help from you and the others. The issue of discontinuous vorticity > field is resolved. Theoretically, I understand the gradient should be > discontinuous for C0 elements.  However, I still want to convince myself with > a explanation. while

[deal.II] Re: Application of inverse mass matrix in matrix-free context using cell_loop instead of scale()

2020-01-18 Thread 'Maxi Miller' via deal.II User Group
I.e. I should add an elementwise multiplication with the inverse mass matrix vector as postprocessing function? -- 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 y

[deal.II] Re: Application of inverse mass matrix in matrix-free context using cell_loop instead of scale()

2020-01-18 Thread 'peterrum' via deal.II User Group
Hi Maxi, I guess I am not the correct person to explain you the reason for that assert. But what you are doing is that while calling scale you are messing with the ghost values (which prevents the compress step). You should do it only locally. What you might want to check it out are the new `

[deal.II] Application of inverse mass matrix in matrix-free context using cell_loop instead of scale()

2020-01-18 Thread 'Maxi Miller' via deal.II User Group
In step-48 the inverse mass matrix is applied by moving the inverse data into a vector and applying the function scale(), i.e. as in the following code: data.cell_loop(&LaplaceOperator::local_apply_cell, this, dst, src,

Re: [deal.II] Implementation of a solver for the non-linear diffusion equation using the TimeStepping-Class

2020-01-18 Thread masod sadipour
Dear Maxi, I am not an expert in deal.ii. I have a project which is very similar to your project. I was wondering if it is possible to contact you. Best, On Sat, 18 Jan 2020, 14:41 'Maxi Miller' via deal.II User Group, < dealii@googlegroups.com> wrote: > I tried to implement a solver for the non

[deal.II] Implementation of non-linear diffusion equation using the TimeStepping-Class and matrix-free routines

2020-01-18 Thread 'Maxi Miller' via deal.II User Group
I tried to implement a solver for the non-linear diffusion equation (\partial_t u = grad(u(grad u)) - f) using the TimeStepping-Class, the EmbeddedExplicitRungeKutta-Method and (for assembly) the matrix-free approach. For initial tests I used the linear heat equation with the solution u = exp(-

[deal.II] Implementation of a solver for the non-linear diffusion equation using the TimeStepping-Class

2020-01-18 Thread 'Maxi Miller' via deal.II User Group
I tried to implement a solver for the non-linear diffusion equation (\partial_t u = grad(u(grad u)) - f) using the TimeStepping-Class, the EmbeddedExplicitRungeKutta-Method and (for assembly) the matrix-free approach. For initial tests I used the linear heat equation with the solution u = exp(-