Re: [deal.II] Eigenvalues and Eigenvectors of BlockSparse Matrix

2020-09-27 Thread Jean-Paul Pelteret
I’m afraid I’m not familiar with the working of the Arpack solver so I can’t be of much more help to you. As you’ve pointed out, it looks like there may be some open questions that correlate with the questions you’ve asked. Maybe someone who actually uses, or has used, this solver might be able

Re: [deal.II] Function apply_boundary_values()

2020-09-27 Thread Wolfgang Bangerth
On 9/25/20 4:15 PM, Xuefeng Li wrote: For step-26, because system_rhs depends on time and time_step, we need to assemble system_rhs in the loop. We therefore need to call apply_boundary_values() inside the loop. Here is my question. *If system_matrix were independent of time and time_step*

Re: [deal.II] Re: install problems with clang@12.0.0 and Xcode12.0 from spack

2020-09-27 Thread Wolfgang Bangerth
On 9/26/20 6:21 AM, 'Alexander Greiner' via deal.II User Group wrote: thank you for your response. Unfortunately, I am still receiving the 'same' error message. This time: Error: ProcessError: Command exited with status 2: 'make' '-j2' Are there any other suggestions what I could try? The

Re: [deal.II] Eigenvalues and Eigenvectors of BlockSparse Matrix

2020-09-27 Thread Animesh Rastogi IIT Gandhinagar
Hi Jean, I need a few more clarifications. Sorry to bother you again. In my code, when I am using the argument - "smallest_magnitude" for the type of eigenvalue, I am getting a large eigenvalue than when I am using the argument "largest_eigenvalue". I looked at some of the previous

Re: [deal.II] Eigenvalues and Eigenvectors of BlockSparse Matrix

2020-09-27 Thread Animesh Rastogi IIT Gandhinagar
Hi Jean, Thanks a lot for your detailed answer. Using this idea, I was able to solve the standard eigenvalue problem. Thanks again! Animesh On Saturday, September 26, 2020 at 1:49:10 AM UTC+5:30 Jean-Paul Pelteret wrote: > Hi Animesh, > > I’m glad to hear that you’ve gotten Arpack working,

Re: [deal.II] Re: Evaluating FE-solution on distributed mesh, semi-Lagrangian method

2020-09-27 Thread heena patel
Hi Konrad, I have the following suggestion. You can use (1) https://www.dealii.org/current/doxygen/deal.II/p4est__wrappers_8cc.html check *vertices_with_ghost_neighbors*. (2)*p4est_search_local *check link https://github.com/cburstedde/p4est/blob/master/src/p4est_search.h

Re: [deal.II] Re: Evaluating FE-solution on distributed mesh, semi-Lagrangian method

2020-09-27 Thread Konrad Simon
Dear all, I finally had time to go back to my code. Quick problem summary: I am currently working on a semi-Lagrangian method for an advection-diffusion equation with a multiscale method that I designed for advection dominated processes. During runtime I must evaluate the (known) multiscale