| 850 | | ||[=#PA0648 PA0648] || No grid coarsening possible, multigrid approach effectively reduces to a Gauss-Seidel scheme. || The convergence of the pressure solver might be insufficient and the simulation can become unstable. You should try to adjust the number of subdomain grid points in a way that each of (nx+1)/npex, (ny+1)/npey, and nz contain power-of-two (2^n^) factors with at least n = 2 or larger. Alternatively, in case that you cannot change your grid, you may try to increase the number of Gauss-Seidel iterations ([../initialization_parameters#ngsrb ngsrb]) to improve convergence, but this approach is very limited. || |
| | 850 | ||[=#PA0648 PA0648] || No grid coarsening possible, multigrid approach effectively reduces to a Gauss-Seidel scheme. || The convergence of the pressure solver might be insufficient and the simulation can become unstable. You should try to adjust the number of subdomain grid points in a way that each of (nx+1)/npex, (ny+1)/npey, and nz contain power-of-two (2^n^) factors with at least n = 2 or larger. Be aware that you can change both, the total number of gridpoints of the total domain, and/or the number of PEs. Alternatively, in case that you cannot change your grid or virtual processor grid, you may try to increase the number of Gauss-Seidel iterations ([../initialization_parameters#ngsrb ngsrb]) to improve convergence, but this approach is very limited. || |
