[petsc-users] GAMG failure

[Blaise Bourdin]

Hi,

I am having issue with GAMG for some very ill-conditioned 2D linearized elasticity problems (sharp variation of elastic moduli with thin  regions of nearly incompressible material). I use snes_type newtonls, linesearch_type cp, and pc_type gamg without any further options. pc_type Jacobi converges fine (although slowly of course).


I am not really surprised that gamg would not converge out of the box, but don’t know where to start to investigate the convergence failure. Can anybody help?

Blaise

— 
Canada Research Chair in Mathematical and Computational Aspects of Solid Mechanics (Tier 1)
Professor, Department of Mathematics & Statistics
Hamilton Hall room 409A, McMaster University
1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada 
https://www.math.mcmaster.ca/bourdin | +1 (905) 525 9140 ext. 27243