> El 17/9/2015, a las 21:33, Xujun Zhao <[email protected]> escribió: > > Hi Jose, > > This is only a very simple test. 2 outer iterations perform 24 MatMult > operation, which means I have to solve a Finite element system with millions > of DOFs for 24 times. This is only for a polymer system with two beads. For a > polymer chain with hundreds of beads and springs, I need more outer > iterations to get its max/min eigenvalues, which means I have to perform more > computations of the finite element system. Those solves happen only for one > time step. When polymer beads move, I need to redo everything. > > In other words, the eigenvalues (max and min) have to be solved every time > step or every several time steps. Therefore, it is very expensive! My > question is that if It is possible to use the eigenvalues obtained from last > time step as an initial guess to accelerate the convergence. Thank you for > your help. > > Xujun
Eigenvalues cannot be used as initial guess. You can try passing the previous eigenvector with EPSSetInitialSpace(), but there is no guarantee it is effective to improve convergence. Jose
