How come when I run the same linear solver on a different number of processes it takes a different number of iterations?
The convergence of many of the preconditioners in PETSc including the the default parallel preconditioner block Jacobi depends on the number of processes. The more processes the (slightly) slower convergence it has. This is the nature of iterative solvers, the more parallelism means the more “older” information is used in the solution process hence slower convergence.
- I have a number of processes that require being started as part of a configuration and that must be run with different user logins. How do I manage this in AppCenter?
- Why do I get different results among the ANOVA Module and the Visual General Linear Models module when I run the same type of analysis on the same dataset?
- How come when I run the same linear solver on a different number of processes it takes a different number of iterations?