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9.2.3 Nonlinear Solver
Set the options for the nonlinear Newton solver which is used for the nonlinear analysis types (all analyses except the heat transfer analysis use this solver). The following options can be set.
- Displacement tolerance: convergence tolerance on displacement norm
- Energy tolerance: convergence tolerance on energy norm
- Residual tolerance: convergence tolerance on residual norm
- Line search tolerance: The convergence tolerance for the line search.
- Minimal residual: If the residual norm drops below this value, the time step will automatically converge.
- Quasi-Newton method: Select the particular variation of Newton's method that will be used by the nonlinear solver.
- Max reformations: Max number of stiffness reformations per time step
- Max BFGS updates: Max number of BFGS iterations between reformations
- Reform on diverge: When checked, the global stiffness matrix will be reformed if an iteration diverges.
- Reform each timestep: When checked, the global stiffness matrix will be reformed at the beginning of each step. For linear or slightly nonlinear problems, turning this option off may result in significant performance improvements.