3.2.5.4. Modified Newton Algorithm

algorithm ModifiedNewton <-initial> <-factorOnce>

Argument	Type	Description
-initial	string	optional flag to indicate to use initial stiffness iterations
-factorOnce	string	optional flag to assemble and factor the tangent in the first analysis step, keep it fixed in all later steps, and update it only after a domain change (for example, nodes or elements added or removed).

Note

Modified Newton already uses one tangent per equilibrium solve within each analysis step. -factorOnce carries that same tangent forward to later steps instead of reforming it each time. The fixed matrix is the current tangent by default, or the initial tangent with -initial. Specifying -initial also enables -factorOnce automatically.

This command is used to construct a ModifiedNewton algorithm object, which uses the modified newton-raphson algorithm to solve the nonlinear residual equation.