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StepMech[t] steps the constraint equations through one iteration of the Newton-Rhapson solution block with time set to t, regardless of any convergence criteria.
StepMech[] uses no value of time.
StepMech[rules] takes the supplied list of rules and uses them as initial values for the next step.

StepMech can be used to help diagnose nonconvergent models by examining the direction that Newton's method steps the solution vector.
• The following options can be given:

• See also: SolveMech.

Further Examples

Load the Modeler2D package and define a simple model.

Because the model is dependent on time, T, SolveMech can be called with a single argument giving the value of time.

If given a list of time values, SolveMech seeks a solution at each value, or at each time value plus additional time values evenly dispersed among those explicitly given.

The Solution option controls what order solution is sought, and whether to solve for the Lagrange multipliers.

Solution rules can also be output as InterpolatingFunction objects. Note that constant values are recognized and not interpolated.


By changing the ZeroTest we can make SolveMech seek a more accurate solution.

Or we can iterate toward the solution one step at a time with StepMech.

See HelpModel2D.