NEWTON [TIME LEVELS newstp] [CONVERGE {LEVEL | ORDER} newcvg]

This keyword specifies that the Global Newton time stepping algorithm is to be used. The parameter newstp specifies the number of Global Newton time levels to advance. The default value is 30.

There are two possible procedures for determining the overall global convergence.

	CONVERGE LEVEL		Convergence is assumed when | Qn - Qn-1 | < newcvg where Q represents the vector of dependent variables, and n is the Newton time level.
	CONVERGE ORDER		Convergence is assumed when | Qn - Qn-1 | / max ( | Qn - Qn-1 | ) < 10-newcvg

The default is CONVERGE ORDER 3.

Within a Newton time level, the number of cycles and iterations to be run is specified using the CYCLES and ITERATIONS keywords.

The convergence criteria within a Newton time level may be specified using the CONVERGE keyword. Note that the default for the CONVERGE keyword is a four-order of magnitude decrease in the maximum residual. If Newton iteration is being used for a steady flow problem, with the default of three orders of magnitude for the global convergence criteria, it would make sense to also use three orders of magnitude for the convergence criteria within a Newton time step.

See Also: CYCLES, ITERATIONS, CONVERGE