Manual Page for Command >>> STEP


Syntax
>>> STEP (UNSCALED): max_step

Parent Command
>> CONVERGENCE

Subcommand
-

Description
This command defines the maximum allowable size of the scaled (default) or unscaled (keyword UNSCALED) update vector delta(p) per iTOUGH2 iteration. The step length of the scaled parameter update vector is defined as follows:

deltaP=...

This is a global step size limitation as opposed to the one specified for each individual parameter (see command >>>> STEP). Limiting the global step size may make the inversion more stable. Parameter max_step should be chosen large enough, so that the size of the proposed step size |delta(p')| is reduced to |delta(pmax)| only during the first few iterations. The figure below illustrates that limiting the step size maintains the direction of the step taken in the parameter space.

Max Step

Example
> COMPUTATION
>> CONVERGENCE
>>> number of ITERATIONS : 10 (may need more iterations!)
>>> limit scaled STEP size to: 1.0 [dimensionless]
<<<
<<

See Also
>>>> STEP (p)


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Page updated: August 14, 1998