The Inversion Controls 2 pane is on the PEST Properties dialog box under Control Data.
The variables specified on the Inversion Controls 2 pane are described in the PEST User Manual, Part I, Sections 4.2.8, 3.5.7, 6.4,and 7. More extensive descriptions of these variables are in the PEST user manual.
PHIREDSWH If the parameter-group-specific FORCEN variable appearing in the “parameter groups” section of the PEST control file is set to “switch” or “switch_5”, then PEST will switch from single to three-point or five-point derivatives calculation if the inversion process appears to be slowing. Switching takes place if the relative reduction in the objective function between successive iterations is less than the user-supplied value for PHIREDSWH. A value of 0.1 is often suitable for PHIREDSWH. Note that PHIREDSWH should be set considerably higher than the input variable PHIREDSTP which sets one of the termination criteria on the basis of the relative objective function reduction between iterations.
NOPTSWITCH The optional NOPTSWITCH variable can be used to delay the onset of higher order derivatives calculation. NOPTSWITCH must be 1 or greater. If it is greater than 1, PEST will not switch to higher order derivatives calculation until the NOPTSWITCH’th iteration at least, as long as the objective function does not rise during any iteration. If the objective function does, in fact, rise, then the NOPTSWITCH setting is overridden and PEST switches to higher order derivatives calculation anyway. The optimal value for NOPTSWITCH is case-specific; however a value of 3 or 4 often works well.
SPLITSWH determines when, in the inversion process, split slope analysis begins. (See section 3.5.7 of the PEST User Manual.) Split slope analysis provides a mechanism for reducing the deleterious impacts of poor model numerical performance on finite-difference derivatives calculation. If SPLITSWH is provided with a zero or negative value it is ignored.
DOAUI is used to activate or deactivate automatic user intervention. Because ModelMuse does not support creating the automatic user intervention section of the control file, PEST will use default values for performing automatic user intervention. If implemented in a certain way, automatic user intervention can defend the inversion process against threats posed by poor finite-difference derivatives born of model numerical granularity. This mode of implementation is activated by setting “aui” to “auid”. See section 6.4 of the PEST User Manual for details.
DOSENREUSE If DOSENREUSE is used to activate or deactivate sensitivity reuse. Because ModelMuse does not support creating the sensitivity reuse section of the control file, PEST will use default values for performing sensitivity reuse. On most occasions of PEST usage there is little benefit to be gained from invoking PEST’s sensitivity reuse functionality.
BOUNDSCALE is used to activate of deactivate bounds scaling. Under some circumstances, it is helpful to transform parameters so that they all have similar standard deviations. If bounds scaling is activated. PEST uses the upper and lower bounds of the parameter values to perform such scaling.
