Sensitivity Analysis

2) Sensitivity Analysis

This section controls both static sensitivity-based parameter selection and on-the-fly periodic sensitivity analysis during optimization.

Keyword	Default value	Description
sensi_d	0.1	Derivative step multiplier applied to parameter uncertainty in sensitivity analysis.
cumul_sensi	0.95	Cumulative sensitivity threshold (0 to 1) used to select active parameters.
active_p	[]	Explicit list of parameters to perturb. If set, it bypasses sensitivity-based selection.
SA_start	1	Generation index to start on-the-fly sensitivity analysis.
SA_end	80	Generation index to stop on-the-fly sensitivity analysis.
SA_freq	20	Frequency (in generations) for running on-the-fly sensitivity updates.

The derivative step is direction-dependent and set by the parameter's class. For multiplicative parameters (if, sfc, mrc, bfc, frequencies) the step is multiplicative: with factor f = 1 + (uc - 1) * sensi_d (where uc is the parameter uncertainty), the up step is value * f and the down step is value / f (e.g. uc = 1.1, sensi_d = 0.1 → perturbed values [value / 1.01, value * 1.01]). Additive and percentage parameters use a symmetric step, value + scale * sensi_d * side.