**Syntax**

` >>>> FACTOR`

**Parent Command**

all third-level commands in block` > PARAMETER`

**Subcommand**

` -
`

**Description**

The parameter to be estimated is a factor with which the initial parameter guess is multiplied.

X=p*X0 <=> p=X/X0Here, p is the estimated parameter, X is the TOUGH2 parameter, and X0 is the initial value of the TOUGH2 parameter. This option is useful to estimate a scaling factor for variable initial and boundary conditions, or to determine the mean of a quantity while maintaining ratios (e.g., if estimating a common factor applied to all three permeability values in a model domain, the anisotropy ratio remains constant). If the factor is log-normally distributed, add command `>>>> LOGARITHM` or use command `>>>> LOG(F).` Estimating a factor is opposed to estimating the parameter value directly (command `>>>> VALUE)` or its logarithm (command `>>>> LOGARITHM` (p)).

**Example**

` > PARAMETER
>> ABSOLUTE permeability
>>> MATERIAL: CLAY1 SAND1
>>>> estimate multiplication FACTOR, and maintain both the
anisotropy ratio within a layer as well as the permeability
ratio between clay and sand.
>>>> INDEX : 1 2 3
>>>> initial GUESS: 1.0 (default)
>>>> RANGE : 0.01 100.0
<<<<
<<<
<<`

**See Also**

` >>>> LOGARITHM (p) | >>>> LOG(F) | >>>> VALUE
`