**Syntax**

` >>>> GUESS: guess`

**Parent Command**

all third-level commands in block` > PARAMETER`

**Subcommand**

` -`

**Description**

This command provides an initial guess of the parameter to be estimated. If neither this command nor command `>> GUESS` is used, the initial guess is taken from the TOUGH2 input file. The initial guess is the starting point for the minimization algorithm, to be distinguished from prior information (see command `>>>> PRIOR).` The initial guess can be overwritten by the second-level command `>> GUESS.` If command `>>>> LOGARITHM` is present, the initial guess is the logarithm of the parameter. Similarly, if command `>>>> FACTOR` is present, the initial guess should be a multiplication factor (default is 1.0).

**Example**

` > PARAMETER
>> ABSOLUTE permeability
>>> ROCK types: CLAY1 CLAY2 CLAY3 BOUND
>>>> FACTOR
>>>> initial GUESS : 1.0
>>>> is not WEIGHTed : 0.0 (default)
<<<<
>>> ROCK type : SAND1
>>>> LOGARITHM
>>>> PRIOR information : -12.0
>>>> standard DEVIATION: 1.0 order of magnitude
<<<<
<<<`

>> GUESS, i.e., starting point for optimization

2 -13.0

<<

**See Also**

` >> GUESS | >>>> PRIOR | >>>> DEVIATION (p) | >>>> VARIATION
`