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freeze (and rfreeze)

Do not allow indicated model parameters to vary. (See also thaw)

where <param range> ::= [<modelName>:]<param#>|<param#>- <param#>.

For response parameters (see gain command):

where <param range> ::= [<source number>:]<param#>|<param#>- <param#>.

The indicated model parameter or range of model parameters will be marked so they cannot be varied by the fit command. By default,the range will be the last range input by either a freeze or thaw command.

Examples:

Currently there are six parameters, initially all unfrozen.

XSPEC12> freeze 2 
//Parameter 2 is frozen
XSPEC12> freeze 4-6
//Parameters 4, 5, and 6 are frozen.
XSPEC12> thaw 2 3-5
//Parameters 2, 4, and 5 are thawed, parameter 3 is unaffected.
XSPEC12> freeze 
//Parameters 3,4,5 are frozen (the last range input by a freeze 
//or thaw command).
XSPEC12> rfreeze 4-6
//Response parameters 4, 5, and 6 are frozen.