|Objects Mixture||<Prev Next>|
A Variables object is used to add named dummy
parameters that are used to constrain fits.
This is particularly designed for force field
analysis (see z matrix for an example)
but can be useful in other contexts. For example, to fit to a band
origin and a separation, rather then two band origins, add a
parameter named "Offset" as above, and then add a constraint along the lines
Constrain NH3.ND2H.B.A2.Origin := Variables.Offset + NH3.ND2H.B.B1.Origin
With this set up the new parameter, effectively the difference
between the two origins, and one of the origins (NH3.ND2H.B.B1.Origin)
are floated, rather than both origins. Also see the FrequencyOffset and FrequencyScale directives, which can specify a variable, rather than a constant value.
|Global||If true, then variables given in this object are available
in all expressions. (If false, then the values will require
specifying the full name, as Variables.Offset