12.21.5. - Referring to parameters
The internal storage of parameters and related values are in the structure array named
fpar, defined in
p_fitsize.h.
The next lines
show how to refer to the parameters in your model equation.
#define CONST fpar[0].p_b #define fCONST fpar[0].p_fit #define dCONST fpar[0].p_p #define LINEAR fpar[1].p_b #define fLINEAR fpar[1].p_fit #define dLINEAR fpar[1].p_pThe purpose of the above definitions is to make referencing the current values of the parameters convenient. The structure member
fpar[i].p_b indicates the current value of the
i-th
parameter.
The other
two members are relevant generally only when you are supplying the
analytic derivatives for the corresponding parameter.
In such a case
fpar[i].p_fit indicates the parameter is currently being fit
and
fpar[i].p_p is the variable to which you assign the value
of the derivative.
Their use is made clear below.