Hessian computation for fitted distance detection function model parameters

Computes hessian to be used for variance-covariance matrix. The hessian is the outer product of the vector of first partials (see pg 62 of Buckland et al 2002).

Usage

flt.var(ddfobj, misc.options)

Arguments

ddfobj

distance sampling object

misc.options

width-transect width (W); int.range-integration range for observations; showit-0 to 3 controls level of iteration printing; integral.numeric-if TRUE integral is computed numerically rather than analytically

Value

variance-covariance matrix of parameters in the detection function

Note

This is an internal function used by ddf.ds to fit distance sampling detection functions. It is not intended for the user to invoke this function but it is documented here for completeness.

References

Buckland et al. 2002

See also

flnl,flpt.lnl,ddf.ds

Author

Jeff Laake and David L Miller