PRO fwhm_g1dfunc, x, a, f, pder

; Description: This module is for use within the function "fwhm_g1dfit.pro".
;              No parameter checking is carried out to minimise overheads in
;              the fitting process.
;
; Author: Dan Bramich (dan.bramich@hotmail.co.uk)
;
; History:
;
;   24/04/2009 - Further module optimisation performed (dmb).
;   06/05/2008 - Module created (dmb).

;Use the input vector to calculate the function values

;Return if partial derivatives are not needed

;Otherwise calculate the partial derivatives