FUNCTION synfunc_linear, x, NO_PAR_CHECK = no_par_check

; Description: For an input value "x", the function calculates and returns the value of the 
;              linear synthesis function.
;
; Input Parameters:
;
;   x - FLOAT/DOUBLE - The value of the independent variable.
;
; Return Value:
;
;   The return value is the value of the linear synthesis function as a DOUBLE.
;
; Keywords:
;
;   If the keyword NO_PAR_CHECK is set (as "/NO_PAR_CHECK"), then the program will not perform
;   parameter checking on the input parameters, reducing program overheads.
;
; Author: Dan Bramich (dmb@ing.iac.es)
;
; History:
;
;   21/08/2008 - Module created (dmb)

;Perform parameter checking if not instructed otherwise

;Calculate the value of the linear synthesis function

;Return the value of the linear synthesis function