FUNCTION synfunc_linear, x, NO_PAR_CHECK = no_par_check

; Description: For an input parameter "x", the function calculates and returns the value of the
;              linear synthesis function. The input parameter "x" may be a scalar, vector or 
;              array.
;
; Input Parameters:
;
;   x - FLOAT/DOUBLE SCALAR/VECTOR/ARRAY - The value of the independent variable.
;
; Return Value:
;
;   The return value is a SCALAR/VECTOR/ARRAY (the same as the input parameter) of DOUBLE
;   type that takes the value of the linear synthesis function.
;
; Keywords:
;
;   If the keyword NO_PAR_CHECK is set (as "/NO_PAR_CHECK"), then the program will not perform
;   parameter checking on the input parameter, reducing program overheads. If the input
;   parameter is not of the correct number type, then the function will return a value of "0.0".
;
; Author: Dan Bramich (dan.bramich@hotmail.co.uk)
;
; History:
;
;   21/04/2009 - Module expanded to accept vectors and arrays for the input parameter (dmb).
;   21/08/2008 - Module created (dmb)

;Perform parameter checking if not instructed otherwise

;If the input parameter is a scalar, then calculate the value of the linear synthesis function

  ;Calculate the value of the linear synthesis function

;If the input parameter is a vector or an array, then calculate the set of values of the linear
;synthesis function

  ;Calculate the set of values of the linear synthesis function

;Return the value(s) of the linear synthesis function