FUNCTION gaussian_1d_vec, hsize, fwhm, x0, hires

; Description: This function creates a one-dimensional output pixel vector representing a Gaussian
;              profile with a FWHM of "fwhm" pixels, and its centre at the pixel coordinates 
;              "hsize + 0.5 + x0". The output pixel vector is returned as a vector of length 
;              "(2*hsize) + 1" pixels. The pixel values are calculated from a pixel grid that samples 
;              the Gaussian profile at "hires" times the resolution of the output pixel vector, which
;              gives the user the option of accurately calculating the integrals over the discrete 
;              pixels. Finally, the output pixel vector is normalised to a peak value of 1.
;
; Input Parameters:
;
;   hsize - INTEGER/LONG - The output pixel vector is returned as a vector of length "(2*hsize) + 1" 
;                          pixels. If this parameter is negative, then it will be reset to "0".
;   fwhm - FLOAT/DOUBLE - The Gaussian FWHM (pix). This parameter must be positive, or the function
;                         will fail and return a value of "0.0".
;   x0 - FLOAT/DOUBLE - The offset of the Gaussian centre from the centre of the output pixel vector 
;                       (pix).
;   hires - INTEGER/LONG - The oversampling factor to be used to calculate the output pixel vector. This
;                          parameter has a minimum allowed value of "1", corresponding to no 
;                          oversampling, and a maximum allowed value of "10", to protect against 
;                          unnecessary oversampling using too much memory allocation.
;
; Return Value:
;
;   The function returns a pixel vector of DOUBLE precision values and of length "(2*hsize) + 1" pixels 
;   representing the required Gaussian profile. If the function fails, then it returns a value of "0.0".
;
; Author: Dan Bramich (dmb@ing.iac.es)
;
; History:
;
;   17/07/2008 - Module created (dmb)

;Force the half size of the output pixel vector to be at least zero

;Check the parameters "fwhm" and "x0"

;Force the oversampling factor to be at least 1, and limit its maximum value to 10

;Convert the Gaussian FWHM to a Gaussian sigma

;Generate the coordinate vector for the oversampled pixel vector

;Calculate the values of the Gaussian profile for the oversampled pixel vector

;Bin the oversampled pixel vector by the oversampling factor "hires"

;Normalise the output pixel vector to a peak value of 1

;Return the output pixel vector representing the Gaussian profile