SMOOTH is an intrinsic IDL function that does an ``N''-point smooth of ``FLUX''. You may define a variable to be the smoothed array (e.g, fs=smooth(f,5)), or it may be used directly (e.g., plot,w,smooth(f,5)). Note that F may have either 1 or 2 dimensions.
FILTER smooths with a symmetric filter. If ``FILTR'' is a scalar, the data will be smoothed by a boxcar of width ``FILTR''. If ``FILTR'' is a vector, FILTR(0) is the center of the filter, e.g., for a five point triangular filter: FILTR=[3.0,2.0,1.0]. The filtered fluxes are returned in FF. F must be one dimensional.
GFILTER applies an NPT-point gaussian filter, where the gaussian curve has a width of SIG. Results are returned in FG. Note that F may have 1, 2, or 3 dimensions.