NAME: sigratio PURPOSE: Compute the relative signal level between a set of spectra (1-d vectors). DESCRIPTION: CATEGORY: Spectroscopy CALLING SEQUENCE: sigratio,stack,relsig,noise,REF=ref INPUTS: stack - an array of spectra [npts,nspec] OPTIONAL INPUT PARAMETERS: KEYWORD INPUT PARAMETERS: BAD - Array of flags for each point in stack. 0=good, 1=bad. (default=0). REF - If provided, the relative signal levels are measure relative to this spectrum out of the stack. You can also provide an external spectrum as a vector with npts. RBAD - Bad value flags for the reference (only used if REF is a spectrum). SCALE - range of pixels to use for scaling all spectra to each other. The default is to use all pixels for scaling. OUTPUTS: relsig - Output array, NSPEC long, that has the relative signal levels. noise - Output array, NSPEC long, that is the noise level in each spectrum relative to the reference. KEYWORD OUTPUT PARAMETERS: COMMON BLOCKS: SIDE EFFECTS: RESTRICTIONS: PROCEDURE: MODIFICATION HISTORY: 98/07/24 - Written by Marc W. Buie, Lowell Observatory 98/08/14, MWB, added REF spectrum support, RBAD keyword, and noise output. 98/09/10, MWB, cleanup to eliminate illegal floating point operations.