# Par files define the parameters to be used to set a number of
# mangadap.par.emissionlinedb.EmissionLinePar objects.  Columns in the
# emission-line database parameter files are:
#
#   INDEX:
#       Unique integer identifier of the emission line.  Used when tying
#       lines together.
#   NAME:
#       Name of the element, read as a string.
#   LAMBDA:
#       Rest frame wavelength of the emission line to fit; can be in air
#       or vacuum.  DAP assumes the input is in VACUUM if not specified
#       in the definition of the database using
#       :class:`EmissionLineDBDef`
#   WAVEREF:
#       Set the reference frame of the wavelengths provided to be in
#       either air or vacuum using the keywords 'air' or 'vac',
#       respectively.
#   ACTION:
#       Describes how the line should be treated.  Possible values are:
#
#           'i': ignore the line, as if the line were commented out.
#
#           'f': fit the line and mask the line when fitting the stellar
#                continuum.
#
#           'm': mask the line when fitting the stellar continuum but do
#                NOT fit the line itself
#
#           's': defines a sky line that should be masked.  When masked,
#                the wavelength of the line is NOT adjusted for the
#                redshift of the object spectrum.
#   RELATIVE_FLUX:
#       RELATIVE flux of the emission (positive) or absorption
#       (negative) lines.  This should most often be unity when the flux
#       is not tied to another line; see 'MODE'.
#   MODE:
#       Fitting mode for the line.  Possible values are:
#
#           'f': Fit the line independently of all others in its own
#           window.
#
#           'wN': Fit the line with untied parameters, but use a window
#           that includes both this line and the line with index N.
#
#           'xN': Fit the line with its flux tied to the line with index
#           N.
#
#           'vN': Fit the line with the velocity tied to the line with
#           index N.
#
#           'sN': Fit the line with the velocity dispersion tied to the
#           line with index N.
#
#           'kN': Fit the line with the velocity and velocity dispersion
#           tied to the line with index N.
#
#           'aN': Fit the line with the flux, velocity, and velocity
#           dispersion tied to the line with index N.
#
#   PROFILE:
#       The name of the class used to construct the line profile.  The
#       available options are any of the classes in
#       mangadap.util.lineprofiles.  This functionality should likely be
#       deprecated, and the lineprofile should essentially always be
#       "FFTGaussianLSF".
#
#   NCOMP:
#       The number of components to fit.  THIS IS NEVER USED!
#
#   OUTPUT_MODEL:
#       Flag to include the best-fitting model of the line in the
#       emission-line model spectrum.  THIS IS NEVER USED!
#
#   PAR:
#       A list of the initial guess for the line profile parameters.
#       The number of parameters must match the struct declaration at
#       the top of the file.  The initial parameters are automatically
#       adjusted to provide any designated flux ratios, and the center
#       is automatically adjusted to the provided redshift for the
#       spectrum.  For example, for a GaussianLineProfile, this is
#       typically set to "{1.0 0.0 100.0}".
#   FIX:
#       A list of flags for fixing the input guess parameters during the
#       fit.  Use 0 for a free parameter, 1 for a fixed parameter.  The
#       parameter value is only fixed *AFTER* adjusted in the flux and
#       or center based on the redshift and the implied tied parameters.
#       For a free set of parameters using a GaussianLineProfile, this
#       is set to "{ 0 0 0 }".
#   LOWER_BOUND:
#       A list of lower bounds for the parameters.  For each parameter,
#       use None to indicate no lower bound.  For a GaussianLineProfile
#       with positive flux and standard deviation, this is set to
#       '{ 0.0 None 0.0 }'.
#   UPPER_BOUND:
#       A list of upper bounds for the parameters.  For each parameter,
#       use None to indicate no upper bound.  For a GaussianLineProfile
#       with maximum standard deviation of 800 km/s, this is set to
#       '{ None None 800.0 }'.
#   LOG_BOUND:
#       A list of flags used when determining if a fit parameter is near
#       the imposed boundary.  If true, the fraction of the boundary
#       range used is done in logarithmic, not linear, separation.  Use
#       0 for False, 1 for True.
#   BLUESIDE:   
#       A two-element vector with the starting and ending wavelength for
#       a bandpass blueward of the emission line, which is used to set
#       the continuum level near the emission line when calculating the
#       equivalent width.
#   REDSIDE:   
#       A two-element vector with the starting and ending wavelength for
#       a bandpass redward of the emission line, which is used to set
#       the continuum level near the emission line when calculating the
#       equivalent width.
#------------------------------------------------------------------------
