Beispiel #1
0
def test_sasuke():
    # Read the data
    specfile = data_test_file('MaNGA_test_spectra.fits.gz')
    hdu = fits.open(specfile)
    drpbm = DRPFitsBitMask()
    flux = numpy.ma.MaskedArray(hdu['FLUX'].data,
                                mask=drpbm.flagged(
                                    hdu['MASK'].data,
                                    MaNGADataCube.do_not_fit_flags()))
    ferr = numpy.ma.power(hdu['IVAR'].data, -0.5)
    flux[ferr.mask] = numpy.ma.masked
    ferr[flux.mask] = numpy.ma.masked
    nspec = flux.shape[0]

    # Instantiate the template libary
    velscale_ratio = 4
    tpl = TemplateLibrary('MILESHC',
                          match_resolution=False,
                          velscale_ratio=velscale_ratio,
                          spectral_step=1e-4,
                          log=True,
                          hardcopy=False)
    tpl_sres = numpy.mean(tpl['SPECRES'].data, axis=0)

    # Get the pixel mask
    pixelmask = SpectralPixelMask(artdb=ArtifactDB.from_key('BADSKY'),
                                  emldb=EmissionLineDB.from_key('ELPSCMSK'))

    # Instantiate the fitting class
    ppxf = PPXFFit(StellarContinuumModelBitMask())

    # Perform the fit
    sc_wave, sc_flux, sc_mask, sc_par \
        = ppxf.fit(tpl['WAVE'].data.copy(), tpl['FLUX'].data.copy(), hdu['WAVE'].data, flux, ferr,
                   hdu['Z'].data, numpy.full(nspec, 100.), iteration_mode='no_global_wrej',
                   reject_boxcar=100, ensemble=False, velscale_ratio=velscale_ratio,
                   mask=pixelmask, matched_resolution=False, tpl_sres=tpl_sres,
                   obj_sres=hdu['SRES'].data, degree=8, moments=2)

    # Mask the 5577 sky line
    pixelmask = SpectralPixelMask(artdb=ArtifactDB.from_key('BADSKY'))

    # Read the emission line fitting database
    emldb = EmissionLineDB.from_key('ELPMILES')
    assert emldb['name'][
        18] == 'Ha', 'Emission-line database names or ordering changed'

    # Instantiate the fitting class
    emlfit = Sasuke(EmissionLineModelBitMask())

    # Perform the fit
    el_wave, model, el_flux, el_mask, el_fit, el_par \
            = emlfit.fit(emldb, hdu['WAVE'].data, flux, obj_ferr=ferr, obj_mask=pixelmask,
                         obj_sres=hdu['SRES'].data, guess_redshift=hdu['Z'].data,
                         guess_dispersion=numpy.full(nspec, 100.), reject_boxcar=101,
                         stpl_wave=tpl['WAVE'].data, stpl_flux=tpl['FLUX'].data,
                         stpl_sres=tpl_sres, stellar_kinematics=sc_par['KIN'],
                         etpl_sinst_mode='offset', etpl_sinst_min=10.,
                         velscale_ratio=velscale_ratio, matched_resolution=False)

    # Rejected pixels
    assert numpy.sum(emlfit.bitmask.flagged(el_mask, flag='PPXF_REJECT')) == 266, \
                'Different number of rejected pixels'

    # Unable to fit
    assert numpy.array_equal(emlfit.bitmask.flagged_bits(el_fit['MASK'][5]), ['NO_FIT']), \
                'Expected NO_FIT in 6th spectrum'

    # No *attempted* fits should fail
    assert numpy.sum(emlfit.bitmask.flagged(el_fit['MASK'], flag='FIT_FAILED')) == 0, \
                'Fits should not fail'

    # Number of used templates
    assert numpy.array_equal(numpy.sum(numpy.absolute(el_fit['TPLWGT']) > 1e-10, axis=1),
                             [25, 22, 34, 32, 27,  0, 16, 22]), \
                'Different number of templates with non-zero weights'

    # No additive coefficients
    assert numpy.all(el_fit['ADDCOEF'] == 0), \
                'No additive coefficients should exist'

    # No multiplicative coefficients
    assert numpy.all(el_fit['MULTCOEF'] == 0), \
                'No multiplicative coefficients should exist'

    # Fit statistics
    assert numpy.all(
        numpy.absolute(
            el_fit['RCHI2'] -
            numpy.array([2.34, 1.22, 1.58, 1.88, 3.20, 0., 1.05, 0.88])) < 0.02
    ), 'Reduced chi-square are too different'

    assert numpy.all(
        numpy.absolute(el_fit['RMS'] - numpy.array(
            [0.036, 0.019, 0.036, 0.024, 0.051, 0.000, 0.012, 0.012])) < 0.001
    ), 'RMS too different'

    assert numpy.all(numpy.absolute(el_fit['FRMS'] -
                                    numpy.array([0.021, 0.025, 0.025, 0.033, 0.018, 0.000,
                                                 1.052, 0.101])) < 0.001), \
            'Fractional RMS too different'

    assert numpy.all(numpy.absolute(el_fit['RMSGRW'][:,2] -
                                    numpy.array([0.070, 0.038, 0.071, 0.047, 0.101, 0.000, 0.026,
                                                 0.024])) < 0.001), \
            'Median absolute residual too different'

    # All lines should have the same velocity
    assert numpy.all(numpy.all(el_par['KIN'][:,:,0] == el_par['KIN'][:,None,0,0], axis=1)), \
                'All velocities should be the same'

    # Test velocity values
    # TODO: Need some better examples!
    assert numpy.all(numpy.absolute(el_par['KIN'][:,0,0] -
                                    numpy.array([14704.9, 14869.3, 14767.1, 8161.9, 9258.7, 0.0,
                                                  5130.9,  5430.3])) < 0.1), \
                'Velocities are too different'

    # H-alpha dispersions
    assert numpy.all(numpy.absolute(el_par['KIN'][:,18,1] -
                                    numpy.array([1000.5, 1000.5, 224.7, 124.9, 171.2, 0.0, 81.2,
                                                   50.0])) < 1e-1), \
            'H-alpha dispersions are too different'
Beispiel #2
0
        el_tpl = TemplateLibrary(el_tpl_key, sres=_sres, velscale_ratio=velscale_ratio,
                                 spectral_step=1e-4, log=True, hardcopy=False)
        el_tpl_sres = numpy.mean(el_tpl['SPECRES'].data, axis=0).ravel()
        # ... and use the corrected velocity dispersions.
        stellar_kinematics = cont_par['KIN']
        stellar_kinematics[:,1] = numpy.ma.sqrt(numpy.square(cont_par['KIN'][:,1]) -
                                                    numpy.square(cont_par['SIGMACORR_EMP']))
    
    # Mask the 5577 sky line
    el_pixel_mask = SpectralPixelMask(artdb=ArtifactDB.from_key('BADSKY'))

    # Read the emission line fitting database
    emldb = EmissionLineDB.from_key(elfit_key)

    # Instantiate the fitting class
    emlfit = Sasuke(EmissionLineModelBitMask())

    # Perform the emission-line fit on each spectrum using the stellar
    # kinematics from the stacked spectrum
    eml_wave, model_flux, eml_flux, eml_mask, eml_fit_par, eml_eml_par \
            = emlfit.fit(emldb, wave_binned, flux_binned, obj_ferr=ferr_binned,
                         obj_mask=el_pixel_mask, obj_sres=sres_binned,
                         guess_redshift=z_binned, guess_dispersion=dispersion_binned,
                         reject_boxcar=101, stpl_wave=el_tpl['WAVE'].data,
                         stpl_flux=el_tpl['FLUX'].data, stpl_sres=el_tpl_sres,
                         stellar_kinematics=stellar_kinematics, etpl_sinst_mode='offset',
                         etpl_sinst_min=10., velscale_ratio=velscale_ratio,
                         matched_resolution=False, mdegree=8, plot=fit_plots,
                         remapid=binid, remap_flux=flux, remap_ferr=ferr,
                         remap_mask=el_pixel_mask, remap_sres=sres, remap_skyx=x, remap_skyy=y,
                         obj_skyx=x_binned, obj_skyy=y_binned)
Beispiel #3
0
def main():
    t = time.perf_counter()
    arg = parse_args()
    if not os.path.isfile(arg.inp):
        raise FileNotFoundError('No file: {0}'.format(arg.inp))
    directory_path = os.getcwd(
    ) if arg.output_root is None else os.path.abspath(arg.output_root)
    if not os.path.isdir(directory_path):
        os.makedirs(directory_path)

    data_file = os.path.abspath(arg.inp)
    fit_file = os.path.join(directory_path, arg.out)
    flag_db = None if arg.spec_flags is None else os.path.abspath(
        arg.spec_flags)

    # Read the data
    spectral_step = 1e-4
    wave, flux, ferr, sres, redshift, fit_spectrum = object_data(
        data_file, flag_db)
    nspec, npix = flux.shape
    dispersion = numpy.full(nspec, 100., dtype=numpy.float)

    #    fit_spectrum[:] = False
    #    fit_spectrum[0] = True
    #    fit_spectrum[171] = True
    #    fit_spectrum[791] = True

    # Mask spectra that should not be fit
    indx = numpy.any(numpy.logical_not(numpy.ma.getmaskarray(flux)),
                     axis=1) & fit_spectrum
    flux[numpy.logical_not(indx), :] = numpy.ma.masked

    print('Read: {0}'.format(arg.inp))
    print('Contains {0} spectra'.format(nspec))
    print(' each with {0} pixels'.format(npix))
    print('Fitting {0} spectra.'.format(numpy.sum(fit_spectrum)))

    #-------------------------------------------------------------------
    #-------------------------------------------------------------------
    # Fit the stellar continuum

    # Construct the template library
    sc_tpl = TemplateLibrary(arg.sc_tpl,
                             match_resolution=False,
                             velscale_ratio=arg.sc_vsr,
                             spectral_step=spectral_step,
                             log=True,
                             hardcopy=False)
    # Set the spectral resolution
    sc_tpl_sres = numpy.mean(sc_tpl['SPECRES'].data, axis=0).ravel()
    # Set the pixel mask
    sc_pixel_mask = SpectralPixelMask(artdb=ArtifactDB.from_key('BADSKY'),
                                      emldb=EmissionLineDB.from_key('ELPMPL8'))
    # Instantiate the fitting class
    ppxf = PPXFFit(StellarContinuumModelBitMask())

    # The following call performs the fit to the spectrum. Specifically
    # note that the code only fits the first two moments, uses an
    # 8th-order additive polynomial, and uses the 'no_global_wrej'
    # iteration mode. See
    # https://sdss-mangadap.readthedocs.io/en/latest/api/mangadap.proc.ppxffit.html#mangadap.proc.ppxffit.PPXFFit.fit
    cont_wave, cont_flux, cont_mask, cont_par \
        = ppxf.fit(sc_tpl['WAVE'].data.copy(), sc_tpl['FLUX'].data.copy(), wave, flux, ferr,
                   redshift, dispersion, iteration_mode='no_global_wrej', reject_boxcar=100,
                   ensemble=False, velscale_ratio=arg.sc_vsr, mask=sc_pixel_mask,
                   matched_resolution=False, tpl_sres=sc_tpl_sres, obj_sres=sres,
                   degree=arg.sc_deg, moments=2) #, plot=True)

    if arg.sc_only:
        write(fit_file, wave, cont_flux, cont_mask, cont_par)
        print('Elapsed time: {0} seconds'.format(time.perf_counter() - t))
        return

#    if numpy.any(cont_par['KIN'][:,1] < 0):
#        embed()
#        exit()
#-------------------------------------------------------------------

#-------------------------------------------------------------------
#-------------------------------------------------------------------
# Measure the emission-line moments

#    # Remask the continuum fit
#    sc_continuum = StellarContinuumModel.reset_continuum_mask_window(
#                        numpy.ma.MaskedArray(cont_flux, mask=cont_mask>0))
#    # Read the database that define the emission lines and passbands
#    momdb = EmissionMomentsDB.from_key(arg.el_band)
#    # Measure the moments
#    elmom = EmissionLineMoments.measure_moments(momdb, wave, flux, continuum=sc_continuum,
#                                                redshift=redshift)
#-------------------------------------------------------------------

#-------------------------------------------------------------------
# Fit the emission-line model

# Set the emission-line continuum templates if different from those
# used for the stellar continuum
    if arg.sc_tpl == arg.el_tpl:
        # If the keywords are the same, just copy over the previous
        # library and the best fitting stellar kinematics
        el_tpl = sc_tpl
        el_tpl_sres = sc_tpl_sres
        stellar_kinematics = cont_par['KIN'].copy()
    else:
        # If the template sets are different, we need to match the
        # spectral resolution to the galaxy data and use the corrected
        # velocity dispersions.
        _sres = SpectralResolution(wave, sres[0, :], log10=True)
        el_tpl = TemplateLibrary(arg.el_tpl,
                                 sres=_sres,
                                 velscale_ratio=arg.el_vsr,
                                 spectral_step=spectral_step,
                                 log=True,
                                 hardcopy=False)
        el_tpl_sres = numpy.mean(el_tpl['SPECRES'].data, axis=0).ravel()
        stellar_kinematics = cont_par['KIN'].copy()
        stellar_kinematics[:, 1] = numpy.ma.sqrt(
            numpy.square(cont_par['KIN'][:, 1]) -
            numpy.square(cont_par['SIGMACORR_SRES'])).filled(0.0)


#    if numpy.any(cont_par['KIN'][:,1] < 0):
#        embed()
#        exit()
#
#    if numpy.any(stellar_kinematics[:,1] < 0):
#        embed()
#        exit()

# Mask the 5577 sky line
    el_pixel_mask = SpectralPixelMask(artdb=ArtifactDB.from_key('BADSKY'))

    # Read the emission line fitting database
    emldb = EmissionLineDB.from_key(arg.el_list)

    # Instantiate the fitting class
    emlfit = Sasuke(EmissionLineModelBitMask())

    # TODO: Improve the initial velocity guess using the first moment...

    # Perform the fit
    elfit_time = time.perf_counter()
    model_wave, model_flux, eml_flux, model_mask, eml_fit_par, eml_eml_par \
            = emlfit.fit(emldb, wave, flux, obj_ferr=ferr, obj_mask=el_pixel_mask, obj_sres=sres,
                         guess_redshift=redshift, guess_dispersion=dispersion, reject_boxcar=101,
                         stpl_wave=el_tpl['WAVE'].data, stpl_flux=el_tpl['FLUX'].data,
                         stpl_sres=el_tpl_sres, stellar_kinematics=stellar_kinematics,
                         etpl_sinst_mode='offset', etpl_sinst_min=10., velscale_ratio=arg.el_vsr,
                         matched_resolution=False, mdegree=arg.el_deg, ensemble=False)#, plot=True)
    print('EML FIT TIME: ', time.perf_counter() - elfit_time)

    # Line-fit metrics (should this be done in the fit method?)
    eml_eml_par = EmissionLineFit.line_metrics(emldb,
                                               wave,
                                               flux,
                                               ferr,
                                               model_flux,
                                               eml_eml_par,
                                               model_mask=model_mask,
                                               bitmask=emlfit.bitmask)

    # Equivalent widths
    EmissionLineFit.measure_equivalent_width(wave,
                                             flux,
                                             emldb,
                                             eml_eml_par,
                                             bitmask=emlfit.bitmask,
                                             checkdb=False)

    # Measure the emission-line moments
    #   - Model continuum
    continuum = StellarContinuumModel.reset_continuum_mask_window(model_flux -
                                                                  eml_flux)
    #   - Updated redshifts
    fit_redshift = eml_eml_par['KIN'][:,numpy.where(emldb['name'] == 'Ha')[0][0],0] \
                        / astropy.constants.c.to('km/s').value
    #   - Set the moment database
    momdb = EmissionMomentsDB.from_key(arg.el_band)
    #   - Set the moment bitmask
    mombm = EmissionLineMomentsBitMask()
    #   - Measure the moments
    elmom = EmissionLineMoments.measure_moments(momdb,
                                                wave,
                                                flux,
                                                ivar=numpy.ma.power(ferr, -2),
                                                continuum=continuum,
                                                redshift=fit_redshift,
                                                bitmask=mombm)
    #   - Select the bands that are valid
    include_band = numpy.array([numpy.logical_not(momdb.dummy)]*nspec) \
                        & numpy.logical_not(mombm.flagged(elmom['MASK'],
                                                          flag=['BLUE_EMPTY', 'RED_EMPTY']))
    #   - Set the line center at the center of the primary passband
    line_center = (1.0 + fit_redshift)[:, None] * momdb['restwave'][None, :]
    elmom['BMED'], elmom['RMED'], pos, elmom['EWCONT'], elmom['EW'], elmom['EWERR'] \
            = emission_line_equivalent_width(wave, flux, momdb['blueside'], momdb['redside'],
                                             line_center, elmom['FLUX'], redshift=fit_redshift,
                                             line_flux_err=elmom['FLUXERR'],
                                             include_band=include_band)
    #   - Flag non-positive measurements
    indx = include_band & numpy.logical_not(pos)
    elmom['MASK'][indx] = mombm.turn_on(elmom['MASK'][indx],
                                        'NON_POSITIVE_CONTINUUM')
    #   - Set the binids
    elmom['BINID'] = numpy.arange(nspec)
    elmom['BINID_INDEX'] = numpy.arange(nspec)

    write(fit_file,
          wave,
          cont_flux,
          cont_mask,
          cont_par,
          model_flux=model_flux,
          model_mask=model_mask,
          eml_flux=eml_flux,
          eml_fit_par=eml_fit_par,
          eml_eml_par=eml_eml_par,
          elmom=elmom)
    print('Elapsed time: {0} seconds'.format(time.perf_counter() - t))
Beispiel #4
0
                                 hardcopy=False)
        el_tpl_sres = numpy.mean(el_tpl['SPECRES'].data, axis=0).ravel()
        # ... and use the corrected velocity dispersions.
        stellar_kinematics = cont_par['KIN']
        stellar_kinematics[:, 1] = numpy.ma.sqrt(
            numpy.square(cont_par['KIN'][:, 1]) -
            numpy.square(cont_par['SIGMACORR_EMP']))

    # Mask the 5577 sky line
    el_pixel_mask = SpectralPixelMask(artdb=ArtifactDB.from_key('BADSKY'))

    # Read the emission line fitting database
    emldb = EmissionLineDB.from_key(elfit_key)

    # Instantiate the fitting class
    emlfit = Sasuke(EmissionLineModelBitMask())

    # Perform the fit
    efit_t = time.perf_counter()
    eml_wave, model_flux, eml_flux, eml_mask, eml_fit_par, eml_eml_par \
            = emlfit.fit(emldb, wave, flux, obj_ferr=ferr, obj_mask=el_pixel_mask, obj_sres=sres,
                         guess_redshift=z, guess_dispersion=dispersion, reject_boxcar=101,
                         stpl_wave=el_tpl['WAVE'].data, stpl_flux=el_tpl['FLUX'].data,
                         stpl_sres=el_tpl_sres, stellar_kinematics=stellar_kinematics,
                         etpl_sinst_mode='offset', etpl_sinst_min=10.,
                         velscale_ratio=el_velscale_ratio, matched_resolution=False, mdegree=8,
                         plot=fit_plots)
    print('TIME: ', time.perf_counter() - efit_t)

    # Line-fit metrics
    eml_eml_par = EmissionLineFit.line_metrics(emldb,
Beispiel #5
0
def main():

    t = time.perf_counter()

    #-------------------------------------------------------------------
    # Read spectra to fit. The following reads a single MaNGA spectrum.
    # This is where you should read in your own spectrum to fit.
    # Plate-IFU to use
    plt = 7815
    ifu = 3702
    # Spaxel coordinates
    x = 25 #30
    y = 25 #37
    # Where to find the relevant datacube.  This example accesses the test data
    # that can be downloaded by executing the script here:
    # https://github.com/sdss/mangadap/blob/master/download_test_data.py
    directory_path = defaults.dap_source_dir() / 'data' / 'remote'
    # Read a spectrum
    wave, flux, ivar, sres = get_spectra(plt, ifu, x, y, directory_path=directory_path)
    # In general, the DAP fitting functions expect data to be in 2D
    # arrays with shape (N-spectra,N-wave). So if you only have one
    # spectrum, you need to expand the dimensions:
    flux = flux.reshape(1,-1)
    ivar = ivar.reshape(1,-1)
    ferr = numpy.ma.power(ivar, -0.5)
    sres = sres.reshape(1,-1)

    # The majority (if not all) of the DAP methods expect that your
    # spectra are binned logarithmically in wavelength (primarily
    # because this is what pPXF expects). You can either have the DAP
    # function determine this value (commented line below) or set it
    # directly. The value is used to resample the template spectra to
    # match the sampling of the spectra to fit (up to some integer; see
    # velscale_ratio).
#    spectral_step = spectral_coordinate_step(wave, log=True)
    spectral_step = 1e-4

    # Hereafter, the methods expect a wavelength vector, a flux array
    # with the spectra to fit, an ferr array with the 1-sigma errors in
    # the flux, and sres with the wavelength-dependent spectral
    # resolution, R = lambda / Dlambda
    #-------------------------------------------------------------------

    #-------------------------------------------------------------------
    # The DAP needs a reasonable guess of the redshift of the spectrum
    # (within +/- 2000 km/s). In this example, I'm pulling the redshift
    # from the DRPall file. There must be one redshift estimate per
    # spectrum to fit.  Here that means it's a single element array
    # This example accesses the test data
    # that can be downloaded by executing the script here:
    # https://github.com/sdss/mangadap/blob/master/download_test_data.py
    drpall_file = directory_path / f'drpall-{drp_test_version}.fits'
    z = numpy.array([get_redshift(plt, ifu, drpall_file)])
    print('Redshift: {0}'.format(z[0]))
    # The DAP also requires an initial guess for the velocity
    # dispersion. A guess of 100 km/s is usually robust, but this may
    # depend on your spectral resolution.
    dispersion = numpy.array([100.])
    #-------------------------------------------------------------------

    #-------------------------------------------------------------------
    # The following sets the keyword for the template spectra to use
    # during the fit. You can specify different template sets to use
    # during the stellar-continuum (stellar kinematics) fit and the
    # emission-line modeling.

    # Templates used in the stellar continuum fits
    sc_tpl_key = 'MILESHC'
    # Templates used in the emission-line modeling
    el_tpl_key = 'MASTARSSP'

    # You also need to specify the sampling for the template spectra.
    # The templates must be sampled with the same pixel step as the
    # spectra to be fit, up to an integer factor. The critical thing
    # for the sampling is that you do not want to undersample the
    # spectral resolution element of the template spectra. Here, I set
    # the sampling for the MILES templates to be a factor of 4 smaller
    # than the MaNGA spectrum to be fit (which is a bit of overkill
    # given the resolution difference). I set the sampling of the
    # MaStar templates to be the same as the galaxy data.

    # Template pixel scale a factor of 4 smaller than galaxy data
    sc_velscale_ratio = 4
    # Template sampling is the same as the galaxy data
    el_velscale_ratio = 1

    # You then need to identify the database that defines the
    # emission-line passbands (elmom_key) for the non-parametric
    # emission-line moment calculations, and the emission-line
    # parameters (elfit_key) for the Gaussian emission-line modeling.
    # See
    # https://sdss-mangadap.readthedocs.io/en/latest/emissionlines.html.
    elmom_key = 'ELBMPL9'
    elfit_key = 'ELPMPL11'

    # If you want to also calculate the spectral indices, you can
    # provide a keyword that indicates the database with the passband
    # definitions for both the absorption-line and bandhead/color
    # indices to measure. The script allows these to be None, if you
    # don't want to calculate the spectral indices. See
    # https://sdss-mangadap.readthedocs.io/en/latest/spectralindices.html
    absindx_key = 'EXTINDX'
    bhdindx_key = 'BHBASIC'

    # Now we want to construct a pixel mask that excludes regions with
    # known artifacts and emission lines. The 'BADSKY' artifact
    # database only masks the 5577, which can have strong left-over
    # residuals after sky-subtraction. The list of emission lines (set
    # by the ELPMPL8 keyword) can be different from the list of
    # emission lines fit below.
    sc_pixel_mask = SpectralPixelMask(artdb=ArtifactDB.from_key('BADSKY'),
                                      emldb=EmissionLineDB.from_key('ELPMPL11'))
    # Mask the 5577 sky line
    el_pixel_mask = SpectralPixelMask(artdb=ArtifactDB.from_key('BADSKY'))

    # Finally, you can set whether or not to show a set of plots.
    #
    # Show the ppxf-generated plots for each fit stage.
    fit_plots = False
    # Show summary plots
    usr_plots = True
    #-------------------------------------------------------------------


    #-------------------------------------------------------------------
    # Fit the stellar continuum

    # First, we construct the template library. The keyword that
    # selects the template library (sc_tpl_key) is defined above. The
    # following call reads in the template library and processes the
    # data to have the appropriate pixel sampling. Note that *no*
    # matching of the spectral resolution to the galaxy spectrum is
    # performed.
    sc_tpl = TemplateLibrary(sc_tpl_key, match_resolution=False, velscale_ratio=sc_velscale_ratio,
                             spectral_step=spectral_step, log=True, hardcopy=False)

    # This calculation of the mean spectral resolution is a kludge. The
    # template library should provide spectra that are *all* at the
    # same spectral resolution. Otherwise, one cannot freely combine
    # the spectra to fit the Doppler broadening of the galaxy spectrum
    # in a robust (constrained) way (without substantially more
    # effort). There should be no difference between what's done below
    # and simply taking the spectral resolution to be that of the first
    # template spectrum (i.e., sc_tpl['SPECRES'].data[0])
    sc_tpl_sres = numpy.mean(sc_tpl['SPECRES'].data, axis=0).ravel()

    # Instantiate the fitting class, including the mask that it should
    # use to flag the data. [[This mask should just be default...]]
    ppxf = PPXFFit(StellarContinuumModelBitMask())

    # The following call performs the fit to the spectrum. Specifically
    # note that the code only fits the first two moments, uses an
    # 8th-order additive polynomial, and uses the 'no_global_wrej'
    # iteration mode. See
    # https://sdss-mangadap.readthedocs.io/en/latest/api/mangadap.proc.ppxffit.html#mangadap.proc.ppxffit.PPXFFit.fit
    cont_wave, cont_flux, cont_mask, cont_par \
        = ppxf.fit(sc_tpl['WAVE'].data.copy(), sc_tpl['FLUX'].data.copy(), wave, flux, ferr,
                   z, dispersion, iteration_mode='no_global_wrej', reject_boxcar=100,
                   ensemble=False, velscale_ratio=sc_velscale_ratio, mask=sc_pixel_mask,
                   matched_resolution=False, tpl_sres=sc_tpl_sres, obj_sres=sres, degree=8,
                   moments=2, plot=fit_plots)

    # The returned objects from the fit are the wavelength, model, and
    # mask vectors and the record array with the best-fitting model
    # parameters. The datamodel of the best-fitting model parameters is
    # set by:
    # https://sdss-mangadap.readthedocs.io/en/latest/api/mangadap.proc.spectralfitting.html#mangadap.proc.spectralfitting.StellarKinematicsFit._per_stellar_kinematics_dtype

    # Remask the continuum fit
    sc_continuum = StellarContinuumModel.reset_continuum_mask_window(
                        numpy.ma.MaskedArray(cont_flux, mask=cont_mask>0))

    # Show the fit and residual
    if usr_plots:
        pyplot.plot(wave, flux[0,:], label='Data')
        pyplot.plot(wave, sc_continuum[0,:], label='Model')
        pyplot.plot(wave, flux[0,:] - sc_continuum[0,:], label='Resid')
        pyplot.legend()
        pyplot.xlabel('Wavelength')
        pyplot.ylabel('Flux')
        pyplot.show()
    #-------------------------------------------------------------------

    #-------------------------------------------------------------------
    # Get the emission-line moments using the fitted stellar continuum

    # Read the database that define the emission lines and passbands
    momdb = EmissionMomentsDB.from_key(elmom_key)

    # Measure the moments
    elmom = EmissionLineMoments.measure_moments(momdb, wave, flux, continuum=sc_continuum,
                                                redshift=z)
    #-------------------------------------------------------------------

    #-------------------------------------------------------------------
    # Fit the emission-line model

    # Set the emission-line continuum templates if different from those
    # used for the stellar continuum
    if sc_tpl_key == el_tpl_key:
        # If the keywords are the same, just copy over the previous
        # library ...
        el_tpl = sc_tpl
        el_tpl_sres = sc_tpl_sres
        # ... and the best fitting stellar kinematics
        stellar_kinematics = cont_par['KIN']
    else:
        # If the template sets are different, we need to match the
        # spectral resolution to the galaxy data ...
        _sres = SpectralResolution(wave, sres[0,:], log10=True)
        el_tpl = TemplateLibrary(el_tpl_key, sres=_sres, velscale_ratio=el_velscale_ratio,
                                 spectral_step=spectral_step, log=True, hardcopy=False)
        el_tpl_sres = numpy.mean(el_tpl['SPECRES'].data, axis=0).ravel()
        # ... and use the corrected velocity dispersions.
        stellar_kinematics = cont_par['KIN']
        stellar_kinematics[:,1] = numpy.ma.sqrt(numpy.square(cont_par['KIN'][:,1]) -
                                                    numpy.square(cont_par['SIGMACORR_EMP']))

    # Read the emission line fitting database
    emldb = EmissionLineDB.from_key(elfit_key)

    # Instantiate the fitting class
    emlfit = Sasuke(EmissionLineModelBitMask())

    # Perform the fit
    efit_t = time.perf_counter()
    eml_wave, model_flux, eml_flux, eml_mask, eml_fit_par, eml_eml_par \
            = emlfit.fit(emldb, wave, flux, obj_ferr=ferr, obj_mask=el_pixel_mask, obj_sres=sres,
                         guess_redshift=z, guess_dispersion=dispersion, reject_boxcar=101,
                         stpl_wave=el_tpl['WAVE'].data, stpl_flux=el_tpl['FLUX'].data,
                         stpl_sres=el_tpl_sres, stellar_kinematics=stellar_kinematics,
                         etpl_sinst_mode='offset', etpl_sinst_min=10.,
                         velscale_ratio=el_velscale_ratio, matched_resolution=False, mdegree=8,
                         plot=fit_plots)
    print('TIME: ', time.perf_counter() - efit_t)

    # Line-fit metrics
    eml_eml_par = EmissionLineFit.line_metrics(emldb, wave, flux, ferr, model_flux, eml_eml_par,
                                               model_mask=eml_mask, bitmask=emlfit.bitmask)

    # Get the stellar continuum that was fit for the emission lines
    elcmask = eml_mask.ravel() > 0
    goodpix = numpy.arange(elcmask.size)[numpy.invert(elcmask)]
    start, end = goodpix[0], goodpix[-1]+1
    elcmask[start:end] = False
    el_continuum = numpy.ma.MaskedArray(model_flux - eml_flux,
                                        mask=elcmask.reshape(model_flux.shape))

    # Plot the result
    if usr_plots:
        pyplot.plot(wave, flux[0,:], label='Data')
        pyplot.plot(wave, model_flux[0,:], label='Model')
        pyplot.plot(wave, el_continuum[0,:], label='EL Cont.')
        pyplot.plot(wave, sc_continuum[0,:], label='SC Cont.')
        pyplot.legend()
        pyplot.xlabel('Wavelength')
        pyplot.ylabel('Flux')
        pyplot.show()

    # Remeasure the emission-line moments with the new continuum
    new_elmom = EmissionLineMoments.measure_moments(momdb, wave, flux, continuum=el_continuum,
                                                    redshift=z)

    # Compare the summed flux and Gaussian-fitted flux for all the
    # fitted lines
    if usr_plots:
        pyplot.scatter(emldb['restwave'], (new_elmom['FLUX']-eml_eml_par['FLUX']).ravel(),
                       c=eml_eml_par['FLUX'].ravel(), cmap='viridis', marker='.', s=60, lw=0,
                       zorder=4)
        pyplot.grid()
        pyplot.xlabel('Wavelength')
        pyplot.ylabel('Summed-Gaussian Difference')
        pyplot.show()
    #-------------------------------------------------------------------

    #-------------------------------------------------------------------
    # Measure the spectral indices
    if absindx_key is None or bhdindx_key is None:
        # Neither are defined, so we're done
        print('Elapsed time: {0} seconds'.format(time.perf_counter() - t))
        return

    # Setup the databases that define the indices to measure
    absdb = None if absindx_key is None else AbsorptionIndexDB.from_key(absindx_key)
    bhddb = None if bhdindx_key is None else BandheadIndexDB.from_key(bhdindx_key)

    # Remove the modeled emission lines from the spectra
    flux_noeml = flux - eml_flux
    redshift = stellar_kinematics[:,0] / astropy.constants.c.to('km/s').value
    sp_indices = SpectralIndices.measure_indices(absdb, bhddb, wave, flux_noeml, ivar=ivar,
                                                 redshift=redshift)

    # Calculate the velocity dispersion corrections
    #   - Construct versions of the best-fitting model spectra with and without
    #     the included dispersion
    continuum = Sasuke.construct_continuum_models(emldb, el_tpl['WAVE'].data, el_tpl['FLUX'].data,
                                                  wave, flux.shape, eml_fit_par)
    continuum_dcnvlv = Sasuke.construct_continuum_models(emldb, el_tpl['WAVE'].data,
                                                         el_tpl['FLUX'].data, wave, flux.shape,
                                                         eml_fit_par, redshift_only=True)

    #   - Get the dispersion corrections and fill the relevant columns of the
    #     index table
    sp_indices['BCONT_MOD'], sp_indices['BCONT_CORR'], sp_indices['RCONT_MOD'], \
        sp_indices['RCONT_CORR'], sp_indices['MCONT_MOD'], sp_indices['MCONT_CORR'], \
        sp_indices['AWGT_MOD'], sp_indices['AWGT_CORR'], \
        sp_indices['INDX_MOD'], sp_indices['INDX_CORR'], \
        sp_indices['INDX_BF_MOD'], sp_indices['INDX_BF_CORR'], \
        good_les, good_ang, good_mag, is_abs \
                = SpectralIndices.calculate_dispersion_corrections(absdb, bhddb, wave, flux,
                                                                   continuum, continuum_dcnvlv,
                                                                   redshift=redshift,
                                                                   redshift_dcnvlv=redshift)

    # Apply the index corrections.  This is only done here for the
    # Worthey/Trager definition of the indices, as an example
    corrected_indices = numpy.zeros(sp_indices['INDX'].shape, dtype=float)
    corrected_indices_err = numpy.zeros(sp_indices['INDX'].shape, dtype=float)
    # Unitless indices
    corrected_indices[good_les], corrected_indices_err[good_les] \
            = SpectralIndices.apply_dispersion_corrections(sp_indices['INDX'][good_les],
                                                           sp_indices['INDX_CORR'][good_les],
                                                           err=sp_indices['INDX_ERR'][good_les])
    # Indices in angstroms
    corrected_indices[good_ang], corrected_indices_err[good_ang] \
            = SpectralIndices.apply_dispersion_corrections(sp_indices['INDX'][good_ang],
                                                           sp_indices['INDX_CORR'][good_ang],
                                                           err=sp_indices['INDX_ERR'][good_ang],
                                                           unit='ang')
    # Indices in magnitudes
    corrected_indices[good_mag], corrected_indices_err[good_mag] \
            = SpectralIndices.apply_dispersion_corrections(sp_indices['INDX'][good_mag],
                                                           sp_indices['INDX_CORR'][good_mag],
                                                           err=sp_indices['INDX_ERR'][good_mag],
                                                           unit='mag')

    # Print the results for a few indices
    index_names = numpy.append(absdb['name'], bhddb['name'])
    print('-'*73)
    print(f'{"NAME":<8} {"Raw Index":>12} {"err":>12} {"Index Corr":>12} {"Index":>12} {"err":>12}')
    print(f'{"-"*8:<8} {"-"*12:<12} {"-"*12:<12} {"-"*12:<12} {"-"*12:<12} {"-"*12:<12}')
    for name in ['Hb', 'HDeltaA', 'Mgb', 'Dn4000']:
        i = numpy.where(index_names == name)[0][0]
        print(f'{name:<8} {sp_indices["INDX"][0,i]:12.4f} {sp_indices["INDX_ERR"][0,i]:12.4f} '
              f'{sp_indices["INDX_CORR"][0,i]:12.4f} {corrected_indices[0,i]:12.4f} '
              f'{corrected_indices_err[0,i]:12.4f}')
    print('-'*73)

    embed()

    print('Elapsed time: {0} seconds'.format(time.perf_counter() - t))