示例#1
0
def main(args):

    # Set up the logger
    if args.verbose:
        log = get_logger(DEBUG)
    else:
        log = get_logger()

    # Make sure all necessary environment variables are set
    DESI_SPECTRO_REDUX_DIR = "./quickGen"

    if 'DESI_SPECTRO_REDUX' not in os.environ:

        log.info('DESI_SPECTRO_REDUX environment is not set.')

    else:
        DESI_SPECTRO_REDUX_DIR = os.environ['DESI_SPECTRO_REDUX']

    if os.path.exists(DESI_SPECTRO_REDUX_DIR):

        if not os.path.isdir(DESI_SPECTRO_REDUX_DIR):
            raise RuntimeError("Path %s Not a directory" %
                               DESI_SPECTRO_REDUX_DIR)
    else:
        try:
            os.makedirs(DESI_SPECTRO_REDUX_DIR)
        except:
            raise

    SPECPROD_DIR = 'specprod'
    if 'SPECPROD' not in os.environ:
        log.info('SPECPROD environment is not set.')
    else:
        SPECPROD_DIR = os.environ['SPECPROD']
    prod_Dir = specprod_root()

    if os.path.exists(prod_Dir):

        if not os.path.isdir(prod_Dir):
            raise RuntimeError("Path %s Not a directory" % prod_Dir)
    else:
        try:
            os.makedirs(prod_Dir)
        except:
            raise

    # Initialize random number generator to use.
    np.random.seed(args.seed)
    random_state = np.random.RandomState(args.seed)

    # Derive spectrograph number from nstart if needed
    if args.spectrograph is None:
        args.spectrograph = args.nstart / 500

    # Read fibermapfile to get object type, night and expid
    if args.fibermap:
        log.info("Reading fibermap file {}".format(args.fibermap))
        fibermap = read_fibermap(args.fibermap)
        objtype = get_source_types(fibermap)
        stdindx = np.where(objtype == 'STD')  # match STD with STAR
        mwsindx = np.where(objtype == 'MWS_STAR')  # match MWS_STAR with STAR
        bgsindx = np.where(objtype == 'BGS')  # match BGS with LRG
        objtype[stdindx] = 'STAR'
        objtype[mwsindx] = 'STAR'
        objtype[bgsindx] = 'LRG'
        NIGHT = fibermap.meta['NIGHT']
        EXPID = fibermap.meta['EXPID']
    else:
        # Create a blank fake fibermap
        fibermap = empty_fibermap(args.nspec)
        targetids = random_state.randint(2**62, size=args.nspec)
        fibermap['TARGETID'] = targetids
        night = get_night()
        expid = 0

    log.info("Initializing SpecSim with config {}".format(args.config))
    desiparams = load_desiparams()
    qsim = get_simulator(args.config, num_fibers=1)

    if args.simspec:
        # Read the input file
        log.info('Reading input file {}'.format(args.simspec))
        simspec = desisim.io.read_simspec(args.simspec)
        nspec = simspec.nspec
        if simspec.flavor == 'arc':
            log.warning("quickgen doesn't generate flavor=arc outputs")
            return
        else:
            wavelengths = simspec.wave
            spectra = simspec.flux
        if nspec < args.nspec:
            log.info("Only {} spectra in input file".format(nspec))
            args.nspec = nspec

    else:
        # Initialize the output truth table.
        spectra = []
        wavelengths = qsim.source.wavelength_out.to(u.Angstrom).value
        npix = len(wavelengths)
        truth = dict()
        meta = Table()
        truth['OBJTYPE'] = np.zeros(args.nspec, dtype=(str, 10))
        truth['FLUX'] = np.zeros((args.nspec, npix))
        truth['WAVE'] = wavelengths
        jj = list()

        for thisobj in set(true_objtype):
            ii = np.where(true_objtype == thisobj)[0]
            nobj = len(ii)
            truth['OBJTYPE'][ii] = thisobj
            log.info('Generating {} template'.format(thisobj))

            # Generate the templates
            if thisobj == 'ELG':
                elg = desisim.templates.ELG(wave=wavelengths,
                                            add_SNeIa=args.add_SNeIa)
                flux, tmpwave, meta1 = elg.make_templates(
                    nmodel=nobj,
                    seed=args.seed,
                    zrange=args.zrange_elg,
                    sne_rfluxratiorange=args.sne_rfluxratiorange)
            elif thisobj == 'LRG':
                lrg = desisim.templates.LRG(wave=wavelengths,
                                            add_SNeIa=args.add_SNeIa)
                flux, tmpwave, meta1 = lrg.make_templates(
                    nmodel=nobj,
                    seed=args.seed,
                    zrange=args.zrange_lrg,
                    sne_rfluxratiorange=args.sne_rfluxratiorange)
            elif thisobj == 'QSO':
                qso = desisim.templates.QSO(wave=wavelengths)
                flux, tmpwave, meta1 = qso.make_templates(
                    nmodel=nobj, seed=args.seed, zrange=args.zrange_qso)
            elif thisobj == 'BGS':
                bgs = desisim.templates.BGS(wave=wavelengths,
                                            add_SNeIa=args.add_SNeIa)
                flux, tmpwave, meta1 = bgs.make_templates(
                    nmodel=nobj,
                    seed=args.seed,
                    zrange=args.zrange_bgs,
                    rmagrange=args.rmagrange_bgs,
                    sne_rfluxratiorange=args.sne_rfluxratiorange)
            elif thisobj == 'STD':
                std = desisim.templates.STD(wave=wavelengths)
                flux, tmpwave, meta1 = std.make_templates(nmodel=nobj,
                                                          seed=args.seed)
            elif thisobj == 'QSO_BAD':  # use STAR template no color cuts
                star = desisim.templates.STAR(wave=wavelengths)
                flux, tmpwave, meta1 = star.make_templates(nmodel=nobj,
                                                           seed=args.seed)
            elif thisobj == 'MWS_STAR' or thisobj == 'MWS':
                mwsstar = desisim.templates.MWS_STAR(wave=wavelengths)
                flux, tmpwave, meta1 = mwsstar.make_templates(nmodel=nobj,
                                                              seed=args.seed)
            elif thisobj == 'WD':
                wd = desisim.templates.WD(wave=wavelengths)
                flux, tmpwave, meta1 = wd.make_templates(nmodel=nobj,
                                                         seed=args.seed)
            elif thisobj == 'SKY':
                flux = np.zeros((nobj, npix))
                meta1 = Table(dict(REDSHIFT=np.zeros(nobj, dtype=np.float32)))
            elif thisobj == 'TEST':
                flux = np.zeros((args.nspec, npix))
                indx = np.where(wave > 5800.0 - 1E-6)[0][0]
                ref_integrated_flux = 1E-10
                ref_cst_flux_density = 1E-17
                single_line = (np.arange(args.nspec) % 2 == 0).astype(
                    np.float32)
                continuum = (np.arange(args.nspec) % 2 == 1).astype(np.float32)

                for spec in range(args.nspec):
                    flux[spec, indx] = single_line[
                        spec] * ref_integrated_flux / np.gradient(wavelengths)[
                            indx]  # single line
                    flux[spec] += continuum[
                        spec] * ref_cst_flux_density  # flat continuum

                meta1 = Table(
                    dict(REDSHIFT=np.zeros(args.nspec, dtype=np.float32),
                         LINE=wave[indx] *
                         np.ones(args.nspec, dtype=np.float32),
                         LINEFLUX=single_line * ref_integrated_flux,
                         CONSTFLUXDENSITY=continuum * ref_cst_flux_density))
            else:
                log.fatal('Unknown object type {}'.format(thisobj))
                sys.exit(1)

            # Pack it in.
            truth['FLUX'][ii] = flux
            meta = vstack([meta, meta1])
            jj.append(ii.tolist())

            # Sanity check on units; templates currently return ergs, not 1e-17 ergs...
            # assert (thisobj == 'SKY') or (np.max(truth['FLUX']) < 1e-6)

        # Sort the metadata table.
        jj = sum(jj, [])
        meta_new = Table()
        for k in range(args.nspec):
            index = int(np.where(np.array(jj) == k)[0])
            meta_new = vstack([meta_new, meta[index]])
        meta = meta_new

        # Add TARGETID and the true OBJTYPE to the metadata table.
        meta.add_column(
            Column(true_objtype, dtype=(str, 10), name='TRUE_OBJTYPE'))
        meta.add_column(Column(targetids, name='TARGETID'))

        # Rename REDSHIFT -> TRUEZ anticipating later table joins with zbest.Z
        meta.rename_column('REDSHIFT', 'TRUEZ')

    # explicitly set location on focal plane if needed to support airmass
    # variations when using specsim v0.5
    if qsim.source.focal_xy is None:
        qsim.source.focal_xy = (u.Quantity(0, 'mm'), u.Quantity(100, 'mm'))

    # Set simulation parameters from the simspec header or desiparams
    bright_objects = ['bgs', 'mws', 'bright', 'BGS', 'MWS', 'BRIGHT_MIX']
    gray_objects = ['gray', 'grey']
    if args.simspec is None:
        object_type = objtype
        flavor = None
    elif simspec.flavor == 'science':
        object_type = None
        flavor = simspec.header['PROGRAM']
    else:
        object_type = None
        flavor = simspec.flavor
        log.warning(
            'Maybe using an outdated simspec file with flavor={}'.format(
                flavor))

    # Set airmass
    if args.airmass is not None:
        qsim.atmosphere.airmass = args.airmass
    elif args.simspec and 'AIRMASS' in simspec.header:
        qsim.atmosphere.airmass = simspec.header['AIRMASS']
    else:
        qsim.atmosphere.airmass = 1.25  # Science Req. Doc L3.3.2

    # Set exptime
    if args.exptime is not None:
        qsim.observation.exposure_time = args.exptime * u.s
    elif args.simspec and 'EXPTIME' in simspec.header:
        qsim.observation.exposure_time = simspec.header['EXPTIME'] * u.s
    elif objtype in bright_objects:
        qsim.observation.exposure_time = desiparams['exptime_bright'] * u.s
    else:
        qsim.observation.exposure_time = desiparams['exptime_dark'] * u.s

    # Set Moon Phase
    if args.moon_phase is not None:
        qsim.atmosphere.moon.moon_phase = args.moon_phase
    elif args.simspec and 'MOONFRAC' in simspec.header:
        qsim.atmosphere.moon.moon_phase = simspec.header['MOONFRAC']
    elif flavor in bright_objects or object_type in bright_objects:
        qsim.atmosphere.moon.moon_phase = 0.7
    elif flavor in gray_objects:
        qsim.atmosphere.moon.moon_phase = 0.1
    else:
        qsim.atmosphere.moon.moon_phase = 0.5

    # Set Moon Zenith
    if args.moon_zenith is not None:
        qsim.atmosphere.moon.moon_zenith = args.moon_zenith * u.deg
    elif args.simspec and 'MOONALT' in simspec.header:
        qsim.atmosphere.moon.moon_zenith = simspec.header['MOONALT'] * u.deg
    elif flavor in bright_objects or object_type in bright_objects:
        qsim.atmosphere.moon.moon_zenith = 30 * u.deg
    elif flavor in gray_objects:
        qsim.atmosphere.moon.moon_zenith = 80 * u.deg
    else:
        qsim.atmosphere.moon.moon_zenith = 100 * u.deg

    # Set Moon - Object Angle
    if args.moon_angle is not None:
        qsim.atmosphere.moon.separation_angle = args.moon_angle * u.deg
    elif args.simspec and 'MOONSEP' in simspec.header:
        qsim.atmosphere.moon.separation_angle = simspec.header[
            'MOONSEP'] * u.deg
    elif flavor in bright_objects or object_type in bright_objects:
        qsim.atmosphere.moon.separation_angle = 50 * u.deg
    elif flavor in gray_objects:
        qsim.atmosphere.moon.separation_angle = 60 * u.deg
    else:
        qsim.atmosphere.moon.separation_angle = 60 * u.deg

    # Initialize per-camera output arrays that will be saved
    waves, trueflux, noisyflux, obsivar, resolution, sflux = {}, {}, {}, {}, {}, {}

    maxbin = 0
    nmax = args.nspec
    for camera in qsim.instrument.cameras:
        # Lookup this camera's resolution matrix and convert to the sparse
        # format used in desispec.
        R = Resolution(camera.get_output_resolution_matrix())
        resolution[camera.name] = np.tile(R.to_fits_array(),
                                          [args.nspec, 1, 1])
        waves[camera.name] = (camera.output_wavelength.to(
            u.Angstrom).value.astype(np.float32))
        nwave = len(waves[camera.name])
        maxbin = max(maxbin, len(waves[camera.name]))
        nobj = np.zeros((nmax, 3, maxbin))  # object photons
        nsky = np.zeros((nmax, 3, maxbin))  # sky photons
        nivar = np.zeros((nmax, 3, maxbin))  # inverse variance (object+sky)
        cframe_observedflux = np.zeros(
            (nmax, 3, maxbin))  # calibrated object flux
        cframe_ivar = np.zeros(
            (nmax, 3, maxbin))  # inverse variance of calibrated object flux
        cframe_rand_noise = np.zeros(
            (nmax, 3, maxbin))  # random Gaussian noise to calibrated flux
        sky_ivar = np.zeros((nmax, 3, maxbin))  # inverse variance of sky
        sky_rand_noise = np.zeros(
            (nmax, 3, maxbin))  # random Gaussian noise to sky only
        frame_rand_noise = np.zeros(
            (nmax, 3, maxbin))  # random Gaussian noise to nobj+nsky
        trueflux[camera.name] = np.empty(
            (args.nspec, nwave))  # calibrated flux
        noisyflux[camera.name] = np.empty(
            (args.nspec, nwave))  # observed flux with noise
        obsivar[camera.name] = np.empty(
            (args.nspec, nwave))  # inverse variance of flux
        if args.simspec:
            for i in range(10):
                cn = camera.name + str(i)
                if cn in simspec.cameras:
                    dw = np.gradient(simspec.cameras[cn].wave)
                    break
            else:
                raise RuntimeError(
                    'Unable to find a {} camera in input simspec'.format(
                        camera))
        else:
            sflux = np.empty((args.nspec, npix))

    #- Check if input simspec is for a continuum flat lamp instead of science
    #- This does not convolve to per-fiber resolution
    if args.simspec:
        if simspec.flavor == 'flat':
            log.info("Simulating flat lamp exposure")
            for i, camera in enumerate(qsim.instrument.cameras):
                channel = camera.name  #- from simspec, b/r/z not b0/r1/z9
                assert camera.output_wavelength.unit == u.Angstrom
                num_pixels = len(waves[channel])

                phot = list()
                for j in range(10):
                    cn = camera.name + str(j)
                    if cn in simspec.cameras:
                        camwave = simspec.cameras[cn].wave
                        dw = np.gradient(camwave)
                        phot.append(simspec.cameras[cn].phot)

                if len(phot) == 0:
                    raise RuntimeError(
                        'Unable to find a {} camera in input simspec'.format(
                            camera))
                else:
                    phot = np.vstack(phot)

                meanspec = resample_flux(waves[channel], camwave,
                                         np.average(phot / dw, axis=0))

                fiberflat = random_state.normal(loc=1.0,
                                                scale=1.0 / np.sqrt(meanspec),
                                                size=(nspec, num_pixels))
                ivar = np.tile(meanspec, [nspec, 1])
                mask = np.zeros((simspec.nspec, num_pixels), dtype=np.uint32)

                for kk in range((args.nspec + args.nstart - 1) // 500 + 1):
                    camera = channel + str(kk)
                    outfile = desispec.io.findfile('fiberflat', NIGHT, EXPID,
                                                   camera)
                    start = max(500 * kk, args.nstart)
                    end = min(500 * (kk + 1), nmax)

                    if (args.spectrograph <= kk):
                        log.info(
                            "Writing files for channel:{}, spectrograph:{}, spectra:{} to {}"
                            .format(channel, kk, start, end))

                    ff = FiberFlat(waves[channel],
                                   fiberflat[start:end, :],
                                   ivar[start:end, :],
                                   mask[start:end, :],
                                   meanspec,
                                   header=dict(CAMERA=camera))
                    write_fiberflat(outfile, ff)
                    filePath = desispec.io.findfile("fiberflat", NIGHT, EXPID,
                                                    camera)
                    log.info("Wrote file {}".format(filePath))

            sys.exit(0)

    # Repeat the simulation for all spectra
    fluxunits = 1e-17 * u.erg / (u.s * u.cm**2 * u.Angstrom)
    for j in range(args.nspec):

        thisobjtype = objtype[j]
        sys.stdout.flush()
        if flavor == 'arc':
            qsim.source.update_in('Quickgen source {0}'.format, 'perfect',
                                  wavelengths * u.Angstrom,
                                  spectra * fluxunits)
        else:
            qsim.source.update_in('Quickgen source {0}'.format(j),
                                  thisobjtype.lower(),
                                  wavelengths * u.Angstrom,
                                  spectra[j, :] * fluxunits)
        qsim.source.update_out()

        qsim.simulate()
        qsim.generate_random_noise(random_state)

        for i, output in enumerate(qsim.camera_output):
            assert output['observed_flux'].unit == 1e17 * fluxunits
            # Extract the simulation results needed to create our uncalibrated
            # frame output file.
            num_pixels = len(output)
            nobj[j, i, :num_pixels] = output['num_source_electrons'][:, 0]
            nsky[j, i, :num_pixels] = output['num_sky_electrons'][:, 0]
            nivar[j, i, :num_pixels] = 1.0 / output['variance_electrons'][:, 0]

            # Get results for our flux-calibrated output file.
            cframe_observedflux[
                j, i, :num_pixels] = 1e17 * output['observed_flux'][:, 0]
            cframe_ivar[
                j,
                i, :num_pixels] = 1e-34 * output['flux_inverse_variance'][:, 0]

            # Fill brick arrays from the results.
            camera = output.meta['name']
            trueflux[camera][j][:] = 1e17 * output['observed_flux'][:, 0]
            noisyflux[camera][j][:] = 1e17 * (
                output['observed_flux'][:, 0] +
                output['flux_calibration'][:, 0] *
                output['random_noise_electrons'][:, 0])
            obsivar[camera][j][:] = 1e-34 * output['flux_inverse_variance'][:,
                                                                            0]

            # Use the same noise realization in the cframe and frame, without any
            # additional noise from sky subtraction for now.
            frame_rand_noise[
                j, i, :num_pixels] = output['random_noise_electrons'][:, 0]
            cframe_rand_noise[j, i, :num_pixels] = 1e17 * (
                output['flux_calibration'][:, 0] *
                output['random_noise_electrons'][:, 0])

            # The sky output file represents a model fit to ~40 sky fibers.
            # We reduce the variance by a factor of 25 to account for this and
            # give the sky an independent (Gaussian) noise realization.
            sky_ivar[
                j,
                i, :num_pixels] = 25.0 / (output['variance_electrons'][:, 0] -
                                          output['num_source_electrons'][:, 0])
            sky_rand_noise[j, i, :num_pixels] = random_state.normal(
                scale=1.0 / np.sqrt(sky_ivar[j, i, :num_pixels]),
                size=num_pixels)

    armName = {"b": 0, "r": 1, "z": 2}
    for channel in 'brz':

        #Before writing, convert from counts/bin to counts/A (as in Pixsim output)
        #Quicksim Default:
        #FLUX - input spectrum resampled to this binning; no noise added [1e-17 erg/s/cm2/s/Ang]
        #COUNTS_OBJ - object counts in 0.5 Ang bin
        #COUNTS_SKY - sky counts in 0.5 Ang bin

        num_pixels = len(waves[channel])
        dwave = np.gradient(waves[channel])
        nobj[:, armName[channel], :num_pixels] /= dwave
        frame_rand_noise[:, armName[channel], :num_pixels] /= dwave
        nivar[:, armName[channel], :num_pixels] *= dwave**2
        nsky[:, armName[channel], :num_pixels] /= dwave
        sky_rand_noise[:, armName[channel], :num_pixels] /= dwave
        sky_ivar[:, armName[channel], :num_pixels] /= dwave**2

        # Now write the outputs in DESI standard file system. None of the output file can have more than 500 spectra

        # Looping over spectrograph
        for ii in range((args.nspec + args.nstart - 1) // 500 + 1):

            start = max(500 * ii,
                        args.nstart)  # first spectrum for a given spectrograph
            end = min(500 * (ii + 1),
                      nmax)  # last spectrum for the spectrograph

            if (args.spectrograph <= ii):
                camera = "{}{}".format(channel, ii)
                log.info(
                    "Writing files for channel:{}, spectrograph:{}, spectra:{} to {}"
                    .format(channel, ii, start, end))
                num_pixels = len(waves[channel])

                # Write frame file
                framefileName = desispec.io.findfile("frame", NIGHT, EXPID,
                                                     camera)

                frame_flux=nobj[start:end,armName[channel],:num_pixels]+ \
                nsky[start:end,armName[channel],:num_pixels] + \
                frame_rand_noise[start:end,armName[channel],:num_pixels]
                frame_ivar = nivar[start:end, armName[channel], :num_pixels]

                sh1 = frame_flux.shape[
                    0]  # required for slicing the resolution metric, resolusion matrix has (nspec,ndiag,wave)
                # for example if nstart =400, nspec=150: two spectrographs:
                # 400-499=> 0 spectrograph, 500-549 => 1
                if (args.nstart == start):
                    resol = resolution[channel][:sh1, :, :]
                else:
                    resol = resolution[channel][-sh1:, :, :]

                # must create desispec.Frame object
                frame=Frame(waves[channel], frame_flux, frame_ivar,\
                    resolution_data=resol, spectrograph=ii, \
                    fibermap=fibermap[start:end], \
                    meta=dict(CAMERA=camera, FLAVOR=simspec.flavor) )
                desispec.io.write_frame(framefileName, frame)

                framefilePath = desispec.io.findfile("frame", NIGHT, EXPID,
                                                     camera)
                log.info("Wrote file {}".format(framefilePath))

                if args.frameonly or simspec.flavor == 'arc':
                    continue

                # Write cframe file
                cframeFileName = desispec.io.findfile("cframe", NIGHT, EXPID,
                                                      camera)
                cframeFlux = cframe_observedflux[
                    start:end,
                    armName[channel], :num_pixels] + cframe_rand_noise[
                        start:end, armName[channel], :num_pixels]
                cframeIvar = cframe_ivar[start:end,
                                         armName[channel], :num_pixels]

                # must create desispec.Frame object
                cframe = Frame(waves[channel], cframeFlux, cframeIvar, \
                    resolution_data=resol, spectrograph=ii,
                    fibermap=fibermap[start:end],
                    meta=dict(CAMERA=camera, FLAVOR=simspec.flavor) )
                desispec.io.frame.write_frame(cframeFileName, cframe)

                cframefilePath = desispec.io.findfile("cframe", NIGHT, EXPID,
                                                      camera)
                log.info("Wrote file {}".format(cframefilePath))

                # Write sky file
                skyfileName = desispec.io.findfile("sky", NIGHT, EXPID, camera)
                skyflux=nsky[start:end,armName[channel],:num_pixels] + \
                sky_rand_noise[start:end,armName[channel],:num_pixels]
                skyivar = sky_ivar[start:end, armName[channel], :num_pixels]
                skymask = np.zeros(skyflux.shape, dtype=np.uint32)

                # must create desispec.Sky object
                skymodel = SkyModel(waves[channel],
                                    skyflux,
                                    skyivar,
                                    skymask,
                                    header=dict(CAMERA=camera))
                desispec.io.sky.write_sky(skyfileName, skymodel)

                skyfilePath = desispec.io.findfile("sky", NIGHT, EXPID, camera)
                log.info("Wrote file {}".format(skyfilePath))

                # Write calib file
                calibVectorFile = desispec.io.findfile("calib", NIGHT, EXPID,
                                                       camera)
                flux = cframe_observedflux[start:end,
                                           armName[channel], :num_pixels]
                phot = nobj[start:end, armName[channel], :num_pixels]
                calibration = np.zeros_like(phot)
                jj = (flux > 0)
                calibration[jj] = phot[jj] / flux[jj]

                #- TODO: what should calibivar be?
                #- For now, model it as the noise of combining ~10 spectra
                calibivar = 10 / cframe_ivar[start:end,
                                             armName[channel], :num_pixels]
                #mask=(1/calibivar>0).astype(int)??
                mask = np.zeros(calibration.shape, dtype=np.uint32)

                # write flux calibration
                fluxcalib = FluxCalib(waves[channel], calibration, calibivar,
                                      mask)
                write_flux_calibration(calibVectorFile, fluxcalib)

                calibfilePath = desispec.io.findfile("calib", NIGHT, EXPID,
                                                     camera)
                log.info("Wrote file {}".format(calibfilePath))
示例#2
0
def simulate(airmass=None,
             exptime=None,
             seeing=None,
             moon_frac=None,
             moon_sep=None,
             moon_alt=None,
             seed=1234,
             nspec=5000,
             brickname='testbrick',
             galsim=False,
             ra=None,
             dec=None):

    #- construct the simulator
    qsim = simulator.Simulator('desi')

    # Initialize random number generator to use.
    random_state = np.random.RandomState(seed)

    #- Create a blank fake fibermap for bricks
    fibermap = empty_fibermap(nspec)
    targetids = random_state.randint(2**62, size=nspec)
    fibermap['TARGETID'] = targetids
    night = get_night()
    expid = 0

    #- working out only ELG
    objtype = 'ELG'
    true_objtype = np.tile(np.array([objtype]), (nspec))

    #- Initialize the output truth table.
    spectra = []
    wavemin = desimodel.io.load_throughput('b').wavemin
    wavemax = desimodel.io.load_throughput('z').wavemax
    dw = 0.2
    wavelengths = np.arange(round(wavemin, 1), wavemax, dw)

    npix = len(wavelengths)
    truth = dict()
    meta = Table()
    truth['OBJTYPE'] = 'ELG' * nspec
    truth['FLUX'] = np.zeros((nspec, npix))
    truth['WAVE'] = wavelengths

    #- get the templates
    flux, tmpwave, meta1 = get_templates(wavelengths, seed=seed, nmodel=nspec)
    truth['FLUX'] = flux
    meta = vstack([meta, meta1])

    #- Add TARGETID and the true OBJTYPE to the metadata table.
    meta.add_column(Column(true_objtype, dtype=(str, 10), name='TRUE_OBJTYPE'))
    meta.add_column(Column(targetids, name='TARGETID'))

    #- Rename REDSHIFT -> TRUEZ anticipating later table joins with zbest.Z
    meta.rename_column('REDSHIFT', 'TRUEZ')

    waves, trueflux, noisyflux, obsivar, resolution, sflux = {}, {}, {}, {}, {}, {}

    #- Now simulate
    maxbin = 0
    nmax = nspec
    for camera in qsim.instrument.cameras:
        # Lookup this camera's resolution matrix and convert to the sparse
        # format used in desispec.
        R = Resolution(camera.get_output_resolution_matrix())
        resolution[camera.name] = np.tile(R.to_fits_array(), [nspec, 1, 1])
        waves[camera.name] = (camera.output_wavelength.to(
            u.Angstrom).value.astype(np.float32))
        nwave = len(waves[camera.name])
        maxbin = max(maxbin, len(waves[camera.name]))
        nobj = np.zeros((nmax, 3, maxbin))  # object photons
        nsky = np.zeros((nmax, 3, maxbin))  # sky photons
        nivar = np.zeros((nmax, 3, maxbin))  # inverse variance (object+sky)
        cframe_observedflux = np.zeros(
            (nmax, 3, maxbin))  # calibrated object flux
        cframe_ivar = np.zeros(
            (nmax, 3, maxbin))  # inverse variance of calibrated object flux
        cframe_rand_noise = np.zeros(
            (nmax, 3, maxbin))  # random Gaussian noise to calibrated flux
        sky_ivar = np.zeros((nmax, 3, maxbin))  # inverse variance of sky
        sky_rand_noise = np.zeros(
            (nmax, 3, maxbin))  # random Gaussian noise to sky only
        frame_rand_noise = np.zeros(
            (nmax, 3, maxbin))  # random Gaussian noise to nobj+nsky
        trueflux[camera.name] = np.empty(
            (nspec, nwave))  # calibrated brick flux
        noisyflux[camera.name] = np.empty(
            (nspec, nwave))  # brick flux with noise
        obsivar[camera.name] = np.empty(
            (nspec, nwave))  # inverse variance of brick flux

        sflux = np.empty((nspec, npix))

    #- Repeat the simulation for all spectra
    fluxunits = 1e-17 * u.erg / (u.s * u.cm**2 * u.Angstrom)
    spectra = truth['FLUX'] * 1.0e17
    print("Simulating Spectra")
    for j in range(nspec):
        print("Simulating %s/%s spectra" % (j, nspec), end='\r')
        thisobjtype = 'ELG'
        sys.stdout.flush()

        #- update qsim using conditions
        if airmass is None:
            thisairmass = None
        else:
            thisairmass = airmass[j]

        if seeing is None:
            thisseeing = None
        else:
            thisseeing = seeing[j]

        if moon_frac is None:
            thismoon_frac = None
        else:
            thismoon_frac = moon_frac[j]

        if moon_sep is None:
            thismoon_sep = None
        else:
            thismoon_sep = moon_sep[j]

        if moon_alt is None:
            thismoon_alt = None
        else:
            thismoon_alt = moon_alt[j]

        if exptime is None:
            thisexptime = None

        else:
            thisexptime = exptime[j]

        nqsim = update_simulator(qsim,
                                 airmass=thisairmass,
                                 exptime=thisexptime,
                                 seeing=thisseeing,
                                 moon_frac=thismoon_frac,
                                 moon_sep=thismoon_sep,
                                 moon_alt=thismoon_alt,
                                 galsim=galsim)

        nqsim.source.update_in('Quickgen source {0}'.format(j),
                               thisobjtype.lower(), wavelengths * u.Angstrom,
                               spectra[j, :] * fluxunits)
        nqsim.source.update_out()

        nqsim.simulate()
        nqsim.generate_random_noise(random_state)

        sflux[j][:] = 1e17 * qsim.source.flux_in.to(fluxunits).value

        for i, output in enumerate(nqsim.camera_output):
            assert output['observed_flux'].unit == 1e17 * fluxunits
            # Extract the simulation results needed to create our uncalibrated
            # frame output file.
            num_pixels = len(output)
            nobj[j, i, :num_pixels] = output['num_source_electrons'][:, 0]
            nsky[j, i, :num_pixels] = output['num_sky_electrons'][:, 0]
            nivar[j, i, :num_pixels] = 1.0 / output['variance_electrons'][:, 0]

            # Get results for our flux-calibrated output file.
            cframe_observedflux[
                j, i, :num_pixels] = 1e17 * output['observed_flux'][:, 0]
            cframe_ivar[
                j,
                i, :num_pixels] = 1e-34 * output['flux_inverse_variance'][:, 0]

            # Fill brick arrays from the results.
            camera = output.meta['name']
            trueflux[camera][j][:] = 1e17 * output['observed_flux'][:, 0]
            noisyflux[camera][j][:] = 1e17 * (
                output['observed_flux'][:, 0] +
                output['flux_calibration'][:, 0] *
                output['random_noise_electrons'][:, 0])
            #return output
            obsivar[camera][j][:] = 1e-34 * output['flux_inverse_variance'][:,
                                                                            0]

            # Use the same noise realization in the cframe and frame, without any
            # additional noise from sky subtraction for now.
            frame_rand_noise[
                j, i, :num_pixels] = output['random_noise_electrons'][:, 0]
            cframe_rand_noise[j, i, :num_pixels] = 1e17 * (
                output['flux_calibration'][:, 0] *
                output['random_noise_electrons'][:, 0])

            # The sky output file represents a model fit to ~40 sky fibers.
            # We reduce the variance by a factor of 25 to account for this and
            # give the sky an independent (Gaussian) noise realization.
            sky_ivar[
                j,
                i, :num_pixels] = 25.0 / (output['variance_electrons'][:, 0] -
                                          output['num_source_electrons'][:, 0])
            sky_rand_noise[j, i, :num_pixels] = random_state.normal(
                scale=1.0 / np.sqrt(sky_ivar[j, i, :num_pixels]),
                size=num_pixels)
            cframe_flux = cframe_observedflux[
                j, i, :num_pixels] + cframe_rand_noise[j, i, :num_pixels]

    armName = {"b": 0, "r": 1, "z": 2}
    for channel in 'brz':

        num_pixels = len(waves[channel])
        dwave = np.gradient(waves[channel])
        nobj[:, armName[channel], :num_pixels] /= dwave
        frame_rand_noise[:, armName[channel], :num_pixels] /= dwave
        nivar[:, armName[channel], :num_pixels] *= dwave**2
        nsky[:, armName[channel], :num_pixels] /= dwave
        sky_rand_noise[:, armName[channel], :num_pixels] /= dwave
        sky_ivar[:, armName[channel], :num_pixels] /= dwave**2

        # Now write the outputs in DESI standard file system. None of the output file can have more than 500 spectra

        # Output brick files
        if ra is None or dec is None:
            filename = 'brick-{}-{}.fits'.format(channel, brickname)
            filepath = os.path.normpath(
                os.path.join('{}'.format(brickname), filename))
            if os.path.exists(filepath):
                os.remove(filepath)
            print('Writing {}'.format(filepath))

            header = dict(BRICKNAM=brickname, CHANNEL=channel)
            brick = Brick(filepath, mode='update', header=header)
            brick.add_objects(noisyflux[channel], obsivar[channel],
                              waves[channel], resolution[channel], fibermap,
                              night, expid)
            brick.close()
            """
            # Append truth to the file. Note: we add the resolution-convolved true
            # flux, not the high resolution source flux, which makes chi2
            # calculations easier.
            header = fitsheader(header)
            fx = fits.open(filepath, mode='append')
            _add_truth(fx, header, meta, trueflux, sflux, wavelengths, channel)
            fx.flush()
            fx.close()
            #sys.stdout.close()
            """
            print("Wrote file {}".format(filepath))
        else:
            bricknames = get_bricknames(ra, dec)
            fibermap['BRICKNAME'] = bricknames
            bricknames = set(bricknames)
            print("No. of bricks: {}".format(len(bricknames)))
            print("Writing brick files")
            for brick_name in bricknames:

                thisbrick = (fibermap['BRICKNAME'] == brick_name)
                brickdata = fibermap[thisbrick]

                fibers = brickdata['FIBER']  #np.mod(brickdata['FIBER'],nspec)
                filename = 'brick-{}-{}.fits'.format(channel, brick_name)
                filepath = os.path.normpath(
                    os.path.join('./{}'.format(brick_name), filename))
                if os.path.exists(filepath):
                    os.remove(filepath)
                #print('Writing {}'.format(filepath))

                header = dict(BRICKNAM=brick_name, CHANNEL=channel)
                brick = Brick(filepath, mode='update', header=header)
                brick.add_objects(noisyflux[channel][fibers],
                                  obsivar[channel][fibers], waves[channel],
                                  resolution[channel][fibers], brickdata,
                                  night, expid)
                brick.close()
            print("Finished writing brick files for {} bricks".format(
                len(bricknames)))
    #- make a truth file
    header = fitsheader(header)
    make_truthfile(header, meta, trueflux, sflux, wavelengths)
示例#3
0
def batch_pixsim(batchfile,
                 flavors,
                 nspec=5000,
                 night=None,
                 expids=None,
                 nodes=None,
                 pixprod=None,
                 desi_spectro_sim=None,
                 seed=None):
    '''
    Write a slurm batch script for run newexp-desi for the list of flavors
    '''
    nexp = len(flavors)
    nspectrographs = (nspec - 1) // 500 + 1
    ntasks = nexp * 3
    timestr = '00:30:00'
    logfile = '{}.%j.log'.format(batchfile)

    np.random.seed(seed)
    seeds = np.random.randint(2**32, size=nexp)

    if night is None:
        night = obs.get_night()

    if expids is None:
        expids = obs.get_next_expid(nexp)

    assert len(expids) == len(flavors)

    if pixprod is None:
        if 'PIXPROD' in os.environ:
            pixprod = os.environ['PIXPROD']
        else:
            raise ValueError('must provide pixprod or set $PIXPROD')

    if desi_spectro_sim is None:
        if 'DESI_SPECTRO_SIM' in os.environ:
            desi_spectro_sim = os.environ['DESI_SPECTRO_SIM']
        else:
            raise ValueError(
                'must provide desi_spectro_sim or set $DESI_SPECTRO_SIM')

    outdir = os.path.normpath(os.path.join(desi_spectro_sim, pixprod, night))
    log.info('output dir {}'.format(outdir))

    if nodes is None:
        # nodes = calc_nodes(ntasks, tasktime=5, maxtime=20)
        nodes = nexp * nspectrographs

    cmd = "srun -n {nspectrographs} -N {nspectrographs} -c $nproc /usr/bin/time pixsim-desi --mpi --verbose --cosmics --night {night} --expid {expid} --seed {seed}"
    with open(batchfile, 'w') as fx:
        fx.write("#!/bin/bash -l\n\n")
        fx.write("#SBATCH --partition=debug\n")
        fx.write("#SBATCH --account=desi\n")
        fx.write("#SBATCH --nodes={}\n".format(nodes))
        fx.write("#SBATCH --time={}\n".format(timestr))
        fx.write("#SBATCH --job-name=pixsim\n")
        fx.write("#SBATCH --output={}\n".format(logfile))

        fx.write("if [ ${NERSC_HOST} = edison ]; then\n")
        fx.write("  nproc=24\n")
        fx.write("else\n")
        fx.write("  nproc=32\n")
        fx.write("fi\n\n")

        fx.write('export DESI_SPECTRO_SIM={}\n'.format(desi_spectro_sim))
        fx.write('export PIXPROD={}\n'.format(pixprod))

        fx.write('\necho Starting at `date`\n')

        for expid, flavor, seed in zip(expids, flavors, seeds):
            fx.write('\n#- Exposure {} ({})\n'.format(expid, flavor))

            cx = cmd.format(night=night,
                            expid=expid,
                            nspectrographs=nspectrographs,
                            seed=seed)
            fx.write(cx + ' &\n')

        fx.write('\nwait\n')

        fx.write('\n#- Preprocess raw data\n')
        cmd = 'srun -n 1 -N 1 desi_preproc --infile {infile} --outdir {outdir} --cameras {cameras}'
        outdir = os.path.join(desi_spectro_sim, pixprod, night)
        for expid in expids:
            infile = desispec.io.findfile('raw',
                                          night=night,
                                          expid=expid,
                                          outdir=outdir)
            for i in range(nspectrographs):
                cameras = 'b{},r{},z{}'.format(i, i, i)
                cx = cmd.format(infile=infile, outdir=outdir, cameras=cameras)
                fx.write(cx + ' &\n')

        fx.write('\nwait\n')
        fx.write('echo Done at `date`\n')
示例#4
0
def batch_newexp(batchfile,
                 flavors,
                 nspec=5000,
                 night=None,
                 expids=None,
                 nodes=None,
                 pixprod=None,
                 desi_spectro_sim=None,
                 tileids=None,
                 seed=None):
    '''
    Write a slurm batch script for run newexp-desi for the list of flavors
    '''
    nexp = len(flavors)
    timestr = '00:30:00'
    logfile = '{}.%j.log'.format(batchfile)

    np.random.seed(seed)
    seeds = np.random.randint(2**32, size=nexp)

    if night is None:
        night = obs.get_night()

    if expids is None:
        expids = obs.get_next_expid(nexp)

    if nodes is None:
        nodes = calc_nodes(nexp, tasktime=1.5, maxtime=20)

    if tileids is None:
        tileids = list()
        for flavor in flavors:
            flavor = flavor.lower()
            t = obs.get_next_tileid(program=flavor)
            tileids.append(t)
            if flavor in ('arc', 'flat'):
                obs.update_obslog(obstype=flavor, program='calib', tileid=t)
            elif flavor in ('bright', 'bgs', 'mws'):
                obs.update_obslog(obstype='science',
                                  program='bright',
                                  tileid=t)
            elif flavor in ('gray', 'grey'):
                obs.update_obslog(obstype='science', program='gray', tileid=t)
            else:
                obs.update_obslog(obstype='science', program='dark', tileid=t)

    if pixprod is None:
        if 'PIXPROD' in os.environ:
            pixprod = os.environ['PIXPROD']
        else:
            raise ValueError('must provide pixprod or set $PIXPROD')

    if desi_spectro_sim is None:
        if 'DESI_SPECTRO_SIM' in os.environ:
            desi_spectro_sim = os.environ['DESI_SPECTRO_SIM']
        else:
            raise ValueError(
                'must provide desi_spectro_sim or set $DESI_SPECTRO_SIM')

    log.info('output dir {}/{}/{}'.format(desi_spectro_sim, pixprod, night))

    assert len(expids) == len(flavors)

    cmd = "srun -n 1 -N 1 -c $nproc /usr/bin/time newexp-desi --night {night} --nspec {nspec} --flavor {flavor} --expid {expid} --tileid {tileid} --seed {seed}"
    with open(batchfile, 'w') as fx:
        fx.write("#!/bin/bash -l\n\n")
        fx.write("#SBATCH --partition=debug\n")
        fx.write("#SBATCH --account=desi\n")
        fx.write("#SBATCH --nodes={}\n".format(nodes))
        fx.write("#SBATCH --time={}\n".format(timestr))
        fx.write("#SBATCH --job-name=newexp\n")
        fx.write("#SBATCH --output={}\n".format(logfile))

        fx.write("if [ ${NERSC_HOST} = edison ]; then\n")
        fx.write("  nproc=24\n")
        fx.write("else\n")
        fx.write("  nproc=32\n")
        fx.write("fi\n\n")

        fx.write('export DESI_SPECTRO_SIM={}\n'.format(desi_spectro_sim))
        fx.write('export PIXPROD={}\n'.format(pixprod))
        fx.write('\n')
        fx.write('echo Starting at `date`\n\n')

        fx.write('mkdir -p $DESI_SPECTRO_SIM/$PIXPROD/etc\n')
        fx.write('mkdir -p $DESI_SPECTRO_SIM/$PIXPROD/{}\n'.format(night))
        fx.write('\n')

        for expid, flavor, tileid, seed in zip(expids, flavors, tileids,
                                               seeds):
            fx.write(
                cmd.format(nspec=nspec,
                           night=night,
                           expid=expid,
                           flavor=flavor,
                           tileid=tileid,
                           seed=seed) + ' &\n')

        fx.write('\nwait\n')
        fx.write('\necho Done at `date`\n')

    return expids
示例#5
0
def main(args):

    # Set up the logger
    if args.verbose:
        log = get_logger(DEBUG)
    else:
        log = get_logger()

    # Make sure all necessary environment variables are set
    DESI_SPECTRO_REDUX_DIR="./quickGen"

    if 'DESI_SPECTRO_REDUX' not in os.environ:

        log.info('DESI_SPECTRO_REDUX environment is not set.')

    else:
        DESI_SPECTRO_REDUX_DIR=os.environ['DESI_SPECTRO_REDUX']

    if os.path.exists(DESI_SPECTRO_REDUX_DIR):

        if not os.path.isdir(DESI_SPECTRO_REDUX_DIR):
            raise RuntimeError("Path %s Not a directory"%DESI_SPECTRO_REDUX_DIR)
    else:
        try:
            os.makedirs(DESI_SPECTRO_REDUX_DIR)
        except:
            raise

    SPECPROD_DIR='specprod'
    if 'SPECPROD' not in os.environ:
        log.info('SPECPROD environment is not set.')
    else:
        SPECPROD_DIR=os.environ['SPECPROD']
    prod_Dir=specprod_root()

    if os.path.exists(prod_Dir):

        if not os.path.isdir(prod_Dir):
            raise RuntimeError("Path %s Not a directory"%prod_Dir)
    else:
        try:
            os.makedirs(prod_Dir)
        except:
            raise

    # Initialize random number generator to use.
    np.random.seed(args.seed)
    random_state = np.random.RandomState(args.seed)

    # Derive spectrograph number from nstart if needed
    if args.spectrograph is None:
        args.spectrograph = args.nstart / 500

    # Read fibermapfile to get object type, night and expid
    if args.fibermap:
        log.info("Reading fibermap file {}".format(args.fibermap))
        fibermap=read_fibermap(args.fibermap)
        objtype = get_source_types(fibermap)
        stdindx=np.where(objtype=='STD') # match STD with STAR
        mwsindx=np.where(objtype=='MWS_STAR') # match MWS_STAR with STAR
        bgsindx=np.where(objtype=='BGS') # match BGS with LRG
        objtype[stdindx]='STAR'
        objtype[mwsindx]='STAR'
        objtype[bgsindx]='LRG'
        NIGHT=fibermap.meta['NIGHT']
        EXPID=fibermap.meta['EXPID']
    else:
        # Create a blank fake fibermap
        fibermap = empty_fibermap(args.nspec)
        targetids = random_state.randint(2**62, size=args.nspec)
        fibermap['TARGETID'] = targetids
        night = get_night()
        expid = 0

    log.info("Initializing SpecSim with config {}".format(args.config))
    desiparams = load_desiparams()
    qsim = get_simulator(args.config, num_fibers=1)

    if args.simspec:
        # Read the input file
        log.info('Reading input file {}'.format(args.simspec))
        simspec = desisim.io.read_simspec(args.simspec)
        nspec = simspec.nspec
        if simspec.flavor == 'arc':
            log.warning("quickgen doesn't generate flavor=arc outputs")
            return
        else:
            wavelengths = simspec.wave
            spectra = simspec.flux
        if nspec < args.nspec:
            log.info("Only {} spectra in input file".format(nspec))
            args.nspec = nspec

    else:
        # Initialize the output truth table.
        spectra = []
        wavelengths = qsim.source.wavelength_out.to(u.Angstrom).value
        npix = len(wavelengths)
        truth = dict()
        meta = Table()
        truth['OBJTYPE'] = np.zeros(args.nspec, dtype=(str, 10))
        truth['FLUX'] = np.zeros((args.nspec, npix))
        truth['WAVE'] = wavelengths
        jj = list()

        for thisobj in set(true_objtype):
            ii = np.where(true_objtype == thisobj)[0]
            nobj = len(ii)
            truth['OBJTYPE'][ii] = thisobj
            log.info('Generating {} template'.format(thisobj))

            # Generate the templates
            if thisobj == 'ELG':
                elg = desisim.templates.ELG(wave=wavelengths, add_SNeIa=args.add_SNeIa)
                flux, tmpwave, meta1 = elg.make_templates(nmodel=nobj, seed=args.seed, zrange=args.zrange_elg,sne_rfluxratiorange=args.sne_rfluxratiorange)
            elif thisobj == 'LRG':
                lrg = desisim.templates.LRG(wave=wavelengths, add_SNeIa=args.add_SNeIa)
                flux, tmpwave, meta1 = lrg.make_templates(nmodel=nobj, seed=args.seed, zrange=args.zrange_lrg,sne_rfluxratiorange=args.sne_rfluxratiorange)
            elif thisobj == 'QSO':
                qso = desisim.templates.QSO(wave=wavelengths)
                flux, tmpwave, meta1 = qso.make_templates(nmodel=nobj, seed=args.seed, zrange=args.zrange_qso)
            elif thisobj == 'BGS':
                bgs = desisim.templates.BGS(wave=wavelengths, add_SNeIa=args.add_SNeIa)
                flux, tmpwave, meta1 = bgs.make_templates(nmodel=nobj, seed=args.seed, zrange=args.zrange_bgs,rmagrange=args.rmagrange_bgs,sne_rfluxratiorange=args.sne_rfluxratiorange)
            elif thisobj =='STD':
                std = desisim.templates.STD(wave=wavelengths)
                flux, tmpwave, meta1 = std.make_templates(nmodel=nobj, seed=args.seed)
            elif thisobj == 'QSO_BAD': # use STAR template no color cuts
                star = desisim.templates.STAR(wave=wavelengths)
                flux, tmpwave, meta1 = star.make_templates(nmodel=nobj, seed=args.seed)
            elif thisobj == 'MWS_STAR' or thisobj == 'MWS':
                mwsstar = desisim.templates.MWS_STAR(wave=wavelengths)
                flux, tmpwave, meta1 = mwsstar.make_templates(nmodel=nobj, seed=args.seed)
            elif thisobj == 'WD':
                wd = desisim.templates.WD(wave=wavelengths)
                flux, tmpwave, meta1 = wd.make_templates(nmodel=nobj, seed=args.seed)
            elif thisobj == 'SKY':
                flux = np.zeros((nobj, npix))
                meta1 = Table(dict(REDSHIFT=np.zeros(nobj, dtype=np.float32)))
            elif thisobj == 'TEST':
                flux = np.zeros((args.nspec, npix))
                indx = np.where(wave>5800.0-1E-6)[0][0]
                ref_integrated_flux = 1E-10
                ref_cst_flux_density = 1E-17
                single_line = (np.arange(args.nspec)%2 == 0).astype(np.float32)
                continuum   = (np.arange(args.nspec)%2 == 1).astype(np.float32)

                for spec in range(args.nspec) :
                    flux[spec,indx] = single_line[spec]*ref_integrated_flux/np.gradient(wavelengths)[indx] # single line
                    flux[spec] += continuum[spec]*ref_cst_flux_density # flat continuum

                meta1 = Table(dict(REDSHIFT=np.zeros(args.nspec, dtype=np.float32),
                                   LINE=wave[indx]*np.ones(args.nspec, dtype=np.float32),
                                   LINEFLUX=single_line*ref_integrated_flux,
                                   CONSTFLUXDENSITY=continuum*ref_cst_flux_density))
            else:
                log.fatal('Unknown object type {}'.format(thisobj))
                sys.exit(1)

            # Pack it in.
            truth['FLUX'][ii] = flux
            meta = vstack([meta, meta1])
            jj.append(ii.tolist())

            # Sanity check on units; templates currently return ergs, not 1e-17 ergs...
            # assert (thisobj == 'SKY') or (np.max(truth['FLUX']) < 1e-6)

        # Sort the metadata table.
        jj = sum(jj,[])
        meta_new = Table()
        for k in range(args.nspec):
            index = int(np.where(np.array(jj) == k)[0])
            meta_new = vstack([meta_new, meta[index]])
        meta = meta_new

        # Add TARGETID and the true OBJTYPE to the metadata table.
        meta.add_column(Column(true_objtype, dtype=(str, 10), name='TRUE_OBJTYPE'))
        meta.add_column(Column(targetids, name='TARGETID'))

        # Rename REDSHIFT -> TRUEZ anticipating later table joins with zbest.Z
        meta.rename_column('REDSHIFT', 'TRUEZ')

    # explicitly set location on focal plane if needed to support airmass
    # variations when using specsim v0.5
    if qsim.source.focal_xy is None:
        qsim.source.focal_xy = (u.Quantity(0, 'mm'), u.Quantity(100, 'mm'))

    # Set simulation parameters from the simspec header or desiparams
    bright_objects = ['bgs','mws','bright','BGS','MWS','BRIGHT_MIX']
    gray_objects = ['gray','grey']
    if args.simspec is None:
        object_type = objtype
        flavor = None
    elif simspec.flavor == 'science':
        object_type = None
        flavor = simspec.header['PROGRAM']
    else:
        object_type = None
        flavor = simspec.flavor
        log.warning('Maybe using an outdated simspec file with flavor={}'.format(flavor))

    # Set airmass
    if args.airmass is not None:
        qsim.atmosphere.airmass = args.airmass
    elif args.simspec and 'AIRMASS' in simspec.header:
        qsim.atmosphere.airmass = simspec.header['AIRMASS']
    else:
        qsim.atmosphere.airmass =  1.25   # Science Req. Doc L3.3.2
        
    # Set exptime
    if args.exptime is not None:
        qsim.observation.exposure_time = args.exptime * u.s
    elif args.simspec and 'EXPTIME' in simspec.header:
        qsim.observation.exposure_time = simspec.header['EXPTIME'] * u.s
    elif objtype in bright_objects:
        qsim.observation.exposure_time = desiparams['exptime_bright'] * u.s
    else:
        qsim.observation.exposure_time = desiparams['exptime_dark'] * u.s

    # Set Moon Phase
    if args.moon_phase is not None:
        qsim.atmosphere.moon.moon_phase = args.moon_phase
    elif args.simspec and 'MOONFRAC' in simspec.header:
        qsim.atmosphere.moon.moon_phase = simspec.header['MOONFRAC']
    elif flavor in bright_objects or object_type in bright_objects:
        qsim.atmosphere.moon.moon_phase = 0.7
    elif flavor in gray_objects:
        qsim.atmosphere.moon.moon_phase = 0.1
    else:
        qsim.atmosphere.moon.moon_phase = 0.5
        
    # Set Moon Zenith
    if args.moon_zenith is not None:
        qsim.atmosphere.moon.moon_zenith = args.moon_zenith * u.deg
    elif args.simspec and 'MOONALT' in simspec.header:
        qsim.atmosphere.moon.moon_zenith = simspec.header['MOONALT'] * u.deg
    elif flavor in bright_objects or object_type in bright_objects:
        qsim.atmosphere.moon.moon_zenith = 30 * u.deg
    elif flavor in gray_objects:
        qsim.atmosphere.moon.moon_zenith = 80 * u.deg
    else:
        qsim.atmosphere.moon.moon_zenith = 100 * u.deg

    # Set Moon - Object Angle
    if args.moon_angle is not None:
        qsim.atmosphere.moon.separation_angle = args.moon_angle * u.deg
    elif args.simspec and 'MOONSEP' in simspec.header:
        qsim.atmosphere.moon.separation_angle = simspec.header['MOONSEP'] * u.deg
    elif flavor in bright_objects or object_type in bright_objects:
        qsim.atmosphere.moon.separation_angle = 50 * u.deg
    elif flavor in gray_objects:
        qsim.atmosphere.moon.separation_angle = 60 * u.deg
    else:
        qsim.atmosphere.moon.separation_angle = 60 * u.deg

    # Initialize per-camera output arrays that will be saved
    waves, trueflux, noisyflux, obsivar, resolution, sflux = {}, {}, {}, {}, {}, {}

    maxbin = 0
    nmax= args.nspec
    for camera in qsim.instrument.cameras:
        # Lookup this camera's resolution matrix and convert to the sparse
        # format used in desispec.
        R = Resolution(camera.get_output_resolution_matrix())
        resolution[camera.name] = np.tile(R.to_fits_array(), [args.nspec, 1, 1])
        waves[camera.name] = (camera.output_wavelength.to(u.Angstrom).value.astype(np.float32))
        nwave = len(waves[camera.name])
        maxbin = max(maxbin, len(waves[camera.name]))
        nobj = np.zeros((nmax,3,maxbin)) # object photons
        nsky = np.zeros((nmax,3,maxbin)) # sky photons
        nivar = np.zeros((nmax,3,maxbin)) # inverse variance (object+sky)
        cframe_observedflux = np.zeros((nmax,3,maxbin))  # calibrated object flux
        cframe_ivar = np.zeros((nmax,3,maxbin)) # inverse variance of calibrated object flux
        cframe_rand_noise = np.zeros((nmax,3,maxbin)) # random Gaussian noise to calibrated flux
        sky_ivar = np.zeros((nmax,3,maxbin)) # inverse variance of sky
        sky_rand_noise = np.zeros((nmax,3,maxbin)) # random Gaussian noise to sky only
        frame_rand_noise = np.zeros((nmax,3,maxbin)) # random Gaussian noise to nobj+nsky
        trueflux[camera.name] = np.empty((args.nspec, nwave)) # calibrated flux
        noisyflux[camera.name] = np.empty((args.nspec, nwave)) # observed flux with noise
        obsivar[camera.name] = np.empty((args.nspec, nwave)) # inverse variance of flux
        if args.simspec:
            for i in range(10):
                cn = camera.name + str(i)
                if cn in simspec.cameras:
                    dw = np.gradient(simspec.cameras[cn].wave)
                    break
            else:
                raise RuntimeError('Unable to find a {} camera in input simspec'.format(camera))
        else:
            sflux = np.empty((args.nspec, npix))

    #- Check if input simspec is for a continuum flat lamp instead of science
    #- This does not convolve to per-fiber resolution
    if args.simspec:
        if simspec.flavor == 'flat':
            log.info("Simulating flat lamp exposure")
            for i,camera in enumerate(qsim.instrument.cameras):
                channel = camera.name   #- from simspec, b/r/z not b0/r1/z9
                assert camera.output_wavelength.unit == u.Angstrom
                num_pixels = len(waves[channel])

                phot = list()
                for j in range(10):
                    cn = camera.name + str(j)
                    if cn in simspec.cameras:
                        camwave = simspec.cameras[cn].wave
                        dw = np.gradient(camwave)
                        phot.append(simspec.cameras[cn].phot)

                if len(phot) == 0:
                    raise RuntimeError('Unable to find a {} camera in input simspec'.format(camera))
                else:
                    phot = np.vstack(phot)

                meanspec = resample_flux(
                    waves[channel], camwave, np.average(phot/dw, axis=0))

                fiberflat = random_state.normal(loc=1.0,
                    scale=1.0 / np.sqrt(meanspec), size=(nspec, num_pixels))
                ivar = np.tile(meanspec, [nspec, 1])
                mask = np.zeros((simspec.nspec, num_pixels), dtype=np.uint32)

                for kk in range((args.nspec+args.nstart-1)//500+1):
                    camera = channel+str(kk)
                    outfile = desispec.io.findfile('fiberflat', NIGHT, EXPID, camera)
                    start=max(500*kk,args.nstart)
                    end=min(500*(kk+1),nmax)

                    if (args.spectrograph <= kk):
                        log.info("Writing files for channel:{}, spectrograph:{}, spectra:{} to {}".format(channel,kk,start,end))

                    ff = FiberFlat(
                        waves[channel], fiberflat[start:end,:],
                        ivar[start:end,:], mask[start:end,:], meanspec,
                        header=dict(CAMERA=camera))
                    write_fiberflat(outfile, ff)
                    filePath=desispec.io.findfile("fiberflat",NIGHT,EXPID,camera)
                    log.info("Wrote file {}".format(filePath))

            sys.exit(0)

    # Repeat the simulation for all spectra
    fluxunits = 1e-17 * u.erg / (u.s * u.cm ** 2 * u.Angstrom)
    for j in range(args.nspec):

        thisobjtype = objtype[j]
        sys.stdout.flush()
        if flavor == 'arc':
            qsim.source.update_in(
                'Quickgen source {0}'.format, 'perfect',
                wavelengths * u.Angstrom, spectra * fluxunits)
        else:
            qsim.source.update_in(
                'Quickgen source {0}'.format(j), thisobjtype.lower(),
                wavelengths * u.Angstrom, spectra[j, :] * fluxunits)
        qsim.source.update_out()

        qsim.simulate()
        qsim.generate_random_noise(random_state)

        for i, output in enumerate(qsim.camera_output):
            assert output['observed_flux'].unit == 1e17 * fluxunits
            # Extract the simulation results needed to create our uncalibrated
            # frame output file.
            num_pixels = len(output)
            nobj[j, i, :num_pixels] = output['num_source_electrons'][:,0]
            nsky[j, i, :num_pixels] = output['num_sky_electrons'][:,0]
            nivar[j, i, :num_pixels] = 1.0 / output['variance_electrons'][:,0]

            # Get results for our flux-calibrated output file.
            cframe_observedflux[j, i, :num_pixels] = 1e17 * output['observed_flux'][:,0]
            cframe_ivar[j, i, :num_pixels] = 1e-34 * output['flux_inverse_variance'][:,0]

            # Fill brick arrays from the results.
            camera = output.meta['name']
            trueflux[camera][j][:] = 1e17 * output['observed_flux'][:,0]
            noisyflux[camera][j][:] = 1e17 * (output['observed_flux'][:,0] +
                output['flux_calibration'][:,0] * output['random_noise_electrons'][:,0])
            obsivar[camera][j][:] = 1e-34 * output['flux_inverse_variance'][:,0]

            # Use the same noise realization in the cframe and frame, without any
            # additional noise from sky subtraction for now.
            frame_rand_noise[j, i, :num_pixels] = output['random_noise_electrons'][:,0]
            cframe_rand_noise[j, i, :num_pixels] = 1e17 * (
                output['flux_calibration'][:,0] * output['random_noise_electrons'][:,0])

            # The sky output file represents a model fit to ~40 sky fibers.
            # We reduce the variance by a factor of 25 to account for this and
            # give the sky an independent (Gaussian) noise realization.
            sky_ivar[j, i, :num_pixels] = 25.0 / (
                output['variance_electrons'][:,0] - output['num_source_electrons'][:,0])
            sky_rand_noise[j, i, :num_pixels] = random_state.normal(
                scale=1.0 / np.sqrt(sky_ivar[j,i,:num_pixels]),size=num_pixels)

    armName={"b":0,"r":1,"z":2}
    for channel in 'brz':

        #Before writing, convert from counts/bin to counts/A (as in Pixsim output)
        #Quicksim Default:
        #FLUX - input spectrum resampled to this binning; no noise added [1e-17 erg/s/cm2/s/Ang]
        #COUNTS_OBJ - object counts in 0.5 Ang bin
        #COUNTS_SKY - sky counts in 0.5 Ang bin

        num_pixels = len(waves[channel])
        dwave=np.gradient(waves[channel])
        nobj[:,armName[channel],:num_pixels]/=dwave
        frame_rand_noise[:,armName[channel],:num_pixels]/=dwave
        nivar[:,armName[channel],:num_pixels]*=dwave**2
        nsky[:,armName[channel],:num_pixels]/=dwave
        sky_rand_noise[:,armName[channel],:num_pixels]/=dwave
        sky_ivar[:,armName[channel],:num_pixels]/=dwave**2

        # Now write the outputs in DESI standard file system. None of the output file can have more than 500 spectra

        # Looping over spectrograph
        for ii in range((args.nspec+args.nstart-1)//500+1):

            start=max(500*ii,args.nstart) # first spectrum for a given spectrograph
            end=min(500*(ii+1),nmax) # last spectrum for the spectrograph

            if (args.spectrograph <= ii):
                camera = "{}{}".format(channel, ii)
                log.info("Writing files for channel:{}, spectrograph:{}, spectra:{} to {}".format(channel,ii,start,end))
                num_pixels = len(waves[channel])

                # Write frame file
                framefileName=desispec.io.findfile("frame",NIGHT,EXPID,camera)

                frame_flux=nobj[start:end,armName[channel],:num_pixels]+ \
                nsky[start:end,armName[channel],:num_pixels] + \
                frame_rand_noise[start:end,armName[channel],:num_pixels]
                frame_ivar=nivar[start:end,armName[channel],:num_pixels]

                sh1=frame_flux.shape[0]  # required for slicing the resolution metric, resolusion matrix has (nspec,ndiag,wave)
                                          # for example if nstart =400, nspec=150: two spectrographs:
                                          # 400-499=> 0 spectrograph, 500-549 => 1
                if (args.nstart==start):
                    resol=resolution[channel][:sh1,:,:]
                else:
                    resol=resolution[channel][-sh1:,:,:]

                # must create desispec.Frame object
                frame=Frame(waves[channel], frame_flux, frame_ivar,\
                    resolution_data=resol, spectrograph=ii, \
                    fibermap=fibermap[start:end], \
                    meta=dict(CAMERA=camera, FLAVOR=simspec.flavor) )
                desispec.io.write_frame(framefileName, frame)

                framefilePath=desispec.io.findfile("frame",NIGHT,EXPID,camera)
                log.info("Wrote file {}".format(framefilePath))

                if args.frameonly or simspec.flavor == 'arc':
                    continue

                # Write cframe file
                cframeFileName=desispec.io.findfile("cframe",NIGHT,EXPID,camera)
                cframeFlux=cframe_observedflux[start:end,armName[channel],:num_pixels]+cframe_rand_noise[start:end,armName[channel],:num_pixels]
                cframeIvar=cframe_ivar[start:end,armName[channel],:num_pixels]

                # must create desispec.Frame object
                cframe = Frame(waves[channel], cframeFlux, cframeIvar, \
                    resolution_data=resol, spectrograph=ii,
                    fibermap=fibermap[start:end],
                    meta=dict(CAMERA=camera, FLAVOR=simspec.flavor) )
                desispec.io.frame.write_frame(cframeFileName,cframe)

                cframefilePath=desispec.io.findfile("cframe",NIGHT,EXPID,camera)
                log.info("Wrote file {}".format(cframefilePath))

                # Write sky file
                skyfileName=desispec.io.findfile("sky",NIGHT,EXPID,camera)
                skyflux=nsky[start:end,armName[channel],:num_pixels] + \
                sky_rand_noise[start:end,armName[channel],:num_pixels]
                skyivar=sky_ivar[start:end,armName[channel],:num_pixels]
                skymask=np.zeros(skyflux.shape, dtype=np.uint32)

                # must create desispec.Sky object
                skymodel = SkyModel(waves[channel], skyflux, skyivar, skymask,
                    header=dict(CAMERA=camera))
                desispec.io.sky.write_sky(skyfileName, skymodel)

                skyfilePath=desispec.io.findfile("sky",NIGHT,EXPID,camera)
                log.info("Wrote file {}".format(skyfilePath))

                # Write calib file
                calibVectorFile=desispec.io.findfile("calib",NIGHT,EXPID,camera)
                flux = cframe_observedflux[start:end,armName[channel],:num_pixels]
                phot = nobj[start:end,armName[channel],:num_pixels]
                calibration = np.zeros_like(phot)
                jj = (flux>0)
                calibration[jj] = phot[jj] / flux[jj]

                #- TODO: what should calibivar be?
                #- For now, model it as the noise of combining ~10 spectra
                calibivar=10/cframe_ivar[start:end,armName[channel],:num_pixels]
                #mask=(1/calibivar>0).astype(int)??
                mask=np.zeros(calibration.shape, dtype=np.uint32)

                # write flux calibration
                fluxcalib = FluxCalib(waves[channel], calibration, calibivar, mask)
                write_flux_calibration(calibVectorFile, fluxcalib)

                calibfilePath=desispec.io.findfile("calib",NIGHT,EXPID,camera)
                log.info("Wrote file {}".format(calibfilePath))