def table(self):
"""An :class:`astropy.table.Table` with the chain."""
msuns = np.array([fsps.get_filter(n).msun_ab
for n in self._model.computed_bands])
theta_f_accept = json.dumps(dict(zip(self._model.theta_params,
self.median_theta_faccept)))
phi_f_accept = json.dumps(dict(zip(self._model.phi_params,
self.phi_faccept)))
meta = OrderedDict((
('theta_f_accept', theta_f_accept),
('phi_f_accept', phi_f_accept),
('observed_bands', self._model.observed_bands),
('instruments', self._model.instruments),
('computed_bands', self._model.computed_bands),
('msun_ab', msuns),
('band_indices', self._model.band_indices),
('theta_params', self._model.theta_params),
('phi_params', self._model.phi_params),
('theta_proposal_sigma', self._theta_prop),
('phi_proposal_sigma', self._theta_prop),
('sed', self._model._seds),
('sed_err', self._model._errs),
('pixels', self._model.pixel_metadata),
('area', self._model._areas)))
# Make tables for individual chains; stack later
# FIXME should axis order be changed for theta throughout the sampler?
# or I can just continue to swarp aces here
theta_table = Table(np.swapaxes(self.theta, 1, 2),
names=self._model.theta_params,
meta=meta)
phi_table = Table(self.phi, names=self._model.phi_params)
background_names = ["B__{0}__{1}".format(n, b)
for n, b in zip(self._model.instruments,
self._model.observed_bands)]
B_table = Table(self.B, names=background_names)
blob_table = Table(self.blobs)
tbl = MultiPixelChain(hstack((theta_table,
phi_table,
B_table,
blob_table)))
# Add M/L computations for each computed band.
for i, (band_name, msun) in enumerate(zip(self._model.computed_bands,
msuns)):
logLsol = micro_jy_to_luminosity(tbl['model_sed'][:, :, i],
msun,
np.atleast_2d(tbl['d']).T)
ml = tbl['logMstar'] - logLsol
colname = "logML_{0}".format(band_name)
tbl.add_column(Column(name=colname, data=ml))
return tbl
def compute_library_seds(self, bands, age=13.7, default_pset=None):
"""Compute an SED for each library model instance.
Model SEDs are stored as absolute fluxes (µJy at d=10pc), normalized
to a 1 Solar mass stellar population.
.. todo:: Support parallel computation.
Parameters
----------
bands : list
List of `FSPS bandpass names
<http://dan.iel.fm/python-fsps/current/filters/>`_.
default_pset : dict
Default Python-FSPS parameters.
"""
if default_pset is None:
default_pset = {}
# ALWAYS compute AB mags
default_pset['compute_vega_mags'] = False
# Solar magnitude in each bandpass
solar_mags = [fsps.get_filter(n).msun_ab for n in bands]
# Add bands and AB solar mags to the group attr metadata
self.group.attrs['bands'] = bands
self.group.attrs['msun_ab'] = solar_mags
# Build the SED table
table_names = ['seds', 'mass_light', 'meta']
for name in table_names:
if name in self.group:
del self.group[name]
# Table for SEDs
n_models = len(self.group["params"])
dtype = np.dtype([(n, np.float) for n in bands])
sed_table = self.group.create_dataset("seds",
(n_models,),
dtype=dtype)
# Table for M/L ratios in each bandpass
dtype = np.dtype([(n, np.float) for n in bands])
ml_table = self.group.create_dataset("mass_light",
(n_models,),
dtype=dtype)
# Table for metadata (stellar mass, dust mass, etc..)
meta_cols = ('logMstar', 'logMdust', 'logLbol', 'logSFR', 'logAge')
dtype = np.dtype([(n, np.float) for n in meta_cols])
meta_table = self.group.create_dataset("meta",
(n_models,),
dtype=dtype)
# Iterate on each model
# TODO eventually split this work between processors
sp_param_names = self.group['params'].dtype.names
sp = fsps.StellarPopulation(**default_pset)
for i, row in enumerate(self.group["params"]):
for n, p in zip(sp_param_names, row):
sp.params[n] = float(p)
mags = sp.get_mags(tage=age, bands=bands)
fluxes = abs_ab_mag_to_micro_jy(mags, 10.)
# Fill in SED and ML tables
for n, msun, flux in zip(bands, solar_mags, fluxes):
# interesting slicing syntax for structured array assignment
sed_table[n, i] = flux
logL = micro_jy_to_luminosity(flux, msun, 10.)
log_ml = np.log10(sp.stellar_mass) - logL
ml_table[n, i] = log_ml
# Fill in meta data table
meta_table['logMstar', i] = np.log10(sp.stellar_mass)
meta_table['logMdust', i] = np.log10(sp.dust_mass)
meta_table['logLbol', i] = np.log10(sp.log_lbol)
meta_table['logSFR', i] = np.log10(sp.sfr)
meta_table['logAge', i] = sp.log_age
def table(self):
"""An :class:`astropy.table.Table` with the chain."""
if self.sampler is None:
return None
msuns = np.array([fsps.get_filter(n).msun_ab
for n in self.model.computed_bands])
meta = OrderedDict((
('observed_bands', self.model.observed_bands),
('instruments', self.model.instruments),
('computed_bands', self.model.computed_bands),
('msun_ab', msuns),
('d', self.model.d), # expected distance in parsecs
('band_indices', self.model.band_indices),
('theta_params', self.model.param_names),
('compute_time', self._run_time),
('step_time', self._call_time),
('sed', self.model._sed),
('sed_err', self.model._err),
('pixels', self.model.pixel_metadata),
('area', self.model._area),
('n_walkers', self.n_walkers),
("f_accept", self.sampler.acceptance_fraction),
("acor", self.sampler.acor)))
# Convert flatchain into a structured array
nwalkers, nsteps, ndim = self.sampler.chain.shape
flatchain_arr = self.sampler.chain[:, :, :].reshape((-1, ndim))
dt = [(n, np.float) for n in self.model.param_names]
flatchain = np.empty(flatchain_arr.shape[0], dtype=np.dtype(dt))
for i, n in enumerate(self.model.param_names):
flatchain[n][:] = flatchain_arr[:, i]
# Flatten the blob list and make a structured array
blobs = self.sampler.blobs
blobchain = np.empty(nwalkers * nsteps, self.model.blob_dtype)
blobchain.fill(np.nan)
for i in xrange(nsteps):
for j in xrange(nwalkers):
for k in self.model.blob_dtype.names:
blobchain[k][i * self.n_walkers + j] = blobs[i][j][k]
chain_table = Table(flatchain, meta=meta)
blob_table = Table(blobchain)
tbl = SinglePixelChain(hstack((chain_table, blob_table),
join_type='exact'))
# Add M/L computations for each computed band.
for i, (band_name, msun) in enumerate(zip(self.model.computed_bands,
msuns)):
# Either use expected distance or the chain distance
# FIXME fragile code
if 'd' in self.model.param_names:
d = np.array(tbl['d'])
else:
d = self.model.d
logLsol = micro_jy_to_luminosity(tbl['model_sed'][:, i], msun, d)
ml = tbl['logMstar'] - logLsol
colname = "logML_{0}".format(band_name)
tbl.add_column(Column(name=colname, data=ml))
return tbl
