def __init__(self, path, snapfile):
""" """
# potential used for the simulation
self.potential = LawMajewski2010()
# some smart pathness
if not os.path.exists(path):
_path = os.path.join(streamspath, "data", "simulation", path)
if os.path.exists(_path):
path = _path
else:
raise IOError("Path '{}' doesn't exist".format(path))
self.path = path
self.reader = SCFReader(self.path)
self.particle_table = self.reader.read_snap(snapfile, units=usys)
self.units = _usys
# get mass column from table
m = np.array(self.particle_table['m']) * self.particle_table['m'].unit
self.mass = np.sum(m)
self.t1 = self.particle_table.meta["time"]
self.t2 = 0.
def __init__(self, path, snapfile):
""" """
# potential used for the simulation
self.potential = LawMajewski2010()
# some smart pathness
if not os.path.exists(path):
_path = os.path.join(streamspath, "data", "simulation", path)
if os.path.exists(_path):
path = _path
else:
raise IOError("Path '{}' doesn't exist".format(path))
self.path = path
self.reader = SCFReader(self.path)
self.particle_table = self.reader.read_snap(snapfile, units=usys)
self.units = _usys
# get mass column from table
m = np.array(self.particle_table['m'])*self.particle_table['m'].unit
self.mass = np.sum(m)
self.t1 = self.particle_table.meta["time"]
self.t2 = 0.
def observe_simulation(star_error_model=None,
progenitor_error_model=None,
selection_expr=None,
output_file=None,
overwrite=False,
seed=None,
simulation_path=None,
snapfile=None):
""" Observe simulation data and write the output to an HDF5 file """
if os.path.exists(output_file) and overwrite:
os.remove(output_file)
if os.path.exists(output_file):
raise IOError("File '{}' already exists! Did you "
"want to use overwrite=True?".format(output_file))
# read the simulation data from the specified class
if seed is None:
seed = np.random.randint(100)
logger.debug("Using seed: {}".format(seed))
np.random.seed(seed)
random.seed(seed)
scf = SCFReader(simulation_path)
snap_data = scf.read_snap(snapfile, units=usys)
# select out particles that meet these cuts
idx = numexpr.evaluate("(tub!=0)", snap_data)
star_data = snap_data[idx]
logger.debug("Read in {} particles".format(len(star_data)))
# coordinate transform
star_gc = np.vstack([star_data[n] for n in galactocentric_names]).T
star_hel = gal_to_hel(star_gc)
# create table for star data
star_tbl = at.Table(star_hel, names=heliocentric_names)
star_tbl.add_column(star_data["tub"]) # add tub
# select bound particles to median to get satellite position
idx = numexpr.evaluate("(tub==0)", snap_data)
prog_data = snap_data[idx]
# coordinate transform
prog_gc = np.vstack([prog_data[n] for n in galactocentric_names]).T
prog_gc = np.median(prog_gc, axis=0).reshape(1, 6)
logger.debug("Used {} particles to estimate progenitor position.".format(
len(prog_data)))
prog_hel = gal_to_hel(prog_gc)
# create table for progenitor data
prog_tbl = at.Table(prog_hel, names=heliocentric_names)
prog_tbl.add_column(at.Column([snap_data["m"].sum()],
name="m0")) # add mass
# determine tail assignment for stars by relative energy
dE = energy(star_gc) - energy(prog_gc)
tail = np.zeros(len(star_tbl))
lead = dE <= 0.
trail = dE > 0.
tail[lead] = -1. # leading tail
tail[trail] = 1. # trailing
star_tbl.add_column(at.Column(tail, name="tail")) # add tail
# observe the data
observed_star_tbl, star_err_tbl = observe_table(star_tbl, star_error_model)
observed_prog_tbl, prog_err_tbl = observe_table(prog_tbl,
progenitor_error_model)
# make a plot of true and observed positions
obs_hel = np.vstack([observed_star_tbl[n] for n in heliocentric_names]).T
obs_gc = hel_to_gal(obs_hel)
fig, axes = plt.subplots(2, 2, figsize=(16, 16))
mpl = dict(markersize=3., marker='o', linestyle='none', alpha=0.5)
axes[0, 0].plot(star_gc[:, 0], star_gc[:, 1], **mpl)
axes[0, 1].plot(star_gc[:, 0], star_gc[:, 2], **mpl)
axes[0, 0].plot(obs_gc[trail, 0],
obs_gc[trail, 1],
label='trailing',
c='#ca0020',
**mpl)
axes[0, 1].plot(obs_gc[trail, 0], obs_gc[trail, 2], c='#ca0020', **mpl)
axes[0, 0].plot(obs_gc[lead, 0], obs_gc[lead, 1], label='leading', **mpl)
axes[0, 1].plot(obs_gc[lead, 0], obs_gc[lead, 2], **mpl)
axes[0, 0].legend()
axes[1, 0].plot(star_gc[:, 3], star_gc[:, 4], **mpl)
axes[1, 1].plot(star_gc[:, 3], star_gc[:, 5], **mpl)
axes[1, 0].plot(obs_gc[trail, 3], obs_gc[trail, 4], c='#ca0020', **mpl)
axes[1, 1].plot(obs_gc[trail, 3], obs_gc[trail, 5], c='#ca0020', **mpl)
axes[1, 0].plot(obs_gc[lead, 3], obs_gc[lead, 4], **mpl)
axes[1, 1].plot(obs_gc[lead, 3], obs_gc[lead, 5], **mpl)
fname = os.path.splitext(os.path.basename(output_file))[0]
fig.savefig(
os.path.join(
os.path.split(output_file)[0], "{}.{}".format(fname, 'png')))
# write tables to output_file
observed_star_tbl.write(output_file,
format="hdf5",
path="stars",
overwrite=overwrite)
observed_prog_tbl.write(output_file,
format="hdf5",
path="progenitor",
append=True)
star_err_tbl.write(output_file,
format="hdf5",
path="error_stars",
append=True)
prog_err_tbl.write(output_file,
format="hdf5",
path="error_progenitor",
append=True)
star_tbl.write(output_file, format="hdf5", path="true_stars", append=True)
prog_tbl.write(output_file,
format="hdf5",
path="true_progenitor",
append=True)
integ_tbl = at.Table(np.array([[np.nan]]))
integ_tbl.meta['t1'] = snap_data.meta['time']
integ_tbl.meta['t2'] = 0.
integ_tbl.write(output_file,
format="hdf5",
path="integration",
append=True)
def observe_simulation(star_error_model=None, progenitor_error_model=None,
selection_expr=None, output_file=None, overwrite=False,
seed=None, simulation_path=None, snapfile=None):
""" Observe simulation data and write the output to an HDF5 file """
if os.path.exists(output_file) and overwrite:
os.remove(output_file)
if os.path.exists(output_file):
raise IOError("File '{}' already exists! Did you "
"want to use overwrite=True?".format(output_file))
# read the simulation data from the specified class
if seed is None:
seed = np.random.randint(100)
logger.debug("Using seed: {}".format(seed))
np.random.seed(seed)
random.seed(seed)
scf = SCFReader(simulation_path)
snap_data = scf.read_snap(snapfile, units=usys)
# select out particles that meet these cuts
idx = numexpr.evaluate("(tub!=0)", snap_data)
star_data = snap_data[idx]
logger.debug("Read in {} particles".format(len(star_data)))
# coordinate transform
star_gc = np.vstack([star_data[n] for n in galactocentric_names]).T
star_hel = gal_to_hel(star_gc)
# create table for star data
star_tbl = at.Table(star_hel, names=heliocentric_names)
star_tbl.add_column(star_data["tub"]) # add tub
# select bound particles to median to get satellite position
idx = numexpr.evaluate("(tub==0)", snap_data)
prog_data = snap_data[idx]
# coordinate transform
prog_gc = np.vstack([prog_data[n] for n in galactocentric_names]).T
prog_gc = np.median(prog_gc, axis=0).reshape(1,6)
logger.debug("Used {} particles to estimate progenitor position.".format(len(prog_data)))
prog_hel = gal_to_hel(prog_gc)
# create table for progenitor data
prog_tbl = at.Table(prog_hel, names=heliocentric_names)
prog_tbl.add_column(at.Column([snap_data["m"].sum()], name="m0")) # add mass
# determine tail assignment for stars by relative energy
dE = energy(star_gc) - energy(prog_gc)
tail = np.zeros(len(star_tbl))
lead = dE <= 0.
trail = dE > 0.
tail[lead] = -1. # leading tail
tail[trail] = 1. # trailing
star_tbl.add_column(at.Column(tail, name="tail")) # add tail
# observe the data
observed_star_tbl,star_err_tbl = observe_table(star_tbl, star_error_model)
observed_prog_tbl,prog_err_tbl = observe_table(prog_tbl, progenitor_error_model)
# make a plot of true and observed positions
obs_hel = np.vstack([observed_star_tbl[n] for n in heliocentric_names]).T
obs_gc = hel_to_gal(obs_hel)
fig,axes = plt.subplots(2,2,figsize=(16,16))
mpl = dict(markersize=3., marker='o', linestyle='none', alpha=0.5)
axes[0,0].plot(star_gc[:,0], star_gc[:,1], **mpl)
axes[0,1].plot(star_gc[:,0], star_gc[:,2], **mpl)
axes[0,0].plot(obs_gc[trail,0], obs_gc[trail,1], label='trailing', c='#ca0020', **mpl)
axes[0,1].plot(obs_gc[trail,0], obs_gc[trail,2], c='#ca0020', **mpl)
axes[0,0].plot(obs_gc[lead,0], obs_gc[lead,1], label='leading', **mpl)
axes[0,1].plot(obs_gc[lead,0], obs_gc[lead,2], **mpl)
axes[0,0].legend()
axes[1,0].plot(star_gc[:,3], star_gc[:,4], **mpl)
axes[1,1].plot(star_gc[:,3], star_gc[:,5], **mpl)
axes[1,0].plot(obs_gc[trail,3], obs_gc[trail,4], c='#ca0020', **mpl)
axes[1,1].plot(obs_gc[trail,3], obs_gc[trail,5], c='#ca0020', **mpl)
axes[1,0].plot(obs_gc[lead,3], obs_gc[lead,4], **mpl)
axes[1,1].plot(obs_gc[lead,3], obs_gc[lead,5], **mpl)
fname = os.path.splitext(os.path.basename(output_file))[0]
fig.savefig(os.path.join(os.path.split(output_file)[0],
"{}.{}".format(fname, 'png')))
# write tables to output_file
observed_star_tbl.write(output_file, format="hdf5", path="stars", overwrite=overwrite)
observed_prog_tbl.write(output_file, format="hdf5", path="progenitor", append=True)
star_err_tbl.write(output_file, format="hdf5", path="error_stars", append=True)
prog_err_tbl.write(output_file, format="hdf5", path="error_progenitor", append=True)
star_tbl.write(output_file, format="hdf5", path="true_stars", append=True)
prog_tbl.write(output_file, format="hdf5", path="true_progenitor", append=True)
integ_tbl = at.Table(np.array([[np.nan]]))
integ_tbl.meta['t1'] = snap_data.meta['time']
integ_tbl.meta['t2'] = 0.
integ_tbl.write(output_file, format="hdf5", path="integration", append=True)
class SgrSimulation(object):
def __init__(self, path, snapfile):
""" """
# potential used for the simulation
self.potential = LawMajewski2010()
# some smart pathness
if not os.path.exists(path):
_path = os.path.join(streamspath, "data", "simulation", path)
if os.path.exists(_path):
path = _path
else:
raise IOError("Path '{}' doesn't exist".format(path))
self.path = path
self.reader = SCFReader(self.path)
self.particle_table = self.reader.read_snap(snapfile, units=usys)
self.units = _usys
# get mass column from table
m = np.array(self.particle_table['m']) * self.particle_table['m'].unit
self.mass = np.sum(m)
self.t1 = self.particle_table.meta["time"]
self.t2 = 0.
def particles(self, n=None, expr=None, tail_bit=False, clean=False):
""" Return a Particle object with N particles selected from the
simulation with expression expr.
Parameters
----------
n : int or None (optional)
Number of particles to return. None or 0 means 'all'
expr : str (optional)
Use numexpr to select out only rows that match criteria.
tail_bit : bool (optional)
Compute tail bit or not.
"""
if expr is not None:
expr_idx = numexpr.evaluate(str(expr), self.particle_table)
else:
expr_idx = np.ones(len(self.particle_table)).astype(bool)
table = self.particle_table[expr_idx]
n_idx = np.array(sample(xrange(len(table)), len(table)))
if n is not None and n > 0:
idx = n_idx[:n]
else:
idx = n_idx
table = table[idx]
# get a list of quantities for each column
coords = []
for colname in galactocentric.coord_names:
coords.append(np.array(table[colname]) * table[colname].unit)
meta = dict(expr=expr)
meta["tub"] = (np.array(table["tub"]) * table["tub"].unit).to(
_usys["time"]).value
# create the particle object
p = Particle(coords, frame=galactocentric, meta=meta)
p = p.decompose(usys)
# guess whether in leading or trailing tail
if tail_bit:
coord, r_tide, v_disp = particles_x1x2x3(p,
self.satellite(),
self.potential,
self.t1,
self.t2,
-1,
at_tub=True)
(x1, x2, x3, vx1, vx2, vx3) = coord
p.meta["tail_bit"] = p.tail_bit = guess_tail_bit(x1, x2)
else:
tail_bit = np.ones(p.nparticles) * np.nan
if clean:
if not tail_bit:
coord, r_tide, v_disp = particles_x1x2x3(p,
self.satellite(),
self.potential,
self.t1,
self.t2,
-1,
at_tub=True)
(x1, x2, x3, vx1, vx2, vx3) = coord
tail_bit = guess_tail_bit(x1, x2)
else:
tail_bit = p.tail_bit
# reject any with nan tail_bit
idx = ~np.isnan(tail_bit)
# reject any with |x1| > 2.5 or |x2| > 1.2
idx &= np.fabs(x1 / r_tide) < 2.5
idx &= np.fabs(x2 / r_tide) < 1.2
_X = p._X[idx]
meta["tub"] = p.tub[idx]
meta["tail_bit"] = tail_bit[idx]
p = Particle(_X.T.copy(),
frame=p.frame,
units=p._internal_units,
meta=meta)
return p
def satellite(self):
""" Return a Particle object with the present-day position of the
satellite, computed from the still-bound particles.
"""
expr_idx = numexpr.evaluate("tub==0", self.particle_table)
bound = self.particle_table[expr_idx]
q = []
for colname in galactocentric.coord_names:
q.append(np.median(np.array(bound[colname])) * bound[colname].unit)
meta = dict()
meta["m0"] = self.mass.to(_usys['mass']).value
mdot = 3.3 * 10**(np.floor(np.log10(meta["m0"])) - 4)
meta['mdot'] = mdot
p = Particle(q, frame=galactocentric, meta=meta)
return p.decompose(usys)
class SgrSimulation(object):
def __init__(self, path, snapfile):
""" """
# potential used for the simulation
self.potential = LawMajewski2010()
# some smart pathness
if not os.path.exists(path):
_path = os.path.join(streamspath, "data", "simulation", path)
if os.path.exists(_path):
path = _path
else:
raise IOError("Path '{}' doesn't exist".format(path))
self.path = path
self.reader = SCFReader(self.path)
self.particle_table = self.reader.read_snap(snapfile, units=usys)
self.units = _usys
# get mass column from table
m = np.array(self.particle_table['m'])*self.particle_table['m'].unit
self.mass = np.sum(m)
self.t1 = self.particle_table.meta["time"]
self.t2 = 0.
def particles(self, n=None, expr=None, tail_bit=False, clean=False):
""" Return a Particle object with N particles selected from the
simulation with expression expr.
Parameters
----------
n : int or None (optional)
Number of particles to return. None or 0 means 'all'
expr : str (optional)
Use numexpr to select out only rows that match criteria.
tail_bit : bool (optional)
Compute tail bit or not.
"""
if expr is not None:
expr_idx = numexpr.evaluate(str(expr), self.particle_table)
else:
expr_idx = np.ones(len(self.particle_table)).astype(bool)
table = self.particle_table[expr_idx]
n_idx = np.array(sample(xrange(len(table)), len(table)))
if n is not None and n > 0:
idx = n_idx[:n]
else:
idx = n_idx
table = table[idx]
# get a list of quantities for each column
coords = []
for colname in galactocentric.coord_names:
coords.append(np.array(table[colname])*table[colname].unit)
meta = dict(expr=expr)
meta["tub"] = (np.array(table["tub"])*table["tub"].unit).to(_usys["time"]).value
# create the particle object
p = Particle(coords, frame=galactocentric, meta=meta)
p = p.decompose(usys)
# guess whether in leading or trailing tail
if tail_bit:
coord, r_tide, v_disp = particles_x1x2x3(p, self.satellite(),
self.potential,
self.t1, self.t2, -1,
at_tub=True)
(x1,x2,x3,vx1,vx2,vx3) = coord
p.meta["tail_bit"] = p.tail_bit = guess_tail_bit(x1,x2)
else:
tail_bit = np.ones(p.nparticles)*np.nan
if clean:
if not tail_bit:
coord, r_tide, v_disp = particles_x1x2x3(p, self.satellite(),
self.potential,
self.t1, self.t2, -1,
at_tub=True)
(x1,x2,x3,vx1,vx2,vx3) = coord
tail_bit = guess_tail_bit(x1,x2)
else:
tail_bit = p.tail_bit
# reject any with nan tail_bit
idx = ~np.isnan(tail_bit)
# reject any with |x1| > 2.5 or |x2| > 1.2
idx &= np.fabs(x1/r_tide) < 2.5
idx &= np.fabs(x2/r_tide) < 1.2
_X = p._X[idx]
meta["tub"] = p.tub[idx]
meta["tail_bit"] = tail_bit[idx]
p = Particle(_X.T.copy(), frame=p.frame, units=p._internal_units, meta=meta)
return p
def satellite(self):
""" Return a Particle object with the present-day position of the
satellite, computed from the still-bound particles.
"""
expr_idx = numexpr.evaluate("tub==0", self.particle_table)
bound = self.particle_table[expr_idx]
q = []
for colname in galactocentric.coord_names:
q.append(np.median(np.array(bound[colname]))*bound[colname].unit)
meta = dict()
meta["m0"] = self.mass.to(_usys['mass']).value
mdot = 3.3*10**(np.floor(np.log10(meta["m0"]))-4)
meta['mdot'] = mdot
p = Particle(q, frame=galactocentric, meta=meta)
return p.decompose(usys)
