def __init_spline(self, knots, coeffs, deg, units=None):
if not isinstance(knots, ureg.Quantity):
if units is None:
knots = knots * ureg.dimensionless
else:
knots = ureg.Quantity(np.asarray(knots), units)
self._state_attrs.extend(['knots', 'coeffs', 'deg', 'units'])
self.kind = 'spline'
if isinstance(knots, ureg.Quantity):
self.units = str(knots.units)
self.knots = knots
self.coeffs = coeffs
self.deg = deg
def llh(x):
x = self.__strip(self.__convert(x))
return splev(x, tck=(self.__strip(self.knots), coeffs, deg), ext=2)
self.llh = llh
self.max_at = fminbound(
func=self.__attach_units_to_args(self.chi2),
x1=np.min(self.__strip(self.knots)),
x2=np.max(self.__strip(self.knots)),
)
if self.units is not None:
self.max_at = self.max_at * ureg(self.units)
self.max_at_str = self.__stringify(self.max_at)
self.valid_range = (np.min(self.knots) * ureg(self.units),
np.max(self.knots) * ureg(self.units))
self._str = lambda s: 'spline prior: deg=%d, valid in [%s, %s]%s; max at %s%s' \
%(self.deg, self.__stringify(np.min(self.knots)),
self.__stringify(np.max(self.knots)), self.units_str,
self.max_at_str, self.units_str)
def __init_spline(self, knots, coeffs, deg, units=None):
knots = interpret_quantity(knots, expect_sequence=True)
self._state_attrs.extend(['knots', 'coeffs', 'deg'])
self.kind = 'spline'
if isunitless(knots):
knots = ureg.Quantity(knots, units)
elif units is not None:
units = ureg.Unit(units)
assert knots.dimensionality == units.dimensionality
knots = knots.to(units)
self.units = str(knots.units)
self.knots = knots
self.coeffs = coeffs
self.deg = deg
def llh(x):
x = self.__strip(self.__convert(x))
return splev(x, tck=(self.__strip(self.knots), coeffs, deg), ext=2)
self.llh = llh
self.max_at = fminbound(
func=self.__attach_units_to_args(self.chi2),
x1=np.min(self.__strip(self.knots)),
x2=np.max(self.__strip(self.knots)),
)
if self.units is not None:
self.max_at = self.max_at * ureg(self.units)
self.max_at_str = self.__stringify(self.max_at)
self.valid_range = (np.min(self.knots) * ureg(self.units),
np.max(self.knots) * ureg(self.units))
self._str = lambda s: 'spline prior: deg=%d, valid in [%s, %s]%s; max at %s%s' \
%(self.deg, self.__stringify(np.min(self.knots)),
self.__stringify(np.max(self.knots)), self.units_str,
self.max_at_str, self.units_str)
def parse_param(config, section, selector, fullname, pname, value):
"""Parse a param specification from a PISA config file.
Note that if the param sepcification does not include ``fixed``,
``prior``, and/or ``range``, the defaults for these are:
``fixed = True``, ``prior = None``, and ``range = None``.
If a prior is specified explicitly via ``.prior``, this takes precendence,
but if no ``.prior`` is specified and the param's value is parsed to be a
:class:`uncertainties.AffineScalarFunc` (i.e. have `std_dev` attribute), a
Gaussian prior is constructed from that and then the AffineScalarFunc is
stripped out of the param's value (such that it is just a
:class:`~pint.quantity.Quantity`).
Parameters
----------
config : pisa.utils.config_parser.PISAConfigParser
section : string
selector : string or None
fullname : string
pname : string
value : string
Returns
-------
param : pisa.core.param.Param
"""
# Note: imports placed here to avoid circular imports
from pisa.core.param import Param
from pisa.core.prior import Prior
kwargs = dict(name=pname, is_fixed=True, prior=None, range=None)
try:
value = parse_quantity(value)
kwargs['value'] = value.nominal_value * value.units
except ValueError:
value = parse_string_literal(value)
kwargs['value'] = value
# Search for explicit attr specifications
if config.has_option(section, fullname + '.fixed'):
kwargs['is_fixed'] = config.getboolean(section, fullname + '.fixed')
if config.has_option(section, fullname + '.unique_id'):
kwargs['unique_id'] = config.get(section, fullname + '.unique_id')
if config.has_option(section, fullname + '.range'):
range_ = config.get(section, fullname + '.range')
# Note: `nominal` and `sigma` are called out in the `range_` string
if 'nominal' in range_:
nominal = value.n * value.units # pylint: disable=unused-variable
if 'sigma' in range_:
sigma = value.s * value.units # pylint: disable=unused-variable
range_ = range_.replace('[', 'np.array([')
range_ = range_.replace(']', '])')
# Strip out uncertainties from value itself (as we will rely on the
# prior from here on out)
kwargs['range'] = eval(range_).to(value.units) # pylint: disable=eval-used
if config.has_option(section, fullname + '.prior'):
prior = str(config.get(section, fullname + '.prior')).strip().lower()
if prior == 'uniform':
kwargs['prior'] = Prior(kind='uniform')
elif prior == 'jeffreys':
kwargs['prior'] = Prior(kind='jeffreys',
A=kwargs['range'][0],
B=kwargs['range'][1])
elif prior == 'spline':
priorname = pname
if selector is not None:
priorname += '_' + selector
data = config.get(section, fullname + '.prior.data')
data = from_file(data)
data = data[priorname]
knots = ureg.Quantity(np.asarray(data['knots']), data['units'])
knots = knots.to(value.units)
coeffs = np.asarray(data['coeffs'])
deg = data['deg']
kwargs['prior'] = Prior(kind='spline',
knots=knots,
coeffs=coeffs,
deg=deg)
elif prior == 'none':
kwargs['prior'] = None
elif 'gauss' in prior:
raise Exception('Please use new style +/- notation for gaussian'
' priors in config')
else:
raise Exception('Prior type unknown')
elif hasattr(value, 'std_dev') and value.std_dev != 0:
kwargs['prior'] = Prior(kind='gaussian',
mean=value.nominal_value * value.units,
stddev=value.std_dev * value.units)
# Strip out any uncertainties from value itself (an explicit ``.prior``
# specification takes precedence over this)
if hasattr(value, 'std_dev'):
value = value.nominal_value * value.units
try:
param = Param(**kwargs)
except:
logging.error('Failed to instantiate new Param object with kwargs %s',
kwargs)
raise
return param
def get_prior_bounds(obj, param=None, stddev=1.0):
"""Obtain confidence regions for CL corresponding to given number of
stddevs from parameter prior.
Parameters
----------
obj : string or Mapping
if str, interpret as path from which to load a dict
if dict, can be:
template settings dict; must supply `param` to choose which to plot
params dict; must supply `param` to choose which to plot
prior dict
param : Param
Name of param for which to get bounds;
necessary if obj is either template settings or params
stddev : float or Iterable of floats
number of stddevs
Returns
-------
bounds : OrderedDict
A dictionary mapping the passed `stddev` values to the corresponding
bounds
"""
if isbarenumeric(stddev):
stddev = [stddev]
elif isinstance(stddev, Iterable):
stddev = list(stddev)
bounds = OrderedDict()
for s in stddev:
bounds[s] = []
if isinstance(obj, basestring):
obj = from_file(obj)
if 'params' in obj:
obj = obj['params']
if param is not None and param in obj:
obj = obj[param]
if 'prior' in obj:
obj = obj['prior']
prior = Prior(**obj)
logging.debug('Getting confidence region from prior: %s', prior)
x0 = prior.valid_range[0]
x1 = prior.valid_range[1]
x = ureg.Quantity(np.linspace(x0, x1, 10000), prior.units)
chi2 = prior.chi2(x)
for (i, xval) in enumerate(x[:-1]):
for s in stddev:
chi2_level = s**2
if chi2[i] > chi2_level and chi2[i + 1] < chi2_level:
bounds[s].append(xval)
elif chi2[i] < chi2_level and chi2[i + 1] > chi2_level:
bounds[s].append(x[i + 1])
return bounds
def plot_prior(obj,
param=None,
x_xform=None,
ax1=None,
ax2=None,
**plt_kwargs):
"""Plot prior for param from template settings, params, or prior filename
or dict.
Arguments
---------
obj : str or dict
if str, interpret as path from which to load a dict
if (nested) dict, (innermost) must be dict of prior properties :
either supply `param` to choose which parameter's prior in `obj`
to plot, or prior dict, in which case `param` need not be specified
param
Param name to plot; necessary if obj is either pipeline settings or
params dict
x_xform
Transform to apply to x-values. E.g., to plot against sin^2 theta, use
x_xform = lambda x: np.sin(x)**2
ax1, ax2
Axes onto which to plot LLH and chi-squared, respectively. If none are
provided, new figures & axes will be created.
plt_kwargs
Keyword arguments to pass on to the plot function
Returns
-------
ax1, ax2
The axes onto which plots were drawn (ax1 = LLH, ax2 = chi^2)
"""
import matplotlib as mpl
mpl.use('pdf')
import matplotlib.pyplot as plt
if isinstance(obj, basestring):
obj = from_file(obj)
if param is not None and param in obj:
obj = obj[param]
if 'prior' in obj:
obj = obj['prior']
prior = Prior(**obj)
logging.info('Plotting Prior: %s', prior)
x0 = prior.valid_range[0]
x1 = prior.valid_range[1]
if prior.kind == 'gaussian':
x0 = max(x0, prior.max_at - 5 * prior.stddev)
x1 = min(x1, prior.max_at + 5 * prior.stddev)
if np.isinf(x0):
x0 = -1
if np.isinf(x1):
x1 = +1
# if prior.units is None, will result in dimensionless quantity
x = ureg.Quantity(np.linspace(x0, x1, 5000), prior.units)
llh = prior.llh(x)
chi2 = prior.chi2(x)
if x_xform is not None:
x = x_xform(x)
if ax1 is None:
f = plt.figure()
ax1 = f.add_subplot(111)
if ax2 is None:
f = plt.figure()
ax2 = f.add_subplot(111)
ax1.plot(x, llh, **plt_kwargs)
ax2.plot(x, chi2, **plt_kwargs)
ax1.set_title(str(prior), fontsize=8, y=1.02)
ax2.set_title(str(prior), fontsize=8, y=1.02)
ax1.set_xlabel(param)
ax2.set_xlabel(param)
ax1.set_ylabel('LLH')
ax2.set_ylabel(r'$\Delta\chi^2$')
return ax1, ax2
