from __future__ import absolute_import, division, print_function, unicode_literals
import six
from collections import OrderedDict
import numpy as np
import logging
from madminer.utils.interfaces.madminer_hdf5 import (
save_events_to_madminer_file,
load_madminer_settings,
save_nuisance_setup_to_madminer_file,
)
from madminer.utils.interfaces.lhe import parse_lhe_file, extract_nuisance_parameters_from_lhe_file
logger = logging.getLogger(__name__)
[docs]class LHEProcessor:
"""
Detector simulation with smearing functions and simple calculation of observables.
After setting up the parameter space and benchmarks and running MadGraph and Pythia, all of which is organized
in the madminer.core.MadMiner class, the next steps are the simulation of detector effects and the calculation of
observables. Different tools can be used for these tasks, please feel free to implement the detector simulation and
analysis routine of your choice.
This class provides a simple implementation in which detector effects are modeled with smearing functions. Its
workflow consists of the following steps:
* Initializing the class with the filename of a MadMiner HDF5 file (the output of `madminer.core.MadMiner.save()`)
* Adding one or multiple event samples produced by MadGraph and Pythia in `LHEProcessor.add_sample()`.
* Running Delphes on the samples that require it through `LHEProcessor.run_delphes()`.
* Optionally, smearing functions for all visible particles can be defined with
`LHEProcessor.set_smearing()`.
* Defining observables through `LHEProcessor.add_observable()` or
`LHEProcessor.add_observable_from_function()`. A simple set of default observables is provided in
`LHEProcessor.add_default_observables()`
* Optionally, cuts can be set with `LHEProcessor.add_cut()`
* Calculating the observables from the Delphes ROOT files with `LHEProcessor.analyse_delphes_samples()`
* Saving the results with `LHEProcessor.save()`
Please see the tutorial for a detailed walk-through.
Parameters
----------
filename : str or None, optional
Path to MadMiner file (the output of `madminer.core.MadMiner.save()`). Default value: None.
"""
def __init__(self, filename):
# Initialize samples
self.lhe_sample_filenames = []
self.sample_k_factors = []
self.sample_is_backgrounds = []
self.sampling_benchmarks = []
# Initialize observables
self.observables = OrderedDict()
self.observables_required = OrderedDict()
self.observables_defaults = OrderedDict()
# Initialize cuts
self.cuts = []
self.cuts_default_pass = []
# Smearing function parameters
self.energy_resolution = {}
self.pt_resolution = {}
self.eta_resolution = {}
self.phi_resolution = {}
pdgids = [
1,
-1,
2,
-2,
3,
-3,
4,
-4,
5,
-5,
6,
-6,
9,
11,
-11,
12,
-12,
13,
-13,
14,
-14,
15,
-15,
16,
-16,
21,
22,
23,
-23,
24,
25,
]
for pdgid in pdgids:
self.energy_resolution[pdgid] = (0.0, 0.0)
self.pt_resolution[pdgid] = (0.0, 0.0)
self.eta_resolution[pdgid] = (0.0, 0.0)
self.phi_resolution[pdgid] = (0.0, 0.0)
# Initialize samples
self.reference_benchmark = None
self.observations = None
self.weights = None
# Initialize nuisance parameters
self.nuisance_parameters = None
# Information from .h5 file
self.filename = filename
(parameters, benchmarks, _, _, _, _, _, self.systematics, _, _) = load_madminer_settings(
filename, include_nuisance_benchmarks=False
)
self.benchmark_names_phys = list(benchmarks.keys())
self.n_benchmarks_phys = len(benchmarks)
[docs] def add_sample(self, lhe_filename, sampled_from_benchmark, is_background=False, k_factor=1.0):
"""
Adds an LHE sample of simulated events.
Parameters
----------
lhe_filename : str
Path to the LHE event file (with extension '.lhe' or '.lhe.gz').
sampled_from_benchmark : str
Name of the benchmark that was used for sampling in this event file (the keyword `sample_benchmark`
of `madminer.core.MadMiner.run()`).
is_background : bool, optional
Whether the sample is a background sample (i.e. without benchmark reweighting).
k_factor : float, optional
Multiplies the cross sections found in the sample. Default value: 1.
Returns
-------
None
"""
logger.debug("Adding event sample %s", lhe_filename)
# Check inputs
self.sampling_benchmarks.append(sampled_from_benchmark)
self.sample_is_backgrounds.append(is_background)
self.sample_k_factors.append(k_factor)
self.lhe_sample_filenames.append(lhe_filename)
[docs] def set_smearing(
self,
pdgids=None,
energy_resolution_abs=0.0,
energy_resolution_rel=0.0,
pt_resolution_abs=0.0,
pt_resolution_rel=0.0,
eta_resolution_abs=0.0,
eta_resolution_rel=0.0,
phi_resolution_abs=0.0,
phi_resolution_rel=0.0,
):
"""
Sets up the smearing of measured momenta from shower and detector effects.
This function can be called with pdgids=None, in which case the settinigs are used for all visible particles,
or with pdgids set to a list of PDG ids representing particles, for instance [11, -11] for electrons (and
positrons).
For all particles of this type, and for the energy, pT, phi, and eta, the measurement error is drawn from a
Gaussian with mean 0 and standard deviation given by `(X_resolution_abs + X * X_resolution_rel)`. Here `X` is
the quantity (E, pT, phi, eta) of interest and X_resolution_abs and X_resolution_rel are the corresponding
keywords. In the case of energy and pT, values smaller than 0 will lead to a re-drawing of the measurement
error.
Instead of such numerical values, either the energy or pT resolution (but not both!) may be set to None. In
this case, this quantity is calculated from the mass of the particle and all other smeared particles. For
instance, when pt_resolution_abs is None or pt_resolution_rel is None, for the given particles the energy,
phi, and eta are smeared (according to their respective resolutions). Then the transverse momentum is calculated
from the on-shell condition `p^2 = m^2`, or `pT = sqrt(E^2 - m^2) / cosh(eta)`. When this does not have a
solution, the pT is set to zero. On the other hand, when energy_resolution_abs is None or energy_resolution_abs
is None, for the given particles the pT, phi, and eta are smeared, and then the energy is calculated as
`E = sqrt(pT * cosh(eta))^2 + m^2)`.
Parameters
----------
pdgids : None or list of int, optional
Defines the particles these smearing functions affect. If None, all particles are affected. Note that if
set_smearing() is called multiple times for a given particle, the earlier calls will be forgotten and only
the last smearing function will take effect. Default value: None.
energy_resolution_abs : float or None, optional
Absolute measurement uncertainty for the energy in GeV. None means that the energy is not smeared directly, but
calculated from the on-shell condition. Default value: 0.
energy_resolution_rel : float or None, optional
Relative measurement uncertainty for the energy. None means that the energy is not smeared directly, but
calculated from the on-shell condition. Default value: 0.
pt_resolution_abs : float or None, optional
Absolute measurement uncertainty for the pT in GeV. None means that the pT is not smeared directly, but
calculated from the on-shell condition. Default value: 0.
pt_resolution_rel : float or None, optional
Relative measurement uncertainty for the pT. None means that the pT is not smeared directly, but
calculated from the on-shell condition. Default value: 0.
eta_resolution_abs : float, optional
Absolute measurement uncertainty for eta. Default value: 0.
eta_resolution_rel : float, optional
Relative measurement uncertainty for eta. Default value: 0.
phi_resolution_abs : float, optional
Absolute measurement uncertainty for phi. Default value: 0.
phi_resolution_rel : float, optional
Relative measurement uncertainty for phi. Default value: 0.
Returns
-------
None
"""
if pdgids is None:
pdgids = [
1,
-1,
2,
-2,
3,
-3,
4,
-4,
5,
-5,
6,
-6,
9,
11,
-11,
12,
-12,
13,
-13,
14,
-14,
15,
-15,
16,
-16,
21,
22,
23,
-23,
24,
25,
]
for pdgid in pdgids:
self.energy_resolution[pdgid] = (energy_resolution_abs, energy_resolution_rel)
self.pt_resolution[pdgid] = (pt_resolution_abs, pt_resolution_rel)
self.eta_resolution[pdgid] = (eta_resolution_abs, eta_resolution_rel)
self.phi_resolution[pdgid] = (phi_resolution_abs, phi_resolution_rel)
[docs] def add_observable(self, name, definition, required=False, default=None):
"""
Adds an observable as a string that can be parsed by Python's `eval()` function.
Parameters
----------
name : str
Name of the observable. Since this name will be used in `eval()` calls for cuts, this should not contain
spaces or special characters.
definition : str
An expression that can be parsed by Python's `eval()` function. As objects, all particles can be
used: `e`, `mu`, `tau`, `j`, `a`, `l`, `v` provide lists of electrons, muons, taus, jets, photons, leptons (
electrons and muons combined), and neutrinos, in each case sorted by descending transverse momentum. `met` provides a
missing ET object. `p` gives all particles in the same order as in the LHE file (i.e. in the same order as
defined in the MadGraph process card). All these objects are instances of `MadMinerParticle`, which
inherits from scikit-hep's [LorentzVector](http://scikit-hep.org/api/math.html#vector-classes). See the link
for a documentation of their properties. In addition, `MadMinerParticle` have properties `charge` and
`pdg_id`, which return the charge in units of elementary charges (i.e. an electron has `e[0].charge = -1.`),
and the PDG particle ID. For instance, `"abs(j[0].phi() - j[1].phi())"` defines the azimuthal angle between
the two hardest jets.
required : bool, optional
Whether the observable is required. If True, an event will only be retained if this observable is
successfully parsed. For instance, any observable involving `"j[1]"` will only be parsed if there are at
least two jets passing the acceptance cuts. Default value: False.
default : float or None, optional
If `required=False`, this is the placeholder value for observables that cannot be parsed. None is replaced
with `np.nan`. Default value: None.
Returns
-------
None
"""
if required:
logger.debug("Adding required observable %s = %s", name, definition)
else:
logger.debug("Adding optional observable %s = %s with default %s", name, definition, default)
self.observables[name] = definition
self.observables_required[name] = required
self.observables_defaults[name] = default
[docs] def add_observable_from_function(self, name, fn, required=False, default=None):
"""
Adds an observable defined through a function.
Parameters
----------
name : str
Name of the observable. Since this name will be used in `eval()` calls for cuts, this should not contain
spaces or special characters.
fn : function
A function with signature `observable(particles)` where the input arguments are lists of
MadMinerParticle instances (ordered in the same way as in the LHE file) and a float is returned. The
function should raise a `RuntimeError` to signal that it is not defined.
required : bool, optional
Whether the observable is required. If True, an event will only be retained if this observable is
successfully parsed. For instance, any observable involving `"j[1]"` will only be parsed if there are at
least two jets passing the acceptance cuts. Default value: False.
default : float or None, optional
If `required=False`, this is the placeholder value for observables that cannot be parsed. None is replaced
with `np.nan`. Default value: None.
Returns
-------
None
"""
if required:
logger.debug("Adding required observable %s defined through external function", name)
else:
logger.debug(
"Adding optional observable %s defined through external function with default %s", name, default
)
self.observables[name] = fn
self.observables_required[name] = required
self.observables_defaults[name] = default
[docs] def add_default_observables(
self,
n_leptons_max=2,
n_photons_max=2,
n_jets_max=2,
include_met=True,
include_visible_sum=True,
include_numbers=True,
include_charge=True,
):
"""
Adds a set of simple standard observables: the four-momenta (parameterized as E, pT, eta, phi) of the hardest
visible particles, and the missing transverse energy.
Parameters
----------
n_leptons_max : int, optional
Number of hardest leptons for which the four-momenta are saved. Default value: 2.
n_photons_max : int, optional
Number of hardest photons for which the four-momenta are saved. Default value: 2.
n_jets_max : int, optional
Number of hardest jets for which the four-momenta are saved. Default value: 2.
include_met : bool, optional
Whether the missing energy observables are stored. Default value: True.
include_visible_sum : bool, optional
Whether observables characterizing the sum of all particles are stored. Default value: True.
include_numbers : bool, optional
Whether the number of leptons, photons, and jets is saved as observable. Default value: True.
include_charge : bool, optional
Whether the lepton charge is saved as observable. Default value: True.
Returns
-------
None
"""
logger.debug("Adding default observables")
# ETMiss
if include_met:
self.add_observable("et_miss", "met.pt", required=True)
self.add_observable("phi_miss", "met.phi()", required=True)
# Sum of visible particles
if include_visible_sum:
self.add_observable("e_visible", "visible.e", required=True)
self.add_observable("eta_visible", "visible.eta", required=True)
# Individual observed particles
for n, symbol, include_this_charge in zip(
[n_leptons_max, n_photons_max, n_jets_max], ["l", "a", "j"], [False, False, include_charge]
):
if include_numbers:
self.add_observable("n_{}s".format(symbol), "len({})".format(symbol), required=True)
for i in range(n):
self.add_observable(
"e_{}{}".format(symbol, i + 1), "{}[{}].e".format(symbol, i), required=False, default=0.0
)
self.add_observable(
"pt_{}{}".format(symbol, i + 1), "{}[{}].pt".format(symbol, i), required=False, default=0.0
)
self.add_observable(
"eta_{}{}".format(symbol, i + 1), "{}[{}].eta".format(symbol, i), required=False, default=0.0
)
self.add_observable(
"phi_{}{}".format(symbol, i + 1), "{}[{}].phi()".format(symbol, i), required=False, default=0.0
)
if include_this_charge and symbol == "l":
self.add_observable(
"charge_{}{}".format(symbol, i + 1),
"{}[{}].charge".format(symbol, i),
required=False,
default=0.0,
)
[docs] def add_cut(self, definition, pass_if_not_parsed=False):
"""
Adds a cut as a string that can be parsed by Python's `eval()` function and returns a bool.
Parameters
----------
definition : str
An expression that can be parsed by Python's `eval()` function and returns a bool: True for the event
to pass this cut, False for it to be rejected. In the definition, all visible particles can be
used: `e`, `mu`, `j`, `a`, and `l` provide lists of electrons, muons, jets, photons, and leptons (electrons
and muons combined), in each case sorted by descending transverse momentum. `met` provides a missing ET
object. `visible` and `all` provide access to the sum of all visible particles and the sum of all visible
particles plus MET, respectively. All these objects are instances of `MadMinerParticle`, which inherits from
scikit-hep's [LorentzVector](http://scikit-hep.org/api/math.html#vector-classes). See the link for a
documentation of their properties. In addition, `MadMinerParticle` have properties `charge` and `pdg_id`,
which return the charge in units of elementary charges (i.e. an electron has `e[0].charge = -1.`), and the
PDG particle ID. For instance, `"len(e) >= 2"` requires at least two electrons passing the cuts,
while `"mu[0].charge > 0."` specifies that the hardest muon is positively charged.
pass_if_not_parsed : bool, optional
Whether the cut is passed if the observable cannot be parsed. Default value: False.
Returns
-------
None
"""
logger.debug("Adding cut %s", definition)
self.cuts.append(definition)
self.cuts_default_pass.append(pass_if_not_parsed)
[docs] def reset_observables(self):
""" Resets all observables. """
logger.debug("Resetting observables")
self.observables = OrderedDict()
self.observables_required = OrderedDict()
self.observables_defaults = OrderedDict()
[docs] def reset_cuts(self):
""" Resets all cuts. """
logger.debug("Resetting cuts")
self.cuts = []
self.cuts_default_pass = []
[docs] def analyse_samples(self, reference_benchmark=None, parse_events_as_xml=True):
"""
Main function that parses the LHE samples, applies detector effects, checks cuts, and extracts
the observables and weights.
Parameters
----------
reference_benchmark : str or None, optional
The weights at the nuisance benchmarks will be rescaled to some reference theta benchmark:
`dsigma(x|theta_sampling(x),nu) -> dsigma(x|theta_ref,nu) = dsigma(x|theta_sampling(x),nu)
* dsigma(x|theta_ref,0) / dsigma(x|theta_sampling(x),0)`. This sets the name of the reference benchmark.
If None, the first one will be used. Default value: None.
parse_events_as_xml : bool, optional
Decides whether the LHE events are parsed with an XML parser (more robust, but slower) or a text parser
(less robust, faster). Default value: True.
Returns
-------
None
"""
# Input
if reference_benchmark is None:
reference_benchmark = self.benchmark_names_phys[0]
self.reference_benchmark = reference_benchmark
# Reset observations
self.observations = None
self.weights = None
self.nuisance_parameters = None
for lhe_file, is_background, sampling_benchmark, k_factor in zip(
self.lhe_sample_filenames, self.sample_is_backgrounds, self.sampling_benchmarks, self.sample_k_factors
):
logger.info("Analysing LHE sample %s", lhe_file)
# Read systematics setup from LHE file
logger.debug("Extracting nuisance parameter definitions from LHE file")
nuisance_parameters = extract_nuisance_parameters_from_lhe_file(lhe_file, self.systematics)
logger.debug("Found %s nuisance parameters with matching benchmarks:", len(nuisance_parameters))
for key, value in six.iteritems(nuisance_parameters):
logger.debug(" %s: %s", key, value)
# Compare to existing data
if self.nuisance_parameters is None:
self.nuisance_parameters = nuisance_parameters
else:
if dict(self.nuisance_parameters) != dict(nuisance_parameters):
raise RuntimeError(
"Different LHE files have different definitions of nuisance parameters / benchmarks!\nPrevious: {}\nNew:{}".format(
self.nuisance_parameters, nuisance_parameters
)
)
# Calculate observables and weights in LHE file
this_observations, this_weights = parse_lhe_file(
filename=lhe_file,
sampling_benchmark=sampling_benchmark,
benchmark_names=self.benchmark_names_phys,
is_background=is_background,
observables=self.observables,
observables_required=self.observables_required,
observables_defaults=self.observables_defaults,
cuts=self.cuts,
cuts_default_pass=self.cuts_default_pass,
energy_resolutions=self.energy_resolution,
pt_resolutions=self.pt_resolution,
eta_resolutions=self.eta_resolution,
phi_resolutions=self.phi_resolution,
k_factor=k_factor,
parse_events_as_xml=parse_events_as_xml,
)
# No events found?
if this_observations is None:
logger.debug("No observations in this LHE file, skipping it")
continue
logger.debug("Found weights %s in LHE file", list(this_weights.keys()))
# Check number of events in observables
n_events = None
for key, obs in six.iteritems(this_observations):
this_n_events = len(obs)
if n_events is None:
n_events = this_n_events
logger.debug("Found %s events", n_events)
if this_n_events != n_events:
raise RuntimeError(
"Mismatching number of events in LHE observations for {}: {} vs {}".format(
key, n_events, this_n_events
)
)
# Check number of events in weights
for key, weights in six.iteritems(this_weights):
this_n_events = len(weights)
if n_events is None:
n_events = this_n_events
logger.debug("Found %s events", n_events)
if this_n_events != n_events:
raise RuntimeError(
"Mismatching number of events in weights {}: {} vs {}".format(key, n_events, this_n_events)
)
# Rescale nuisance parameters to reference benchmark
reference_weights = this_weights[reference_benchmark]
sampling_weights = this_weights[sampling_benchmark]
for key in this_weights:
if key not in self.benchmark_names_phys: # Only rescale nuisance benchmarks
this_weights[key] = reference_weights / sampling_weights * this_weights[key]
# First results
if self.observations is None and self.weights is None:
self.observations = this_observations
self.weights = this_weights
continue
# Following results: check consistency with previous results
if len(self.weights) != len(this_weights):
raise ValueError(
"Number of weights in different files incompatible: {} vs {}".format(
len(self.weights), len(this_weights)
)
)
if len(self.observations) != len(this_observations):
raise ValueError(
"Number of observations in different Delphes files incompatible: {} vs {}".format(
len(self.observations), len(this_observations)
)
)
# Merge results with previous
for key in self.weights:
assert key in this_weights, "Weight label {} not found in sample!".format(key)
self.weights[key] = np.hstack([self.weights[key], this_weights[key]])
for key in self.observations:
assert key in this_observations, "Observable {} not found in Delphes sample!".format(key)
self.observations[key] = np.hstack([self.observations[key], this_observations[key]])
[docs] def save(self, filename_out):
"""
Saves the observable definitions, observable values, and event weights in a MadMiner file. The parameter,
benchmark, and morphing setup is copied from the file provided during initialization. Nuisance benchmarks found
in the LHE file are added.
Parameters
----------
filename_out : str
Path to where the results should be saved.
Returns
-------
None
"""
if self.observations is None or self.weights is None:
logger.warning("No observations to save!")
return
logger.debug("Loading HDF5 data from %s and saving file to %s", self.filename, filename_out)
# Save nuisance parameters and benchmarks
weight_names = list(self.weights.keys())
logger.debug("Weight names: %s", weight_names)
save_nuisance_setup_to_madminer_file(
filename_out,
weight_names,
self.nuisance_parameters,
reference_benchmark=self.reference_benchmark,
copy_from=self.filename,
)
# Save events
save_events_to_madminer_file(filename_out, self.observables, self.observations, self.weights)