Add Hybrid class with methods to calculate the hybrid weights from a given MC...

Add Hybrid class with methods to calculate the hybrid weights from a given MC sample and to get the weight for a given phase space point.

eFFORT/hybrid/hybrid_binning.json

+{
+  "BINS_MX": [0.0, 1.4, 1.6, 1.8, 2.0, 2.5, 3.0, 3.5],
+  "BINS_ELB":[0.0, 0.5, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 3.0],
+  "BINS_Q2": [0.0, 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 20.0, 25.0]
+}
\ No newline at end of file

eFFORT/hybrid/hybrid_model.py

+import numpy
+import pandas
+import json
+import os
+from pathlib import Path
+
+BINS_MX = numpy.array([0., 1.4, 1.6, 1.8, 2., 2.5, 3., 3.5])
+BINS_ELB = numpy.array([0., 0.5, 1., 1.25, 1.5, 1.75, 2., 2.25, 3.])
+BINS_Q2 = numpy.array([0., 2.5, 5., 7.5, 10., 12.5, 15., 20., 25.])
+
+
+class Hybrid:
+
+    def __init__(self, hybrid_config: str = None) -> None:
+        """Initialize the hybrid weight with the given configuration.
+
+        The default binning is given by
+        * BINS_MX: [0.0, 1.4, 1.6, 1.8, 2.0, 2.5, 3.0, 3.5]
+        * BINS_EL":[0.0, 0.5, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 3.0]
+        * BINS_Q": [0.0, 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 20.0, 25.0]
+        which is motivated by theory. This should only be changed with proper theoretical motivation.
+
+        Parameters
+        ----------
+        hybrid_config: str
+            Path to json file defining the binning of the Hybrid model. Has to contain the three attributes:
+            * BINS_MX: The binning for the Hybrid model in mX.
+            * BINS_ELB: The binning of the Hybrid model in El_B.
+            * BINS_Q2: The binning of the Hybrid model in q2.
+        """
+
+        if hybrid_config is None:
+            this_dir = Path(__file__).parent
+            hybrid_config = this_dir / 'hybrid_binning.json'
+
+        with open(hybrid_config) as json_file:
+            config = json.load(json_file)
+
+        self.bins_mX = config['BINS_MX']
+        self.bins_El_B = config['BINS_ELB']
+        self.bins_q2 = config['BINS_Q2']
+
+        self.range_mX = (self.bins_mX[0], self.bins_mX[1])
+        self.range_El_B = (self.bins_El_B[0], self.bins_El_B[1])
+        self.range_q2 = (self.bins_q2[0], self.bins_q2[1])
+
+    def calculate_weight(self, x: numpy.array, hybrid_weights: numpy.array) -> float:
+        """Calculate the weight in the 3D phase space of the inclusive model.
+
+        Parameters
+        ----------
+        x : numpy.array
+            Phase space location of the inclusive prediction in the form (El_B, q2, mX).
+        hybrid_weights: numpy:array
+            Hybrid weights generated by :func:`~hybrid.Hybrid.generate_hybrid_weights`.
+
+        Returns
+        -------
+        hybrid_weight: float
+            The hybrid weight w_i at the given phase space point x.
+        """
+        try:
+            return hybrid_weights[
+                int(numpy.digitize(x[0], self.bins_El_B)) - 1,
+                int(numpy.digitize(x[1], self.bins_q2)) - 1,
+                int(numpy.digitize(x[2], self.bins_mX)) - 1
+            ]
+        except IndexError:
+            return 0
+
+    def generate_hybrid_weights(self, inclusive: pandas.DataFrame, exclusive: pandas.DataFrame) -> numpy.array:
+        """Calculate the Hybrid weights w_i, so that the bin content in the Hybrid model is given by
+        H_i = R_i + w_i I_i, where H_i is the bin content of the inclusive prediction in the Hybrid model, R_i is the bin
+        content of the resonant contributions, and I_i is the bin content of the total inclusive prediction.
+
+        The required columns in the inclusive and exclusive data frames are:
+        * mX: the invariant mass of the hadronic system (the mass of the resonance).
+        * El_B: the lepton momentum in the B reference frame.
+        * q2: the momentum transfer to the lepton-neutrino system.
+
+        Parameters
+        ----------
+        inclusive: pandas.DataFrame
+            Inclusive MC.
+        exclusive: pandas.DataFrame
+            Exclusive MC. Can contain any number of resonances.
+
+        Returns
+        -------
+        hybrid_weights: numpy.array
+            3D histogram containing the weights of the Hybrid model. To be used with
+            :func:`~hybrid.Hybrid.calculate_weight`.
+        """
+        H_exc, _ = numpy.histogramdd(
+            exclusive[['El_B', 'q2', 'mX']].values,
+            bins=[self.bins_El_B, self.bins_q2, self.bins_mX],
+            range=[self.range_El_B, self.range_q2, self.range_mX],
+            normed=False,
+            weights=exclusive['__weight__']
+        )
+
+        H_incl, _ = numpy.histogramdd(
+            inclusive[['El_B', 'q2', 'mX']].values,
+            bins=[self.bins_El_B, self.bins_q2, self.bins_mX],
+            range=[self.range_El_B, self.range_q2, self.range_mX],
+            normed=False,
+            weights=inclusive['__weight__']
+        )
+
+        hybrid_weights = (H_incl - H_exc) / H_incl
+
+        # Replace nan values with 1
+        hybrid_weights = numpy.where(
+            numpy.isnan(hybrid_weights), numpy.ones(hybrid_weights.shape), hybrid_weights)
+        # Replace < 0 values with 0
+        hybrid_weights = numpy.where(
+            hybrid_weights < 0, numpy.zeros(hybrid_weights.shape), hybrid_weights)
+
+        return hybrid_weights