Plotting format

A plotting file defines a set of options that are used for analysis and representation purposes, particularly to determine how datasets should be represented in plots and how they should be grouped together according to various criteria. The plotting files should be considered part of the implementation of the dataset, and should be read by various tools that want to sensibly represent the data.

Naming convention

Plotting files are located in the commondata folder (nnpdfcpp/data/commondata). For a dataset labeled <DATASET>, the corresponding file name is PLOTTING_<DATASET>.yaml or PLOTTING_<DATASET>.yml

For example, given the dataset “HERA1CCEP”, the corresponding plotting file name is:


Additionally, the configuration is loaded from a per-process-type file called:


See kinematic labels below for a list of defined types. When a key is present both in the dataset-specific and the per-process-type file, the dataset-specific one always takes precedence.


The plotting file specifies the variable in which the data is to be plotted (in the x axis) as well as the variables in which the data will be split in different lines in the same figure or in different figures. The possible variables (‘kinematic labels’) are described below.

The format also allows the control of several plotting properties, such as whether to use log scale, or the axes labels.

Data label

A key called dataset_label can be used to specify a nice plotting and display label for each dataset. LaTeX math is allowed between dollar signs. See the example plotting file for usage.

Kinematic labels

The default kinematic variables are inferred from the process type declared in the commondata files (more specifically from a substring). Currently they are:

'DIS': ('$x$', '$Q^2 (GeV^2)$', '$y$'),
'DYP': ('$y$', '$M^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWJ_JPT': ('$p_T (GeV)$', '$M^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWJ_JRAP': ('$\\eta/y$', '$M^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWJ_MLL': ('$M_{ll} (GeV)$', '$M_{ll}^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWJ_PT': ('$p_T (GeV)$', '$M^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWJ_PTRAP': ('$\\eta/y$', '$p_T^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWJ_RAP': ('$\\eta/y$', '$M^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWK_MLL': ('$M_{ll} (GeV)$', '$M_{ll}^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWK_PT': ('$p_T$ (GeV)', '$M^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWK_PTRAP': ('$\\eta/y$', '$p_T^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'EWK_RAP': ('$\\eta/y$', '$M^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'HIG_RAP': ('$y$', '$M_H^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'HQP_MQQ': ('$M^{QQ} (GeV)$', '$\\mu^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'HQP_PTQ': ('$p_T^Q (GeV)$', '$\\mu^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'HQP_PTQQ': ('$p_T^{QQ} (GeV)$', '$\\mu^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'HQP_YQ': ('$y^Q$', '$\\mu^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'HQP_YQQ': ('$y^{QQ} (GeV)$', '$\\mu^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'INC': ('$0$', '$\\mu^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'JET': ('$\\eta$', '$p_T^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'PHT': ('$\\eta_\\gamma$', '$E_{T,\\gamma}^2 (GeV^2)$', '$\\sqrt{s} (GeV)$'),
'SIA': ('$z$', '$Q^2 (GeV^2)$', '$y$')

This mapping is declared as CommonData.kinLabel_latex in the C++ code (and accessible as validphys.plotoptions.core.kinlabels_latex in the Python code).

The three kinematic variables are referred to as k1, k2 and k3 in the plotting files. For example, for DIS processes, k1 refers to x, k2 to Q, and k3 to y.

These kinematic values can be overridden by some transformation of them. For that purpose, it is possible to define a kinematics_override key. The value must be a class defined in: validphys2/src/validphys/plotoptions/

The class must have a __call__ method that takes three parameters: (k1, k2 k3) as defined in the dataset implementation, and returns three new values ('k1', 'k2', k3') which are the “transformed” kinematical variables, which will be used for plotting purposes every time the kinematic variables k1, k2 and k3 are referred to. Additionally, the class must implement a new_labels method, that takes the old labels and returns the new ones, and an xq2map function that takes the kinematic variables and returns a tuple of (x, Q²) with some approximate values. An example of such transform is:

class dis_sqrt_scale:
    def __call__(self, k1, k2, k3):
        ecm = sqrt(k2/(k1*k3))
        return k1, sqrt(k2), ceil(ecm)

    def new_labels(self, *old_labels):
        return ('$x$', '$Q$ (GeV)', r'$\sqrt{s} (GeV)$')

    def xq2map(self, k1, k2, k3, **extra_labels):
        return k1, k2*k2

Additional labels can be specified by declaring an extra_labels key in the plotting file, and specifying for each new label a value for each point in the dataset.

For example:

    idat2bin:  [0, 0, 0, 0, 0, 0, 0, 0, 100, 100, 100, 100, 100, 200, 200, 200, 300, 300, 300, 400, 400, 400, 500, 500, 600, 600, 700, 700, 800, 800, 900, 1000, 1000, 1100]

defines one label where the values for each of the datapoints are given in the list. Note that the name of the extra_label (in this case idat2bin is completely arbitrary, and will be used for plotting purposes (LaTeX math syntax is allowed as well). However, adding labels manually for each point can be tedious. This should only be reserved for information that cannot be recovered from the kinematics as defined in the CommonData file. Instead, new labels can be generated programmatically: every function defined in validphys2/src/validphys/plotoptions/ is a valid label. These functions take as keyword arguments the (possibly transformed) kinematical variables, as well as any extra label declared in the plotting file. For example, one might declare:

def high_xq(k1, k2, k3, **kwargs):
    return k1 > 1e-2 and k2 > 1000

Note that it is convenient to always declare the **kwargs parameter so that the code doesn’t crash when the function is called with extra arguments. Similarly to the kinematics transforms, it is possible to decorate them with a @label describing a nicer latex label than the function name. For example:

@label(r"$I(x>10^{-2})\times I(Q > 1000 GeV)$")
def high_xq(k1, k2, k3, **kwargs):
    return (k1 > 1e-2) & (k2 > 1000)

Plotting and grouping

The variable in which the data is plotted is simply declared as

x: <label>

For example:

x: k1

If a line_by key is specified, variables with different values for each of the labels listed, will be represented as different lines. For example,

  - k2

for DIS would mean that the data in the same Q bin is plotted in the same line.

Similarly, it is possible to define a figure_by key: Points with different values for the listed keys will be split across separated figures. For example:

  - idat2bin
  - high_xq

Transforming the result

By default the y axis represents the central value and error. However, it is possible to define a results_transform in the plotting file:

result_transform: qbinexp

The value must be a function declared in validphys2/src/validphys/plotoptions/ taking the error, the central value, as well as all the labels, and returning a new error and central value. For example:

def qbinexp(cv, error, **labels):
    q = labels['k2']
    qbin = bins(q)
    return 10**qbin*cv, 10**qbin*error

Plotting options

Several plotting options can be specified. These include

  • x/y_scale: ‘linear’ or ‘log’.

  • x/y_label: Any string, possibly latex formatted. Note that the x_label will be deduced automatically.

Overriding configuration for normalized plots

When the results are to be plotted as a ratio, it may be convenient to alter the configuration of the plots, for example by changing the line_by labels into figure_by (because otherwise the points would overlap), or by changing the scale from log to linear. To do so, we specify the options we want to override in a normalize key. Everything defined inside will take precedence when we produce a ratio plot and will be ignored for absolute value plots. For example:

x: k1

x_label: '$\left\|\eta/y\right|$'

y_label: '$d\sigma/dy$ (fb)'

  - Boson

        - Boson

   Boson:  ["$W^+$","$W^+$","$W^+$","$W^+$","$W^+$","$W^+$","$W^+$","$W^+$","$W^+$","$W^+$","$W^+$","$W^-$","$W^-$","$W^-$","$W^-$","$W^-$","$W^-$","$W^-$","$W^-$","$W^-$","$W^-$","$W^-$","$Z$","$Z$","$Z$","$Z$","$Z$","$Z$","$Z$","$Z$"]

Here, we would split the data by different figure files for each unique value of the key Boson (which is defined explicitly as an extra_label), but only one plot with the three bosons split across different lines will be produced in absolute value plots.

Metadata keys

Plotting files are also used to define metadata related to the various datasets. These keys include:

  • experiment (string): The experiment which produced the experimental data.

  • process_description (string): A description of the physical process associated to the dataset. This would typically be defined in the PLOTTINGTYPE files.

  • data_reference (string): a LaTeX key corresponding to the reference of the experimental paper.

  • theory_reference (string): a LaTeX key corresponding to the codes used to compute the theory predictions.


A complete example (all keys are optional) looks like this:

dataset_label: "Some hypothetical dataset"
experiment: ATLAS
x: k3
x_scale: log
kinematics_override: dummy_transform #defined in
  - k2

  - idat2bin #defined below
  - high_xq  #defined in

normalize: # Change the scale for ratio plots
    x_scale: linear

    idat2bin:  [0, 0, 0, 0, 0, 0, 0, 0, 100, 100, 100, 100, 100, 200, 200, 200, 300, 300, 300, 400, 400, 400, 500, 500, 600, 600, 700, 700, 800, 800, 900, 1000, 1000, 1100]