hist2workspace (1)

hist2workspace [option] input.xml

hist2workspace is a utility to create RooFit/RooStats workspace from histograms

-standard_form default model, which creates an extended PDF that interpolates between RooHistFuncs. This is much faster for models with many bins and uses significantly less memory.

-number_counting_form this was the original model in 5.28 (without patches). It uses a Poisson for each bin of the histogram. This can become slow and memory intensive when there are many bins.

The ROOT release ships with a script prepareHistFactory in the $ROOTSYS/bin directory that prepares a working area. It creates a results/, data/, and config/ directory. It also copies the HistFactorySchema.dtd and example XML files into the config/ directory. Additionally, it copies a root file into the data/ directory for use with the examples.

This file is located in $ROOTSYS/etc/ specifies the XML schema. It is typically placed in the config/ directory of a working area together with the top-level XML file and the individual channel XML files. The user should not modify this file.

The HistFactorySchema.dtd is commented to specify exactly the meaning of the various options.

(see for example $ROOTSYS/tutorials/histfactory/example.xml) This file is edited by the user. It specifies - A top level 'Combination' that is composed of:

    - several 'Channels', which are described in separate XML files.
    - several 'Measurements' (corresponding to a full fit of the model) each of which specifies
      - a name for this measurement to be used in tables and files
      - what is the luminosity associated to the measurement in picobarns
      - which bins of the histogram should be used
      - what is the relative uncertainty on the luminosity
      - what is (are) the parameter(s) of interest that will be measured
      - which parameters should be fixed/floating (eg. nuisance parameters)
      - which type of constriants are desired

- Gaussian by default - Gamma, LogNormal, and Uniform are also supported

      - if the tool should export the model only and skip the default fit

(see for example $ROOTSYS/tutorials/histfactory/example_channel.xml) This file is edited by the user. It specifies for each channel - observed data

   - if absent the tool will use the expectation, which is useful for expected sensitivity

- several 'Samples' (eg. signal, bkg1, bkg2, ...), each of which has:

   - a name
   - if the sample is normalized by theory (eg N = L*sigma) or not (eg. data driven)
   - a nominal expectation histogram
   - a named 'Normalization Factor' (which can be fixed or allowed to float in a fit)
   - several 'Overall Systematics' in normalization with:
     - a name
     - +/- 1 sigma variations (eg. 1.05 and 0.95 for a 5% uncertainty)
   - several 'Histogram Systematics' in shape with:
     - a name (which can be shared with the OverallSyst if correlated)
     - +/- 1 sigma variational histograms

Kyle Cranmer , Akira Shibata , and Dominique Tardif

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA