NAME

       hist2workspace - utility to create RooFit/RooStats workspace from histograms

SYNOPSIS

       hist2workspace [option] input.xml

DESCRIPTION

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

OPTIONS

       -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.

Prepare working area

       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.

HistFactorySchema.dtd

       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.

Top-Level XML File

       (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

Channel XML Files

       (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

ORIGINAL AUTHORS

              Kyle Cranmer , Akira Shibata , and Dominique Tardif

COPYRIGHT

       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

                                            DEC. 2010                          HISTTOWORKSPACE(1)