### Check Git Version

Source: https://github.com/trexstats/trexfitter/blob/master/CONTRIBUTING.md

Verify the installed Git version on the system. This is a basic setup step.

```bash
git --version
```

--------------------------------

### Setup TRExFitter Environment

Source: https://github.com/trexstats/trexfitter/blob/master/README.md

Use these commands to set up the StatAnalysis environment, which includes TRExFitter. Ensure you have the correct version of StatAnalysis installed.

```bash
setupATLAS
asetup StatAnalysis,0.7.3
```

--------------------------------

### Configure EFT Setup

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define EFT parameters, including ranges for Wilson coefficients, EFT order, and binning strategy.

```plaintext
EFTConfig: "eft_setup"
  ParameterMinMax: cHt,-10,10:cHQ1,-5,5
  EFTOrder: ALL
  SplitSamplePerBin: TRUE
```

--------------------------------

### Set Output Directories

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Specifies the output directories for runtime artifacts, libraries, and installable libraries. This helps organize build outputs.

```cmake
set( CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin )
set( CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib )
set( CMAKE_INSTALL_LIBDIR ${CMAKE_BINARY_DIR}/lib )
```

--------------------------------

### Commit changes and push to GitLab

Source: https://github.com/trexstats/trexfitter/blob/master/CONTRIBUTING.md

Follow these steps to commit local changes and push them to your GitLab repository. Ensure you are on a clean, up-to-date branch before starting.

```bash
cd TRExFitter
git status # start from a clean state, up-to-date with the origin
git remote add upstream ssh://git@gitlab.cern.ch:7999/TRExStats/TRExFitter.git # sets upstream to the main repository, you only need to do this once
git fech upstream # downloads the changes from upstream repository
git rebase upstream/master # rebase on top of the upstream/master branch
git checkout -b some-project  # put your work on a branch
git diff <file> # look at the diff between current HEAD and local version to see what you will add
git add <list of files> # add files you want to change
git commit -m "your commit message" some.txt file.txt  # commit files and prompt editor for commit message
git push -u origin some-project  # push your changes to gitlab, parameter -u sets upstream
git checkout master  # to go back to the origin, to be able to synchronise with it again
```

--------------------------------

### Configure Morphing Parameter

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define the morphing parameter itself, including its fit function, starting value, and limits.

```plaintext
Morphing: "mass_morph"
  FitFunction: QUADRATIC
  ParamStartValue: 750
  ParamLimits: 500,1000
```

--------------------------------

### TRExFitter Citation Example

Source: https://github.com/trexstats/trexfitter/blob/master/README.md

BibTeX entry for citing TRExFitter in publications. Includes author, title, publisher, DOI, and URL.

```bibtex
@software{TRExFitter,
  author       = {{ATLAS Collaboration}},
  title        = {TRExFitter},
  publisher    = {Zenodo},
  doi          = {10.5281/zenodo.14845712},
  url          = {https://doi.org/10.5281/zenodo.14845712},
}
```

--------------------------------

### Configure Asymptotic and Toy-Based Upper Limits

Source: https://context7.com/trexstats/trexfitter/llms.txt

Use ASYMPTOTIC for quick estimates or TOYS for more robust, toy-based limits. Ensure POI is correctly specified.

```plaintext
Limit: "limit"
  LimitType: ASYMPTOTIC
  LimitBlind: TRUE
  POI: mu_signal
  ConfidenceLevel: 0.95
  SignalInjection: FALSE
```

```plaintext
Limit: "limit_toys"
  LimitType: TOYS
  LimitBlind: FALSE
  POI: mu_signal
  SplusBToys: 10000
  BonlyToys: 10000
  ScanSteps: 20
  ScanMin: 0
  ScanMax: 5
  ToysSeed: 12345
```

--------------------------------

### Find and Include xRooFit

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Attempts to find the xRooFit package. If not found, it includes the local xroofit directory as a subdirectory.

```cmake
if( NOT USE_LOCAL_XROOFIT )
  find_package( xRooFit QUIET )
endif()
if( NOT xRooFit_FOUND )
  include_directories( xroofit )
  add_subdirectory( xroofit )
endif()
```

--------------------------------

### Configure Individual Fit Configurations for Combination

Source: https://context7.com/trexstats/trexfitter/llms.txt

Specify configuration files for individual channels that will be combined.

```plaintext
Fit: "channel1"
  ConfigFile: config/channel1.config
  Label: "Channel 1"
```

```plaintext
Fit: "channel2"
  ConfigFile: config/channel2.config
  Label: "Channel 2"
```

--------------------------------

### Run TRExFitter Command Line Steps

Source: https://context7.com/trexstats/trexfitter/llms.txt

Execute various TRExFitter analysis steps using the `trex-fitter` command-line tool. Each command corresponds to a specific stage of the analysis workflow.

```bash
trex-fitter h config/myFit.config
```

```bash
trex-fitter n config/myFit.config
```

```bash
trex-fitter w config/myFit.config
```

```bash
trex-fitter f config/myFit.config
```

```bash
trex-fitter dp config/myFit.config
```

```bash
trex-fitter x config/myFit.config
```

```bash
trex-fitter r config/myFit.config
```

```bash
trex-fitter l config/myFit.config
```

```bash
trex-fitter s config/myFit.config
```

```bash
trex-fitter hwf config/myFit.config
```

```bash
trex-fitter mwf config/myMultiFit.config
```

```bash
trex-fitter hwf config/myFit.config "Regions=SR1,SR2:Samples=ttbar,signal"
```

--------------------------------

### Configure Asymptotic and Toy-Based Significance

Source: https://context7.com/trexstats/trexfitter/llms.txt

Set up significance calculations using ASYMPTOTIC for speed or TOYS for toy-based results. POIAsimov is relevant for asymptotic calculations.

```plaintext
Significance: "significance"
  SignificanceType: ASYMPTOTIC
  SignificanceBlind: FALSE
  POI: mu_signal
  POIAsimov: 1
```

```plaintext
Significance: "significance_toys"
  SignificanceType: TOYS
  SplusBToys: 10000
  BonlyToys: 10000
  ToysSeed: 12345
```

--------------------------------

### Configure xRooFit Usage

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Controls whether to use a local xRooFit submodule or a system-installed version. Defaults to using a local submodule if not explicitly set.

```cmake
set(USE_LOCAL_XROOFIT TRUE CACHE BOOL "If true will use xroofit submodule")
```

--------------------------------

### TRExFitter Configuration - Sample Block (Background)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a background sample. Specify type, title, fill color, line color, and histogram file.

```config
Sample: "ttbar"
  Type: BACKGROUND
  Title: "t#bar{t}"
  FillColor: 0
  LineColor: 1
  HistoFile: "ttbar"
```

--------------------------------

### Configure SM Reference Sample for EFT

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define the Standard Model reference sample for EFT calculations, specifying its title and histogram file.

```plaintext
Sample: "SM_reference"
  Type: BACKGROUND
  Title: "SM"
  HistoFile: "sm_prediction"
```

--------------------------------

### Configure EFT Analysis Job

Source: https://context7.com/trexstats/trexfitter/llms.txt

Set up the main job configuration for an Effective Field Theory analysis.

```plaintext
Job: "EFTAnalysis"
  FitType: EFT
```

--------------------------------

### Configure Comparison Fit

Source: https://context7.com/trexstats/trexfitter/llms.txt

Set up a multi-fit configuration for comparing results, enabling comparison of POIs and pulls.

```plaintext
MultiFit: "Comparison"
  Combine: FALSE
  Compare: TRUE
  ComparePOI: TRUE
  ComparePulls: TRUE
  POI: mu_signal
```

--------------------------------

### Project Name and Version

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Defines the project name. This is used for identification within CMake.

```cmake
project( TRExFitter )
```

--------------------------------

### Configure C++ Standard

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Sets the required and target C++ standards for the build. C++17 is set as the standard, with C++11 as the minimum requirement. Compiler extensions are disabled.

```cmake
set( CMAKE_CXX_STANDARD_REQUIRED 11 CACHE STRING
   "Minimum C++ standard required for the build" )
set( CMAKE_CXX_STANDARD 17 CACHE STRING
   "C++ standard to use for the build" )
set( CMAKE_CXX_EXTENSIONS FALSE CACHE BOOL
   "(Dis)allow using compiler extensions" )
```

--------------------------------

### Configure Git User Information

Source: https://github.com/trexstats/trexfitter/blob/master/CONTRIBUTING.md

Set the global Git configuration for username and email. This is essential for identifying commits. Also configures UI and editor preferences.

```bash
git config --global user.name "First Last"
git config --global user.email "first.last@cern.ch"
git config --global color.ui auto
git config --global core.editor "emacs -nw"
```

--------------------------------

### TRExFitter Ntuple Configuration - Sample Block

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a signal sample for ntuple-based analysis. Specify type, title, ntuple file name, and MC weight.

```config
Sample: "ttH"
  Type: SIGNAL
  Title: "ttH"
  NtupleFile: "ttH_nominal"
  MCweight: "weight_ttH"
```

--------------------------------

### Build TRExUtils Library

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Defines and builds the TRExUtils library, which contains auxiliary classes for TRExFitter styling. It explicitly lists header and source files and links against ROOT libraries.

```cmake
set( _trex_utils_headers StyleUtils/TRExLabels.h StyleUtils/TRExStyle.h StyleUtils/TRExUtils.h )
set( _trex_utils_sources StyleUtils/TRExLabels.C StyleUtils/TRExStyle.C StyleUtils/TRExUtils.C )
add_library( TRExUtils SHARED ${_trex_utils_headers} ${_trex_utils_sources} )
target_include_directories( TRExUtils
   PUBLIC ${ROOT_INCLUDE_DIRS}
   $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}> $<INSTALL_INTERFACE:> )
target_link_libraries( TRExUtils ${ROOT_LIBRARIES} )
```

--------------------------------

### TRExFitter Configuration - Sample Block (Data)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines the data sample. Specify type, title, and the histogram file.

```config
Sample: "Data"
  Type: DATA
  Title: "Data"
  HistoFile: "data"
```

--------------------------------

### Build SystematicSmoothingTool Library

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Defines and builds the SystematicSmoothingTool library. It bypasses the library's own CMakeLists.txt to avoid external dependencies and explicitly lists sources and includes.

```cmake
set( _syst_smoothing_tool_sources
  SystematicSmoothingTool/Root/PlotHist.cxx
  SystematicSmoothingTool/Root/SmoothHist.cxx
  SystematicSmoothingTool/Root/SmoothingTool.cxx
  SystematicSmoothingTool/Root/TRExTools.cxx
)
add_library( SystematicSmoothingTool SHARED ${_syst_smoothing_tool_sources} )
target_include_directories( SystematicSmoothingTool
   PUBLIC ${ROOT_INCLUDE_DIRS}
   $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}> $<INSTALL_INTERFACE:> )
target_link_libraries( SystematicSmoothingTool ${ROOT_LIBRARIES} )
```

--------------------------------

### Find AnalysisBase

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Attempts to find the AnalysisBase package. This is an optional dependency.

```cmake
find_package( AnalysisBase QUIET)
```

--------------------------------

### Include and Add yaml-cpp Subdirectory

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Includes the yaml-cpp library's include directories and adds it as a subdirectory if AnalysisBase is not found. This ensures yaml-cpp is available for the build.

```cmake
include_directories( yaml-cpp )
if(NOT ${AnalysisBase_FOUND})
  add_subdirectory( yaml-cpp )
endif()
```

--------------------------------

### TRExFitter Configuration - Sample Block (Signal)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines the signal sample. Specify type, title, fill color, line color, and histogram file.

```config
Sample: "Signal"
  Type: SIGNAL
  Title: "Signal"
  FillColor: 632
  LineColor: 632
  HistoFile: "signal"
```

--------------------------------

### Configure Unfolding Sample

Source: https://context7.com/trexstats/trexfitter/llms.txt

Specify details for a particular sample used in unfolding, including its response matrix file and associated regions.

```plaintext
UnfoldingSample: "ttbar_unfold"
  Title: "t#bar{t}"
  ResponseMatrixFile: "response_ttbar"
  ResponseMatrixName: "h_response_ttbar"
  Regions: SR_unfold
```

--------------------------------

### Enable Compile Commands Export

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Enables the generation of a compile_commands.json file, useful for IDE integration and code analysis tools.

```cmake
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
```

--------------------------------

### Configure Template Morphing Job

Source: https://context7.com/trexstats/trexfitter/llms.txt

Set up the job for template morphing, enabling smoothing of morphed templates.

```plaintext
Job: "MorphingAnalysis"
  SmoothMorphingTemplates: TRUE
```

--------------------------------

### Configure Signal Sample for Morphing

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define signal samples for morphing, specifying their type, title, and the parameter and value for morphing.

```plaintext
Sample: "signal_m500"
  Type: SIGNAL
  Title: "Signal (m=500)"
  Morphing: "mass",500
```

```plaintext
Sample: "signal_m750"
  Type: SIGNAL
  Title: "Signal (m=750)"
  Morphing: "mass",750
```

```plaintext
Sample: "signal_m1000"
  Type: SIGNAL
  Title: "Signal (m=1000)"
  Morphing: "mass",1000
```

--------------------------------

### Configure Unfolding Analysis Job

Source: https://context7.com/trexstats/trexfitter/llms.txt

Set up the main job configuration for unfolding, specifying paths and names for the response matrix.

```plaintext
Job: "UnfoldingAnalysis"
  FitType: UNFOLDING
  ResponseMatrixPath: "matrices/"
  ResponseMatrixFile: "response"
  ResponseMatrixName: "h_response"
```

--------------------------------

### Configure Combined Fit

Source: https://context7.com/trexstats/trexfitter/llms.txt

Set up a combined fit across multiple channels. Specify labels, POI, and whether to combine or compare results.

```plaintext
MultiFit: "Combination"
  Label: "Combined Fit"
  Combine: TRUE
  Compare: FALSE
  POI: mu_signal
  CmeLabel: "13 TeV"
  LumiLabel: "140 fb^{-1}"
```

--------------------------------

### TRExFitter Ntuple Configuration - Job Block

Source: https://context7.com/trexstats/trexfitter/llms.txt

Configures a TRExFitter job to read directly from ROOT ntuples. Specify ntuple paths, weights, selections, and luminosity.

```config
Job: "NtupleAnalysis"
  ReadFrom: NTUP
  NtuplePaths: "/data/ntuples/"
  NtupleName: "nominal"
  MCweight: "weight*sf_btag*sf_lepton"
  Selection: "nJets>=4 && nBtags>=2"
  Lumi: 140000
```

--------------------------------

### Find ROOT

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Finds the ROOT data analysis framework, requiring specific components. This is a critical dependency for the project.

```cmake
find_package( ROOT 6.24.00 REQUIRED COMPONENTS Core MathCore HistFactory Graf Rio Tree Gpad )
```

--------------------------------

### Add Blinder Subdirectory

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Includes the Blinder directory as a subdirectory, allowing its CMakeLists.txt to be processed and its targets to be built.

```cmake
include_directories( Blinder )
add_subdirectory( Blinder )
```

--------------------------------

### Enable CTest

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Includes the CTest module to enable testing capabilities within the project.

```cmake
include( CTest )
```

--------------------------------

### Configure yaml-cpp Build

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Sets build options for the yaml-cpp library, disabling tests and tools. This is typically done when yaml-cpp is included as a subdirectory.

```cmake
set( YAML_CPP_BUILD_TESTS OFF )
set( YAML_CPP_BUILD_TOOLS OFF )
```

--------------------------------

### Configure EFT Interference Sample

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define an EFT sample representing interference terms, linking it to the SM reference and specifying the EFT parameter and value.

```plaintext
Sample: "EFT_cHt"
  Type: EFT
  Title: "cHt interference"
  EFTSMReference: SM_reference
  EFTParam: cHt
  EFTValue: 1.0
  HistoFile: "eft_cHt"
```

--------------------------------

### Configure EFT Squared Term Sample

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define an EFT sample representing squared terms of an EFT parameter, linking it to the SM reference.

```plaintext
Sample: "EFT_cHt_sq"
  Type: EFT
  Title: "cHt^2"
  EFTSMReference: SM_reference
  EFTParam: cHt
  EFTValue: 1.0
  HistoFile: "eft_cHt_squared"
```

--------------------------------

### Create a merge request

Source: https://github.com/trexstats/trexfitter/blob/master/CONTRIBUTING.md

After pushing your branch to your fork (origin), you can create a merge request to integrate your changes into the upstream repository. Click the 'Create merge request' button and provide a description.

```bash
git pull # is combination of git fetch and git merge, example: git pull upstream master
git checkout -- <files> # remove local changes on files in <files>
git merge <branch> # merges <branch> into your current branch
git branch -a # prints all local and remote branches
git branch -D <branch> # delete local branch <branch>
```

--------------------------------

### Configure Plotting Options in TRExFitter

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define image formats, ratio plot settings, and legend appearance. Use these options to customize the output of your analysis plots.

```yaml
Job: "MyAnalysis"
  ImageFormat: "png,pdf,eps"
  RatioYmin: 0.5
  RatioYmax: 1.5
  RatioYtitle: "Data/Pred."
  RatioType: DATAOVERMC
  SummaryPlotYmax: 1.5
  SummaryLogY: FALSE
  DoSummaryPlot: TRUE
  DoMergedPlot: TRUE
  DoTables: TRUE
  DoPieChartPlot: TRUE
  DoSignalRegionsPlot: TRUE
  PlotOptions: "NOXERR,CHI2"
  LabelX: 0.2
  LabelY: 0.87
  LegendX1: 0.6
  LegendX2: 0.9
  LegendY: 0.7
  LegendNColumns: 2

Region: "SR"
  LogScale: TRUE
  Ymin: 0.1
  Ymax: 10000
  RatioYmin: 0.7
  RatioYmax: 1.3
```

--------------------------------

### Configure 1D and 2D Likelihood Scans

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define parameters for 1D and 2D likelihood scans. Specify the parameter to scan, range, and number of steps.

```plaintext
Fit: "myfit"
  FitType: SPLUSB
  doLHscan: mu_signal
  LHscanMin: 0
  LHscanMax: 3
  LHscanSteps: 30
```

```plaintext
Fit: "fit_2d"
  FitType: SPLUSB
  do2DLHscan: mu_signal,mu_ttbar
  LHscanMin: 0
  LHscanMax: 3
  LHscanSteps: 20
  LHscanMinY: 0.5
  LHscanMaxY: 1.5
  LHscanStepsY: 20
```

--------------------------------

### Combine Multiple Systematic Sources

Source: https://context7.com/trexstats/trexfitter/llms.txt

Configure how multiple systematic sources, like PDF variations, are combined. ENVELOPE is a common combination type.

```plaintext
Systematic: "PDF_set"
  Title: "PDF"
  Type: HISTO
  Samples: all
  CombineName: "PDF_combined"
  CombineType: ENVELOPE
  HistoNameSufUp: "_PDF_0_up"
  HistoNameSufDown: "_PDF_0_down"
```

```plaintext
Systematic: "PDF_alpha"
  Title: "PDF alpha_s"
  Type: HISTO
  Samples: all
  CombineName: "PDF_combined"
  CombineType: ENVELOPE
  HistoNameSufUp: "_PDF_alpha_up"
  HistoNameSufDown: "_PDF_alpha_down"
```

--------------------------------

### TRExFitter Ntuple Configuration - Region Block

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines an analysis region for ntuple-based analysis. Specify variable, binning, selection criteria, label, and ntuple path suffix.

```config
Region: "SR_4j2b"
  Type: SIGNAL
  Variable: "mbb/1e3",20,0,500
  VariableTitle: "m_{bb} [GeV]"
  Selection: "nJets==4 && nBtags==2"
  Label: "4j, 2b"
  NtuplePathSuff: "4j2b"
```

--------------------------------

### Configure AVX Optimisation

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Enables or disables AVX (Advanced Vector Extensions) optimizations for the build. Defaults to enabled.

```cmake
set(TREXFITTER_AVX_OPTIMISATION TRUE CACHE BOOL "If true use AVX optimisation")
```

--------------------------------

### Clone TRExFitter Repository

Source: https://github.com/trexstats/trexfitter/blob/master/CONTRIBUTING.md

Clone the TRExFitter repository from the GitLab server using SSH. This command sets up a clean development area.

```bash
git clone ssh://git@gitlab.cern.ch:7999/<yourname>/TRExFitter.git
```

--------------------------------

### TRExFitter Configuration - Job Block

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines global settings for a TRExFitter analysis job. Specify analysis name, center-of-mass energy, point of interest, input source, and output options.

```config
Job: "MyAnalysis"
  CmeLabel: "13 TeV"
  POI: "mu_signal"
  ReadFrom: HIST
  HistoPath: "inputs/"
  Label: "My Analysis"
  LumiLabel: "140 fb^{-1}"
  Lumi: 140000
  MCstatThreshold: 0.01
  SystPruningShape: 0.01
  SystPruningNorm: 0.01
  DebugLevel: 1
  ImageFormat: "png"
  DoSummaryPlot: TRUE
  DoTables: TRUE
```

--------------------------------

### Decorrelate Systematic by Sample

Source: https://context7.com/trexstats/trexfitter/llms.txt

Configure a systematic uncertainty to be decorrelated across different samples. Specify suffix for up/down variations.

```plaintext
Systematic: "Modelling"
  Title: "Modelling"
  Type: HISTO
  Samples: ttbar,singletop
  HistoNameSufUp: "_model_up"
  HistoNameSufDown: "_model_down"
  Decorrelate: SAMPLE
```

--------------------------------

### Configure Unfolding Details

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define specific parameters for the unfolding process, including truth distribution details and binning.

```plaintext
Unfolding: "pT_unfolding"
  MatrixOrientation: TRUTHONHORIZONTAL
  TruthDistributionPath: "truth/"
  TruthDistributionFile: "truth_distributions"
  TruthDistributionName: "h_pT_truth"
  NumberOfTruthBins: 10
  TitleX: "p_{T} [GeV]"
  TitleY: "d#sigma/dp_{T} [pb/GeV]"
  DivideByBinWidth: TRUE
  UnfoldNormXSec: FALSE
```

--------------------------------

### Set Minimum CMake Version

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Specifies the minimum CMake version required for the project. Ensure your CMake version meets this requirement.

```cmake
cmake_minimum_required( VERSION 3.10 )
```

--------------------------------

### Override TRExFitter Configuration via Command Line

Source: https://context7.com/trexstats/trexfitter/llms.txt

Modify analysis parameters such as regions, samples, and systematics directly from the command line. This allows for quick adjustments without editing configuration files.

```bash
# Select specific regions
trex-fitter hwf config/fit.config "Regions=SR1,SR2"
```

```bash
# Select specific samples
trex-fitter hwf config/fit.config "Samples=ttbar,signal"
```

```bash
# Select specific systematics
trex-fitter hwf config/fit.config "Systematics=JES,JER"
```

```bash
# Exclude regions/samples
trex-fitter hwf config/fit.config "Exclude=VR1,VR2"
```

```bash
# Run specific LH scan step (for parallelization)
trex-fitter x config/fit.config "LHscanStep=5"
```

```bash
# Override debug level
trex-fitter hwf config/fit.config "DebugLevel=2"
```

```bash
# Run ranking for specific NPs
trex-fitter r config/fit.config "Ranking=JES,JER,BTag"
```

```bash
# Set constant parameters
trex-fitter f config/fit.config "ConstNFs=mu_bkg:1.0"
```

```bash
# Force recreation of binning files
trex-fitter h config/fit.config "RecreateBinningFiles=TRUE"
```

--------------------------------

### TRExFitter Configuration - Fit Block

Source: https://context7.com/trexstats/trexfitter/llms.txt

Configures the fitting procedure. Specify fit type, region, and options for the point of interest (POI) and Minuit.

```config
Fit: "myfit"
  FitType: SPLUSB
  FitRegion: CRSR
  POIAsimov: 1
  UseMinos: mu_signal
  FitBlind: FALSE
```

--------------------------------

### TRExFitter Ntuple Configuration - Systematic Block (Weight)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a systematic uncertainty based on weights for ntuple analysis. Specify title, type, sample association, and weight suffixes for variations.

```config
Systematic: "BTagSF"
  Title: "b-tagging SF"
  Type: HISTO
  Samples: all
  WeightSufUp: "sf_btag_up/sf_btag"
  WeightSufDown: "sf_btag_down/sf_btag"
  Symmetrisation: TWOSIDED
```

--------------------------------

### TRExFitter Configuration - Region Block (Signal)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a signal region for the analysis. Specify histogram name, variable title, and binning.

```config
Region: "SignalRegion"
  Type: SIGNAL
  HistoName: "h_mtt_SR"
  VariableTitle: "m_{tt} [GeV]"
  Label: "Signal Region"
  Binning: 200,400,600,800,1000,1500
```

--------------------------------

### Set C++ Warning Flags

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Configures the C++ compiler warning flags to enhance code quality and catch potential issues. Includes common flags like -Wall, -Wextra, and optimization flags.

```cmake
set( CMAKE_CXX_FLAGS "-Wall -Wextra -Wshadow -pedantic -O3 -g -fPIC" )
```

--------------------------------

### TRExFitter Configuration - Systematic Block (Overall)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines an overall systematic uncertainty. Specify title, type, up/down variations, samples, and category.

```config
Systematic: "Lumi"
  Title: "Luminosity"
  Type: OVERALL
  OverallUp: 0.02
  OverallDown: -0.02
  Samples: all
  Category: Instrumental
```

--------------------------------

### TRExFitter Configuration - Region Block (Control)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a control region for the analysis. Specify histogram name, variable title, and binning.

```config
Region: "ControlRegion"
  Type: CONTROL
  HistoName: "h_mtt_CR"
  VariableTitle: "m_{tt} [GeV]"
  Label: "Control Region"
  Binning: 200,400,600,800,1000
```

--------------------------------

### Add UnfoldingCode Subdirectory

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Includes the UnfoldingCode directory as a subdirectory, allowing its CMakeLists.txt to be processed and its targets to be built.

```cmake
include_directories( UnfoldingCode )
add_subdirectory( UnfoldingCode )
```

--------------------------------

### TRExFitter Ntuple Configuration - Systematic Block (Ntuple Name)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a systematic uncertainty using different ntuple names for variations in ntuple-based analysis. Specify title, type, sample association, and ntuple names for up/down variations.

```config
Systematic: "JES_NP1"
  Title: "JES NP1"
  Type: HISTO
  Samples: all
  NtupleNameUp: "JES_NP1__1up"
  NtupleNameDown: "JES_NP1__1down"
  Smoothing: 40
```

--------------------------------

### TRExFitter Configuration - NormFactor Block (Background)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a normalization factor for a background sample. Specify title, nominal value, range, and associated samples.

```config
NormFactor: "mu_ttbar"
  Title: "k_{t#bar{t}}"
  Nominal: 1
  Min: 0.5
  Max: 1.5
  Samples: ttbar
```

--------------------------------

### Configure Unfolding Systematic

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define systematic uncertainties for unfolding, specifying up/down variations of the response matrix.

```plaintext
UnfoldingSystematic: "JES_unfold"
  Title: "JES"
  Type: HISTO
  Samples: ttbar_unfold
  ResponseMatrixNameUp: "h_response_JES_up"
  ResponseMatrixNameDown: "h_response_JES_down"
  Symmetrisation: TWOSIDED
```

--------------------------------

### TRExFitter Configuration - NormFactor Block (Signal)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a normalization factor for a sample. Specify title, nominal value, range, and associated samples.

```config
NormFactor: "mu_signal"
  Title: "#mu_{signal}"
  Nominal: 1
  Min: 0
  Max: 5
  Samples: Signal
```

--------------------------------

### Set Policy CMP0077

Source: https://github.com/trexstats/trexfitter/blob/master/CMakeLists.txt

Sets CMake policy CMP0077 to NEW. This policy relates to the behavior of find_package when a package is not found.

```cmake
set(CMAKE_POLICY_DEFAULT_CMP0077 NEW)
```

--------------------------------

### Decorrelate Systematic by Region

Source: https://context7.com/trexstats/trexfitter/llms.txt

Configure a systematic uncertainty to be decorrelated across different regions. Specify suffix for up/down variations.

```plaintext
Systematic: "JES_regional"
  Title: "JES"
  Type: HISTO
  Samples: all
  HistoNameSufUp: "_JES_up"
  HistoNameSufDown: "_JES_down"
  Decorrelate: REGION
```

--------------------------------

### Configure Normalization Factor for Morphing

Source: https://context7.com/trexstats/trexfitter/llms.txt

Define a normalization factor used in morphing, specifying its title, nominal value, and limits.

```plaintext
NormFactor: "mass"
  Title: "Signal Mass"
  Nominal: 750
  Min: 500
  Max: 1000
```

--------------------------------

### TRExFitter Configuration - Systematic Block (Histo)

Source: https://context7.com/trexstats/trexfitter/llms.txt

Defines a histogram-based systematic uncertainty. Specify title, type, sample association, histogram suffix for variations, smoothing, symmetrisation, and category.

```config
Systematic: "JES"
  Title: "Jet Energy Scale"
  Type: HISTO
  Samples: all
  HistoNameSufUp: "_JES_up"
  HistoNameSufDown: "_JES_down"
  Smoothing: 40
  Symmetrisation: TWOSIDED
  Category: Instrumental
```

--------------------------------

### Link commits to JIRA tickets

Source: https://github.com/trexstats/trexfitter/blob/master/CONTRIBUTING.md

You can automatically link your commits and merge requests to JIRA tickets by including the ticket ID in the commit message. This will create a comment on the corresponding JIRA ticket.

```bash
git commit -m "Working on TTHFITTER-102 - Fixing some pointer initialisation"
```

```bash
Closes TTHFITTER-102
Resolves TTHFITTER-102
Fixes TTHFITTER-102
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.