Merge branch 'feature/detailed-install' into 'migration'

Add instructions for manual install

See merge request !42

README.md

@@ -42,43 +42,52 @@ source tools/setup.sh
 
 ### Method \#2: By hand, step by step
 
-*Work in progress*
-
-<!---
-In the following, we explain the installation of the framework step by step. A few packages external to CMSSW are necessary (e.g. TUnfold), which you will need to tell CMSSW how to find them with `scram setup`.
-
-First source your CMSSW release and close to a directory where you want to install the external packages.
-1. Install TUnfold:
-```
-wget https://www.desy.de/~sschmitt/TUnfold/TUnfold_V17.9.tgz
-mkdir -p TUnfold TUnfold/lib
-mv TUnfold_V17.9.tgz TUnfold
-cd TUnfold
-tar xvzf TUnfold_V17.9.tgz
-make lib TUNFOLDVERSION='V17' -j
-mv -f libunfold.so lib/libtunfold.so
-mv -f TUnfoldV17Dict_rdict.pcm lib/
-(cd $CMSSW_BASE && scram setup $OLDPWD/../tunfold.xml)
-```
-2. Tell CMSSW where to find libgit2:
+The instructions below assume that you have an environment with all the required dependencies or that you know how to install them if CMake complains that they are missing. Recent LCG environments do not require additional setup. They build the software without any special flags, so the compiler will use no optimization and include basic debugging information. You can pass additional settings using the `CMAKE_BUILD_TYPE` variable.
+ 
+We will install the packages in order, starting with Darwin then following with Core. First, we create two folders, one that will contain the build artifacts and one that will contain the installed software. For convenience, we store their location in variables:
+```sh
+# readlink makes the paths absolute
+BUILD_DIR=$(readlink -f ./build)
+INSTALL_DIR=$(readlink -f ./install)
+mkdir -p $BUILD_DIR $INSTALL_DIR
 ```
-(cd $CMSSW_BASE && scram setup $OLDPWD/libgit2.xml)
-```
-3. Install Darwin:
-```
-git clone https://gitlab.cern.ch/Proto/Darwin.git
-cmake3 -B build -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$PWD/build/install
-cmake3 --build build -j`nproc`
-cmake3 --build build --target install
-(cd $CMSSW_BASE && scram setup $OLDPWD/../darwin.xml)
+
+The first step is then to download, compile, and install Darwin:
+```sh
+git clone https://gitlab.cern.ch/Proto/Darwin.git                         # download
+cmake -B $BUILD_DIR/Darwin -S Darwin -DCMAKE_INSTALL_PREFIX=$INSTALL_DIR  # configure
+cmake --build $BUILD_DIR/Darwin --target install -j$(nproc)               # build and install
 ```
-4. If you want to rerun jet clustering (e.g. to have AK8 jets at a low transverse momentum), you need to clone the branch `jetToolbox_120X` from the [JetToolbox](https://github.com/cms-jet/JetToolbox.git), and apply a minor patch with the following commands:
+
+We then do the same for Core:
+```sh
+git clone https://gitlab.cern.ch/cms-analysis/general/DasAnalysisSystem/Core.git  # download
+cmake -B $BUILD_DIR/Core -S Core -DCMAKE_INSTALL_PREFIX=$INSTALL_DIR              # configure
+cmake --build $BUILD_DIR/Core --target install -j$(nproc)                         # build and install
 ```
-cd $CMSSW_BASE/src/JMEAnalysis/JetToolbox
-patch -p1 $OLDPWD/jetToolbox_120X.patch
+
+Finally, we clone the respository containing scale factors and other corrections:
+```sh
+git clone --recursive https://gitlab.cern.ch/cms-analysis/general/DasAnalysisSystem/tables.git
 ```
-5. Clone the `Tables` wherever you like and the `Core` in CMSSW, and compile as usual with `scram b -j`.
--->
+
+This gives us an installation of both Darwin and Core in the install folder. You need to set a few environment variables before you can use them:
+
+| Variable | Value |
+|:-|:-|
+| `PATH` | `$BUILD_DIR/bin:$PATH` |
+| `LD_LIBRARY_PATH` | `$BUILD_DIR/lib64:$LD_LIBRARY_PATH` (note: can be different on some systems) |
+| `PYTHONPATH` | `$BUILD_DIR/python:$PYTHONPATH` |
+| `DARWIN_FIRE_AND_FORGET` | `$BUILD_DIR/lib64` (note: can be different on some systems) | 
+
+In addition, we recommend setting variables for the location of the various repositories:
+| Variable | Value |
+|:-|:-|
+| `DAS_BASE` | `$PWD` |
+| `DARWIN_BASE` | `$PWD/Darwin` |
+| `CORE_BASE` | `$PWD/Core` |
+| `DARWIN_TABLES` | `$PWD/tables` |
+
 
 ### With `micromamba`