home.md

+The LCGSoft package allows distribution/installations of external generator packages
+identical to the official LCGCMT releases for supported platforms. 
+
+Please note that each LCGCMT release has its own set of supported platforms. The
+list of LCG CMT Releases is avalaible [here](http://lcgsoft.web.cern.ch/lcgsoft/).
+
+LCGsoft supports LCGCMT releases starting from 65.
+
+Briefly speaking, LCGSoft perfoms the following actions:
+
+1. Take source external/generators tarballs from the AFS directories:
+
+    `/afs/cern.ch/sw/lcg/external/tarFiles/` - for externals;
+    
+    `/afs/cern.ch/sw/lcg/external/tarFiles/MCGeneratorsTarFiles` - for generators;
+
+    with the corresponding http access:
+
+    <http://service-spi.web.cern.ch/service-spi/external/tarFiles/>
+    
+    <http://service-spi.web.cern.ch/service-spi/external/tarFile/MCGeneratorsTarFiles>
+
+2. Untar source files and apply patches if needed. The patches applied can be found here: [externals](externals/patches/), [projects](projects/patches/), [pyexternals](pyexternals/patches/) [gridexternals](gridexternals/patches/) [generators](generators/patches/)
+
+    Each patch has a package version as a part of patch file name, it is applied only to this version.
+
+3. Then LCGSoft package executes a set of actions using the macro based on cmake LCGPackage_Add. Default actions, performed automatically:
+    * add the log files to the install area 
+    * add the sources to the install area
+    * create a binary tarball
+    * strip rpath from .so files    
+
+    A typical set of directives for the generator package configuration and installation steps (first 
+impression that it is complicated but it is not) looks like this:
+
+    ```
+#---lhapdf6------------------------------------------------------------------------------------------
+    LCGPackage_Add(
+      lhapdf6
+      URL ${gen_url}/LHAPDF-<NATIVE_VERSION>.tar.gz
+      CONFIGURE_COMMAND ./configure
+         --prefix=<INSTALL_DIR>
+         --with-boost=${Boost_home}
+         --with-yaml-cpp=${yamlcpp_home}
+         PYTHON=${Python_home}/bin/python
+         CYTHON=${cython_home}/bin/cython
+         PYTHONPATH=${cython_pythonpath}  CFLAGS=-O2 CXXFLAGS=-O2 FCFLAGS=-O2 LDFLAGS=-O2
+      BUILD_COMMAND ${MAKE} all
+      ${library_path}=${yamlcpp_home}/lib:$ENV{${library_path}} PYTHONPATH=${cython_pythonpath} LIBRARY_PATH=${Python_home}/lib
+      BUILD_IN_SOURCE 1
+      INSTALL_COMMAND make install PYTHONPATH=${cython_pythonpath} LIBRARY_PATH=${Python_home}/lib
+              COMMAND ${CMAKE_COMMAND} -DINSTALL_DIR=<INSTALL_DIR> -P ${CMAKE_SOURCE_DIR}/cmake/scripts/StripLib.cmake
+      DEPENDS Boost yamlcpp Python cython
+    )
+    ```
+
+    The `URL` and `CONFIGURE_COMMAND` directives are obligatory, others are optional.
+    The directive names are more or less self-explainatory. User can easily change them according to his/her own needs.
+
+
+    The LCGSoft package has a system of different level tests. The corresponding instructions are [here][CTests].