## CRMC
The program crmc (Cosmic Ray Monte Carlo) is an interface giving access to different cosmic ray and non-cosmic ray event generators by an easy-to-use command line interface. The output can be stored in different formats, i.e. in a ROOT TTree, HepMC event file, or Rivet
output directly. Before this installation, make sure that you have has the newest official HERDOS environment.
```
source /cvmfs/herd.ihep.ac.cn/HERDOS/SLC7/Pre-release/ExternalLibs-GCC8.5.0/bashrc.sh
```
### Installation and use of CRMC

Please refer to [crmc](https://gitlab.iap.kit.edu/AirShowerPhysics/crmc)

#### CRMC dependencies

To install please get the version 2.0.1 and install the following pre-requisites:

1.	fastjet

download：[fastjet-3.4.0.tar.gz](http://fastjet.fr/repo/fastjet-3.4.0.tar.gz)

installation:

```
./configure –prefix= install_directory --enable-shared

make && make install
```

2.	HepMC3

download：[HepMC3-3.2.5.tar.gz](http://hepmc.web.cern.ch/hepmc/releases/HepMC3-3.2.5.tar.gz)

installation：
```
cmake .. -DCMAKE_INSTALL_PREFIX=install_directory
-DHEPMC3_INSTALL_INTERFACES:BOOL=ON -DHEPMC3_PYTHON_VERSIONS=3.8  
-DHEPMC3_Python_SITEARCH38=install_directory/lib/python3.8/site-packages
-DHEPMC3_BUILD_STATIC_LIBS:BOOL=OFF -DHEPMC3_ENABLE_ROOTIO:BOOL=OFF 

make && make install
```
3.	Geant4

download：[v10.5.1.tar.gz](https://github.com/Geant4/geant4/archive/v10.5.1.tar.gz)

   （1） `geant4-10.5.1/source/processes/electromagnetic/utils/src/G4EmParameters.cc`

   **Line 143** :  Change the maximum kinematic energy of the EM processes from 100 TeV to 10 PeV

   ```
   maxKinEnergy = 10.0*CLHEP::PeV;
   ```

   （2）`geant4-10.5.1/source/processes/hadronic/util/src/G4HadronicParameters.cc`

   **Line 63** :  Change the maximum energy of the hadronic processes from 100 TeV to 10 PeV

   ```
   fMaxEnergy = 10.0*CLHEP::PeV;
   ```

   （3）`geant4-10.5.1/source/processes/electromagnetic/standard/src/G4eCoulombScatteringModel.cc`

   **Line 207** :  Change the cross section of the coulomb scatter process above 100 TeV to that of at 100 TeV, add the followed code :

```
if( kinEnergy >= 100.0 * CLHEP::TeV) { kinEnergy = 100.0 *CLHEP::TeV; }
```
installation：

```
cmake .. -DCMAKE_INSTALL_PREFIX=install_directory 
-DGEANT4_BUILD_CXXSTD=14 -DGEANT4_USE_GDML=ON 
-DGEANT4_INSTALL_DATA=ON -DGEANT4_USE_OPENGL_X11=ON 
-DGEANT4_USE_RAYTRACER_X11=ON -DGEANT4_BUILD_MULTITHREADED=ON 
-DGEANT4_USE_SYSTEM_ZLIB=ON -DGEANT4_USE_QT=ON
-DGEANT4_BUILD_TLS_MODEL=global-dynamic 
-DXERCESC_ROOT_DIR=$HERD_EXTLIB_xercesc_HOME

make && make install
```

#### CRMC installation

download：[crmc-v2.0.1](https://gitlab.iap.kit.edu/AirShowerPhysics/crmc/-/archive/v2.0.1/crmc-v2.0.1.tar.gz)

(1) `crmc-v2.0.1/src/geant4/G4HadronicInelasticModelCRMC.cc`  

   **Line 202, 295 and 407**: Initialize the variable ‘pdef_errorcode’ to zero.

    `int pdef_errorcode =0;`
	
   **Line 412**: Correct the variable ‘gCRMC_data’ to the variable ‘CRMC_data’

    `int particle_id = CRMC_data.fPartId[i];`

(2) `crmc-v2.0.1/CMakeLists.txt`

   Comment the **line 468**,

   ```
   TARGET_LINK_LIBRARIES (crmc ${Boost_LIBRARIES})
   ```

Add the followed codes here ,
```
set(BOOST_LIBRARY_DIR $ENV{HERD_EXTLIB_boost_HOME}/lib)
TARGET_LINK_LIBRARIES (crmc 
${BOOST_LIBRARY_DIR}/libboost_filesystem.so
${BOOST_LIBRARY_DIR}/libboost_iostreams.so
${BOOST_LIBRARY_DIR}/libboost_system.so
${BOOST_LIBRARY_DIR}/libboost_program_options.so)
```
(3) `crmc-v2.0.1/src/CRMCtrapfpe.c` ( if ARM architecture)

Change **line 31** from 
   ```
_FPU_DEFAULT & ~(_FPU_MASK_IM | _FPU_MASK_ZM | _FPU_MASK_OM);
```
to
   ```
_FPU_DEFAULT & ~(_FPU_FPCR_MASK_IXE | _FPU_FPCR_MASK_OFE | _FPU_FPCR_MASK_UFE);
``` 

   installation：

   ```
cmake .. -DCMAKE_INSTALL_PREFIX=install_directory
-D__GEANT4__=ON     -D__GEANT4PHYS__=ON   -DCRMC_QGSJET01=ON  
-DCRMC_GHEISHA=ON  -DCRMC_PYTHIA=ON     -DCRMC_HIJING=ON 
-DCRMC_SIBYLL=ON    -DCRMC_PHOJET=ON     -DCRMC_DPMJET19=ON 
-DCRMC_QGSJETII03=ON  -DCRMC_QGSJETII04=ON

make && make install
```

#### Use of CRMC 

`offline/Simulation/SimConfig/HERDSim/src/PhysicsList.cc`

Add codes in `PhysicsList::ConstructProcess()`

```
// 0 - EPOS LHC   1 - EPOS 1.99   12 - DPMJET3  
G4HadronPhysicsCRMC* crmc = new G4HadronPhysicsCRMC(12);
crmc ->SetEnergyThreshold(300.*GeV);
crmc->ConstructProcess();
```