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GEARS | 齿轮组

Geant4 Example Application with Rich features and Small footprints

Download this project as a .zip file Download this project as a tar.gz file

Compile gears Install gears Install Geant4 Install ROOT Docker image Apptainer image

GEARS can run in three major operating systems: Windows, macOS, and Linux. It depends on Geant4. If you don’t have Geant4 installed yet in your system, please install Geant4 first. However, if you have Docker installed on Windows, MacOS, Linux, or Apptainer/Singularity installed on Linux, you can run GEARS in a container where Geant4 has been installed, which can save you a lot of hassle. Please check the Docker/ and Apptainer/ folders for detailed instruction if you are interested in using containerized GEARS.


Get GEARS in Windows

GEARS can be downloaded as a .zip file from its homepage or GitHub. Unpack it and that’s it, you’ve got GEARS.

If you know how to use Git, you can download the whole GEARS repository from GitHub using either GitHub Desktop or Visual Studio. If you use Visual Studio, read Compile GEARS with Visual Studio for detailed instruction.

Get GEARS in macOS or Linux

GEARS can be downloaded as a .tar.gz or .zip file from its homepage or GitHub. Run the following commands in your terminal to unzip it:

$ unzip # if you downloaded the zip file
$ tar xfvz jintonic-gears-commitID.tar.gz # if you download the tar.gz file
$ mv jintonic-gears-commitID gears # rename the directory

If you know how to use Git, you can download the whole GEARS repository from GitHub:

$ git clone

This way, you can update your local copy from time to time using

$ cd /path/to/gears
$ git pull

Note that if you change some files in your local working copy, the git pull command will fail since Git does not want to overwrite your local modification with the updated GEARS. To avoid this, please copy example macros to somewhere outside of the gears/ directory. You can then modify them as you like without worry. An easy way to check if there is any local change that may block git pull is:

$ git status # show modified files
$ git diff a/changed/local/file # show what are changed
$ git checkout -- a/changed/local/file # discard the local change
$ git pull # get latest gears

Compile GEARS

Two compilation systems are provide for GEARS. One is CMake. This mechanism is provided to insure that GEARS can be compiled across platforms. You can find a CMakeLists.txt file in the GEARS folder, which can be detected automatically by CMake in all platforms or Visual Studio in Windows. The other method is to directly use a Makefile shipped with GEARS, which simplifies the compilation in Linux and macOS significantly.

Compile GEARS in Windows

Please download Visual Studio Community Edition installer. Run it. Choose to install a workload called “Desktop development with C++”. It is about 2 GB and takes a long time to download and install. When you open VS the first time, choose “Visual C++” as your “Development Settings”.

The compilation of GEARS can be done solely with Visual Studio. However, the process would become much easier if we use CMake before using Visual Studio.

Compile GEARS in Linux

GEARS is shipped with a simple Makefile. Simply type make to compile to generate a tiny executable gears in the GEARS directory:

$ cd /path/to/gears
$ make # compile to generate executable: gears

Compile GEARS in macOS

You need to have the commandline tools for developers installed before you can compile GEARS in macOS. The command to install that is:

$ xcode-select --install

After this, the procedure is the same as that in Linux.

Install GEARS

Install GEARS in Windows

If you compiled GEARS using CMake and then Visual Studio, you don’t have to do anything extra, gears.exe has been installed automatically for you. If you only used Visual Studio to compile GEARS, please follow the instruction here.

Install GEARS in macOS or Linux

After the compilation, the following message will be shown in your terminal:

$ cd /path/to/gears
$ make # compile to generate executable: gears
 To install, please add the following line
    source /path/to/gears/
 to ~/.bashrc in Linux or ~/.bash_profile in a Mac
 (or ~/.zshrc if you use zsh instead of bash)

Follow this instruction, open a new terminal when you are done, and you should be able to use the gears command in a new terminal now.

For Mac users, you need to use ~/.bash_profile instead of ~/.bashrc. Please check this article for explanation. Alternatively, you can add source ~/.bashrc in your ~/.bash_profile and still add source /path/to/gears/ to ~/.bashrc.

If you use zsh instead of bash, use ~/.zshrc instead of ~/.bashrc or ~/.bash_profile.