GMSH

What is it?

GMSH is an open-source software for 2D/3D mesh and data visualization, developped in Belgium by (mainly) C. Geuzaine and J-F. Remacle.

Install (without being root!)

From scratch (advanced users)

Source code are available on Onelab’s Gitlab and GMSH can be compiled by hand.

Direct install (recommended)

The easiest way to install GMSH is to simply download the binary files for Linux/Windows/Mac, either Stable or Latest automatic Gmsh snapshot (recommended (by me)). The binary file gmsh is located in bin/gmsh in the compressed downloaded file. You can launch it directly

cd folder/of/gmsh/bin
./gmsh

Apart from (maybe) the color theme, a new window should have been launched and looks like this

Add gmsh to your $PATH

For Linux (and Mac) users, it might be convenient to be able to launch GMSH in a terminal and from whichever folder. To do that, simply add to the $PATH environment variable, the path to gmsh’s folder. This can be automated by adding a line in $HOME/.bash_profile (or $HOME/.profile or …)

export PATH=$PATH:/path/to/gmsh

You must rerun your shell to get the changes applied (or usr source command).

[Beginnner] How to manage your files?

A question that quickly arises is:

Where and how do I store every binary and lib files without making my computer a full mess?

Good question.

There are multiple answers and here you’ll find one which you may like (or not). I like to have a $HOME/install folder (local to my account, thus) which mimic the /usr/ folder, i.e. containing bin, lib, share and include folders:

$HOME/install
      └── bin/      # binary files
          └── gmsh    #some binaries (gmsh, ...)
      └── lib/      # library files
          └── gmsh.py
          └── libgmsh.so
      └── share/      # dynamic libraries
      └── include/    # header files

I then set the $PATH environment variable to

export PATH=$PATH:$HOME/install/bin

Every time I add a new file to $HOME/install/bin it becomes accessible, without having to change the environment variable.

API

GMSH provides a powerful API compatible with Python, Julia or C++. The GMSH SDK¹ is available online and easy to install.

Local in the folder (meh)

For example on Unix system and for Python, a way to install it locally (without being root) and by hand ("à la hussarde") is to add this in this in the header of your Python file

import sys
sys.path.insert(0, "/path/to/sdk/lib")
import gmsh

Permanent linking (better)

A better method is to use the $PYTHONPATH environment variable and set it to the SDK’s folder. Following the previous paragraph, create a folder install at your $HOME folder and copy the content of lib folder of the SDK’s zip file inside $HOME/install/lib. You would then have this stucture

$HOME/install
      └── lib/      # library files
          └── gmsh.py
          └── libgmsh.so

You have now to add to Python the path:

export PYTHONPATH=$HOME/install/lib

A relaunch of the terminal might be necessary to take these changes into account. In your Python code, you juste have to import gmsh without any other condition

import gmsh