CAMB internally uses modern (object-oriented) Fortran 2008 for most numerical calculations, and needs a recent fortran compiler to build the numerical library. The recommended compilers are
- gfortran version 6.3 or higher
- Intel Fortran (ifort), version 18.0.1 or higher (some things may work with version 14+)
The gfortran compiler is part of the standard “gcc” compiler package, and may be pre-installed on recent unix systems. Check the version using “gfortran –version”.
If you do not have a suitable Fortran compiler, you can get one as follows:
Download the binary installation
Download gfortran as part of MinGW-w64 (select x86_64 option in the installation program)
To install from the standard repository use:
On Ubuntu systems where the default gfortran is too old, you can use this to install a later version
To make this the default gfortran then use
To re-use next time, add gfortran-symlinks directory to your startup settings (.bashrc).
Alternatively you can compile and run in a container or virtual machine: e.g., see CosmoBox. For example, to run a configured shell in docker where you can install and run camb from the command line (after changing to the camb directory):
docker run -v /local/git/path/CAMB:/camb -i -t cmbant/cosmobox
Updating and modified Fortran code¶
In the main CAMB source root directory, to re-build the Fortran binary including any pulled or local changes use:
python setup.py make
This will also work on Windows as long as you have MinGW-w64 installed as described above.
Note that you will need to close all python instances using camb before you can re-load with an updated library. This includes in Jupyter notebooks; just re-start the kernel or use:
import IPython IPython.Application.instance().kernel.do_shutdown(True)
If you want to automamatically rebuild the library from Jupyter you can do something like this:
import subprocess import sys import os src_dir = '/path/to/git/CAMB' try: subprocess.check_output(r'python "%s" make'%os.path.join(src_dir, 'setup.py'), stderr=subprocess.STDOUT) sys.path.insert(0,src_dir) import camb print('Using CAMB %s installed at %s'%(camb.__version__, os.path.dirname(camb.__file__))) except subprocess.CalledProcessError as E: print(E.output.decode())