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Saturday, 12 March 2016


A small tap for the Homebrew project to install Julia. Installation instructions:
$ brew update
$ brew tap staticfloat/julia
$ brew install julia

Common Issues

If you are building Julia from source and you see errors about libgfortran.dylib, you most likely need to reinstall the latest gccopenblas-juliasuite-sparse-julia and arpack-julia:
$ brew update
$ brew rm gcc openblas-julia suite-sparse-julia arpack-julia
$ brew install gcc openblas-julia suite-sparse-julia arpack-julia 
See this thread for technical details as to why gfortran dependencies require this treatment.

Building a bleeding-edge version of Julia

If you wish to test the newest development version of Julia, you can build with the --HEAD option:
$ brew install --HEAD julia
Note that to run the test suite you must also pass the --HEAD option to brew:
$ brew test -v --HEAD julia

Using OpenBLAS HEAD or specifying CPU targets

If you wish to test the newest development version of OpenBLAS with Julia, you can do so by manually unlinking OpenBLAS, and installing the HEAD version of the formula:
$ brew unlink openblas-julia
$ brew install openblas-julia --HEAD
This will install the latest develop branch of OpenBLAS. Julia will happily link against this new version, but unfortunately SuiteSparse will not, so we must recompile SuiteSparse and therefore Julia:
$ brew rm suite-sparse-julia julia
$ brew install julia
When installing OpenBLAS on that shiny new piece of hardware that just came out, note that OpenBLAS may not have the software available to autodetect your processor type. You can manually specify a CPU target architecture by specifying --target when building OpenBLAS. For instance, to specify the Sandybridge archiceture (a good fallback for most modern macs):
$ brew install openblas-julia --target=SANDYBRIDGE

Rebuilding the system image

When building Julia, the file base/userimg.jl, if it exists, will be included in the cached of compiled code. If there are large libraries that you use often, it can be useful to require those in this file, for example:
By default, the userimg.jl file does not exist, but you can create it yourself and then rebuild the Julia system image. Place a userimg.jl file into /usr/local/Cellar/julia/<julia version>/share/julia/base (Assuming Homebrew has been installed to /usr/local), then run build_sysimg.jl (located in the folder immediatebly above the base directory) to rebuild the system image. The script has many options, to see them all run ./build_sysimg.jl --help, but if you just want to replace the current system image with the new one you're about to build (and most people do just want that) simply run:
$ ./build_sysimg.jl --force

Upgrading Julia

To upgrade Julia, remove and reinstall (Typically you will be doing this when living on the latest development version, so we have included all --HEAD commands here):
$ brew rm julia
$ brew install --HEAD julia
Run tests after upgrading to make sure everything is functioning as expected. Even when Julia is able to build, the tests might still fail due to dependencies.
$ brew test -v --HEAD julia
If compilation of Julia fails, or the tests fail, you may have to remove these dependencies and recompile:
$ brew rm julia arpack-julia suite-sparse-julia openblas-julia
$ brew install -v --HEAD julia && brew test -v --HEAD julia
This procedure is necessary after upgrading gcc, as the location of the gfortran libraries changes.