Hi all, Upon experimenting with Joe’s python3 version of kwant on OS X I found that mumps has a well maintained homebrew formula of its own in the homebrew/science tap: https://github.com/Homebrew/homebrew-science/blob/master/mumps.rb I think it might be useful to simplify the kwant installation on OS X. Also the tinyarray and kwant version are outdated on https://github.com/michaelwimmer/homebrew-kwant Updating tinyarray via pip doesn’t work: bnijholt:~> pip install tinyarray -U Collecting tinyarray Installing collected packages: tinyarray Found existing installation: tinyarray 1.0.2 DEPRECATION: Uninstalling a distutils installed project (tinyarray) has been deprecated and will be removed in a future version. This is due to the fact that uninstalling a distutils project will only partially uninstall the project. Uninstalling tinyarray-1.0.2: Successfully uninstalled tinyarray-1.0.2 Rolling back uninstall of tinyarray Exception: Traceback (most recent call last): File "/usr/local/lib/python2.7/site-packages/pip/basecommand.py", line 223, in main status = self.run(options, args) File "/usr/local/lib/python2.7/site-packages/pip/commands/install.py", line 299, in run root=options.root_path, File "/usr/local/lib/python2.7/site-packages/pip/req/req_set.py", line 646, in install **kwargs File "/usr/local/lib/python2.7/site-packages/pip/req/req_install.py", line 813, in install self.move_wheel_files(self.source_dir, root=root) File "/usr/local/lib/python2.7/site-packages/pip/req/req_install.py", line 1008, in move_wheel_files isolated=self.isolated, File "/usr/local/lib/python2.7/site-packages/pip/wheel.py", line 339, in move_wheel_files clobber(source, lib_dir, True) File "/usr/local/lib/python2.7/site-packages/pip/wheel.py", line 317, in clobber shutil.copyfile(srcfile, destfile) File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 83, in copyfile with open(dst, 'wb') as fdst: IOError: [Errno 13] Permission denied: '/usr/local/lib/python2.7/site-packages/tinyarray.so' Changing the kwant tarball to the 1.0.4 file on the brew formula also doesn’t work (https://github.com/basnijholt/homebrew-kwant/blob/master/kwant.rb): bnijholt:~> brew install kwant ==> Installing kwant from basnijholt/homebrew-kwant ==> Using Homebrew-provided fortran compiler. This may be changed by setting the FC environment variable. ==> Building with an alternative Fortran compiler This is unsupported. Warning: No Fortran optimization information was provided. You may want to consider setting FCFLAGS and FFLAGS or pass the `--default-fortran-flags` option to `brew install` if your compiler is compatible with GCC. If you like the default optimization level of your compiler, ignore this warning. ==> Downloading pypi.python.org/packages/source/k/kwant/kwant-1.0.4.tar.gz Already downloaded: /Library/Caches/Homebrew/kwant-1.0.4.tar.gz ==> Patching patching file build.conf ==> python setup.py install --prefix=/usr/local/Cellar/kwant/1.0.4 Build configuration was: User-configured LAPACK and BLAS User-configured MUMPS ********************************************************************** error: command 'clang' failed with exit status 1 READ THIS: https://git.io/brew-troubleshooting If reporting this issue please do so at (not Homebrew/homebrew): https://github.com/basnijholt/homebrew-kwant/issues Best Bas