Hi, While updating sage and python to 4.7 and 2.7, I hit a variation of an old bug (see http://bugs.gentoo.org/195619): scipy compiles with lapack-reference but is unusable. Running in python import scipy.optimize fails with [...] from scipy.linalg import clapack ImportError: /usr/lib64/python2.7/site-packages/scipy/linalg/clapack.so: undefined symbol: clapack_sgesv I tried rebuilding numpy and scipy with lapack provided (eselect) by lapack-reference, blas provided by blas-reference, cblas provided by gsl and with/without clapack with the same result. Then I tried rebuilding numpy and scipy with lapack, blas and cblas provided (eselect) by atlas and scipy worked flawlessly. Should scipy depend on a specific lapack provider instead of a virtual? Enable it at compile time? Is it an unfortunate combination what fails? I can provide build logs if you need them. Best, Marc.