Hello! I am trying to build numpy 1.6.2 with python 2.7 in Ubuntu 12.04 and wish to link against serial ATLAS rather than the threaded version. I have modified site.cfg accordingly by uncommenting out the following lines: [blas_opt] libraries = f77blas, cblas, atlas [lapack_opt] libraries = lapack, f77blas, cblas, atlas However when I run python setup.py build it still links to the threaded versions eg. python setup.py build Running from numpy source directory.F2PY Version 2 blas_opt_info: blas_mkl_info: libraries mkl,vml,guide not found in /usr/local/lib libraries mkl,vml,guide not found in /usr/lib NOT AVAILABLE atlas_blas_threads_info: Setting PTATLAS=ATLAS libraries ptf77blas,ptcblas,atlas not found in /usr/local/lib Setting PTATLAS=ATLAS customize GnuFCompiler Could not locate executable g77 Could not locate executable f77 customize IntelFCompiler Could not locate executable ifort Could not locate executable ifc customize LaheyFCompiler Could not locate executable lf95 customize PGroupFCompiler Could not locate executable pgfortran customize AbsoftFCompiler Could not locate executable f90 customize NAGFCompiler Found executable /usr/bin/f95 customize VastFCompiler customize CompaqFCompiler Could not locate executable fort customize IntelItaniumFCompiler Could not locate executable efort Could not locate executable efc customize IntelEM64TFCompiler customize Gnu95FCompiler Found executable /usr/bin/gfortran customize Gnu95FCompiler customize Gnu95FCompiler using config compiling '_configtest.c': /* This file is generated from numpy/distutils/system_info.py */ void ATL_buildinfo(void); int main(void) { ATL_buildinfo(); return 0; } C compiler: gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fPIC compile options: '-c' gcc: _configtest.c gcc -pthread _configtest.o -L/usr/lib/atlas-base -lptf77blas -lptcblas -latlas -o _configtest ATLAS version 3.8.4 built by buildd on Sat Sep 10 23:12:12 UTC 2011: UNAME : Linux crested 2.6.24-29-server #1 SMP Wed Aug 10 15:58:57 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux INSTFLG : -1 0 -a 1 ARCHDEFS : -DATL_OS_Linux -DATL_ARCH_HAMMER -DATL_CPUMHZ=1993 -DATL_USE64BITS -DATL_GAS_x8664 F2CDEFS : -DAdd_ -DF77_INTEGER=int -DStringSunStyle CACHEEDGE: 393216 F77 : gfortran, version GNU Fortran (Ubuntu/Linaro 4.6.1-9ubuntu2) 4.6.1 F77FLAGS : -fomit-frame-pointer -mfpmath=387 -O2 -falign-loops=4 -Wa,--noexecstack -fPIC -m64 SMC : gcc, version gcc (Ubuntu/Linaro 4.6.1-9ubuntu2) 4.6.1 SMCFLAGS : -fomit-frame-pointer -mfpmath=387 -O2 -falign-loops=4 -Wa,--noexecstack -fPIC -m64 SKC : gcc, version gcc (Ubuntu/Linaro 4.6.1-9ubuntu2) 4.6.1 SKCFLAGS : -fomit-frame-pointer -mfpmath=387 -O2 -falign-loops=4 -Wa,--noexecstack -fPIC -m64 success! removing: _configtest.c _configtest.o _configtest Setting PTATLAS=ATLAS FOUND: libraries = ['ptf77blas', 'ptcblas', 'atlas'] library_dirs = ['/usr/lib/atlas-base'] language = c define_macros = [('ATLAS_INFO', '"\\"3.8.4\\""')] include_dirs = ['/usr/include/atlas'] FOUND: libraries = ['ptf77blas', 'ptcblas', 'atlas'] library_dirs = ['/usr/lib/atlas-base'] language = c define_macros = [('ATLAS_INFO', '"\\"3.8.4\\""')] include_dirs = ['/usr/include/atlas'] lapack_opt_info: lapack_mkl_info: mkl_info: libraries mkl,vml,guide not found in /usr/local/lib libraries mkl,vml,guide not found in /usr/lib NOT AVAILABLE NOT AVAILABLE atlas_threads_info: Setting PTATLAS=ATLAS libraries ptf77blas,ptcblas,atlas not found in /usr/local/lib libraries lapack_atlas not found in /usr/local/lib libraries lapack not found in /usr/lib/atlas-base numpy.distutils.system_info.atlas_threads_info Setting PTATLAS=ATLAS Setting PTATLAS=ATLAS FOUND: libraries = ['lapack', 'ptf77blas', 'ptcblas', 'atlas'] library_dirs = ['/usr/lib/atlas-base/atlas', '/usr/lib/atlas-base'] language = f77 define_macros = [('ATLAS_INFO', '"\\"3.8.4\\""')] include_dirs = ['/usr/include/atlas'] FOUND: libraries = ['lapack', 'ptf77blas', 'ptcblas', 'atlas'] library_dirs = ['/usr/lib/atlas-base/atlas', '/usr/lib/atlas-base'] language = f77 define_macros = [('ATLAS_INFO', '"\\"3.8.4\\""')] include_dirs = ['/usr/include/atlas'] ... Any ideas? best, Jared