Hello, I compiled numpy-1.3.0 from sources on Ubuntu-hardy, x86-64 (Intel) with MKL. This is my site.cfg: [mkl] # library_dirs = /opt/intel/mkl/10.0.1.014/lib/32/ library_dirs = /opt/intel/mkl/10.2.2.025/lib/em64t include_dirs = /opt/intel/mkl/10.2.2.025/include lapack_libs = mkl_lapack #mkl_libs = mkl_core, guide, mkl_gf_ilp64, mkl_def, mkl_gnu_thread, iomp5, mkl_vml_mc3 mkl_libs = guide, mkl_core, mkl_gnu_thread, iomp5, mkl_gf_ilp64, mkl_mc3, mkl_def In [2]: numpy.test() Running unit tests for numpy NumPy version 1.3.0 NumPy is installed in /opt/********************* Python version 2.5.2 (r252:60911, Jul 22 2009, 15:33:10) [GCC 4.2.4 (Ubuntu 4.2.4-1ubuntu3)] nose version 0.11.0 .......... MKL ERROR: Parameter 4 was incorrect on entry to DGESV MKL ERROR: Parameter 4 was incorrect on entry to DGESV MKL ERROR: Parameter 4 was incorrect on entry to DGESV MKL ERROR: Parameter 4 was incorrect on entry to DGESV MKL ERROR: Parameter 4 was incorrect on entry to DGESV MKL ERROR: Parameter 4 was incorrect on entry to DGESV .. MKL ERROR: Parameter 4 was incorrect on entry to DGESV FSegmentation fault I am using gcc: gcc -v Using built-in specs. Target: x86_64-linux-gnu Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.2 --program-suffix=-4.2 --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --enable-mpfr --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu4) Anyone having the same issues? Do I have the mkl_libs correctly configured (this seems like a black art!) Thanks, Ashwin