Error while installing numpy in venv
Question: I am getting the following error while trying to install numpy in my venv. I
am running centos. which python points to the python in my venv directory

    
    
        (venv)bash-3.2$ pip install numpy
        Downloading/unpacking numpy
          Running setup.py egg_info for package numpy
        Running from numpy source directory.
        non-existing path in 'numpy/distutils': 'site.cfg'
        F2PY Version 2
        blas_opt_info:
        blas_mkl_info:
          libraries mkl,vml,guide not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64', '/usr/lib']
          NOT AVAILABLE
    
        atlas_blas_threads_info:
        Setting PTATLAS=ATLAS
          libraries ptf77blas,ptcblas,atlas not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64/atlas', '/usr/lib64/sse2', '/usr/lib64', '/usr/lib/sse2', '/usr/lib']
          NOT AVAILABLE
    
        atlas_blas_info:
          libraries f77blas,cblas,atlas not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64/atlas', '/usr/lib64/sse2', '/usr/lib64', '/usr/lib/sse2', '/usr/lib']
          NOT AVAILABLE      /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/numpy/distutils/system_info.py:1494: UserWarning:
            Atlas (http://math-atlas.sourceforge.net/) libraries not found.
            Directories to search for the libraries can be specified in the
            numpy/distutils/site.cfg file (section [atlas]) or by setting
            the ATLAS environment variable.
          warnings.warn(AtlasNotFoundError.__doc__)
        blas_info:
          FOUND:
            libraries = ['blas']
            library_dirs = ['/usr/lib64']
            language = f77
    
          FOUND:
            libraries = ['blas']
            library_dirs = ['/usr/lib64']
            define_macros = [('NO_ATLAS_INFO', 1)]
            language = f77
    
        lapack_opt_info:
        lapack_mkl_info:
        mkl_info:
          libraries mkl,vml,guide not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64', '/usr/lib']
          NOT AVAILABLE
    
          NOT AVAILABLE
    
        atlas_threads_info:
        Setting PTATLAS=ATLAS
          libraries ptf77blas,ptcblas,atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
          libraries lapack_atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
          libraries ptf77blas,ptcblas,atlas not found in /usr/local/lib64
          libraries lapack_atlas not found in /usr/local/lib64
          libraries ptf77blas,ptcblas,atlas not found in /usr/local/lib
          libraries lapack_atlas not found in /usr/local/lib
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib64/atlas
          libraries lapack_atlas not found in /usr/lib64/atlas
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib64/sse2
          libraries lapack_atlas not found in /usr/lib64/sse2
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib64
          libraries lapack_atlas not found in /usr/lib64
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib/sse2
          libraries lapack_atlas not found in /usr/lib/sse2
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib
          libraries lapack_atlas not found in /usr/lib
        numpy.distutils.system_info.atlas_threads_info
          NOT AVAILABLE
    
        atlas_info:
          libraries f77blas,cblas,atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
          libraries lapack_atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
          libraries f77blas,cblas,atlas not found in /usr/local/lib64
          libraries lapack_atlas not found in /usr/local/lib64
          libraries f77blas,cblas,atlas not found in /usr/local/lib
          libraries lapack_atlas not found in /usr/local/lib
          libraries f77blas,cblas,atlas not found in /usr/lib64/atlas
          libraries lapack_atlas not found in /usr/lib64/atlas
          libraries f77blas,cblas,atlas not found in /usr/lib64/sse2
          libraries lapack_atlas not found in /usr/lib64/sse2
          libraries f77blas,cblas,atlas not found in /usr/lib64
          libraries lapack_atlas not found in /usr/lib64
          libraries f77blas,cblas,atlas not found in /usr/lib/sse2
          libraries lapack_atlas not found in /usr/lib/sse2
          libraries f77blas,cblas,atlas not found in /usr/lib
          libraries lapack_atlas not found in /usr/lib
        numpy.distutils.system_info.atlas_info
          NOT AVAILABLE    /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/numpy/distutils/system_info.py:1408: UserWarning:
            Atlas (http://math-atlas.sourceforge.net/) libraries not found.
            Directories to search for the libraries can be specified in the
            numpy/distutils/site.cfg file (section [atlas]) or by setting
            the ATLAS environment variable.
          warnings.warn(AtlasNotFoundError.__doc__)
        lapack_info:
          FOUND:
            libraries = ['lapack']
            library_dirs = ['/usr/lib64']
            language = f77
    
          FOUND:
            libraries = ['lapack', 'blas']
            library_dirs = ['/usr/lib64']
            define_macros = [('NO_ATLAS_INFO', 1)]
            language = f77
    
        build_src
        building py_modules sources
        building library "npymath" sources
        customize Gnu95FCompiler
        Found executable /usr/bin/gfortran
        customize Gnu95FCompiler
        customize Gnu95FCompiler using config
        C compiler: gcc -pthread -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/nlu/users/indrani_gorti/prefix/include -fPIC -fPIC
    
        compile options: '-Inumpy/core/src/private -Inumpy/core/src -Inumpy/core -Inumpy/core/src/npymath -Inumpy/core/src/multiarray -Inumpy/core/src/umath -Inumpy/core/src/npysort -Inumpy/core/include -I/nlu/users/indrani_gorti/prefix/include/python2.7 -c'
        gcc: _configtest.c
        gcc -pthread _configtest.o -o _configtest
        success!
        removing: _configtest.c _configtest.o _configtest
        C compiler: gcc -pthread -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/nlu/users/indrani_gorti/prefix/include -fPIC -fPIC
    
        compile options: '-Inumpy/core/src/private -Inumpy/core/src -Inumpy/core -Inumpy/core/src/npymath -Inumpy/core/src/multiarray -Inumpy/core/src/umath -Inumpy/core/src/npysort -Inumpy/core/include -I/nlu/users/indrani_gorti/prefix/include/python2.7 -c'
        gcc: _configtest.c
        _configtest.c:1: warning: conflicting types for built-in function 'exp'
        gcc -pthread _configtest.o -o _configtest
        _configtest.o: In function `main':
        /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/_configtest.c:6: undefined reference to `exp'
        collect2: ld returned 1 exit status
        _configtest.o: In function `main':
        /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/_configtest.c:6: undefined reference to `exp'
        collect2: ld returned 1 exit status
        failure.
        removing: _configtest.c _configtest.o
        C compiler: gcc -pthread -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/nlu/users/indrani_gorti/prefix/include -fPIC -fPIC
    
        compile options: '-Inumpy/core/src/private -Inumpy/core/src -Inumpy/core -Inumpy/c
        numpy.core - nothing done with h_files = ['build/src.linux-x86_64-2.7/numpy/core/include/numpy/config.h', 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/_numpyconfig.h', 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/__multiarray_api.h', 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/__ufunc_api.h']
        building extension "numpy.core._dotblas" sources
        building extension "numpy.core.umath_tests" sources
        building extension "numpy.core.multiarray_tests" sources
        building extension "numpy.lib._compiled_base" sources
        building extension "numpy.numarray._capi" sources
        building extension "numpy.fft.fftpack_lite" sources
        building extension "numpy.linalg.lapack_lite" sources
          adding 'numpy/linalg/lapack_litemodule.c' to sources.
          adding 'numpy/linalg/python_xerbla.c' to sources.
        building extension "numpy.random.mtrand" sources
        C compiler: gcc -pthread -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/nlu/users/indrani_gorti/prefix/include -fPIC -fPIC
    
        compile options: '-Inumpy/core/src/private -Inumpy/core/src -Inumpy/core -Inumpy/core/src/npymath -Inumpy/core/src/multiarray -Inumpy/core/src/umath -Inumpy/core/src/npysort -Inumpy/core/include -I/nlu/users/indrani_gorti/prefix/include/python2.7 -c'
        gcc: _configtest.c
        gcc -pthread _configtest.o -o _configtest
        _configtest
        failure.
        removing: _configtest.c _configtest.o _configtest
        building data_files sources
        build_src: building npy-pkg config files
    
    Installing collected packages: numpy
      Running setup.py install for numpy
        Running from numpy source directory.
        non-existing path in 'numpy/distutils': 'site.cfg'
        F2PY Version 2
        blas_opt_info:
        blas_mkl_info:
          libraries mkl,vml,guide not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64', '/usr/lib']
          NOT AVAILABLE
    
        atlas_blas_threads_info:
        Setting PTATLAS=ATLAS
          libraries ptf77blas,ptcblas,atlas not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64/atlas', '/usr/lib64/sse2', '/usr/lib64', '/usr/lib/sse2', '/usr/lib']
          NOT AVAILABLE
    
        atlas_blas_info:
          libraries f77blas,cblas,atlas not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64/atlas', '/usr/lib64/sse2', '/usr/lib64', '/usr/lib/sse2', '/usr/lib']
          NOT AVAILABLE
    
        /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/numpy/distutils/system_info.py:1494: UserWarning:
            Atlas (http://math-atlas.sourceforge.net/) libraries not found.
            Directories to search for the libraries can be specified in the
            numpy/distutils/site.cfg file (section [atlas]) or by setting
            the ATLAS environment variable.
          warnings.warn(AtlasNotFoundError.__doc__)
        blas_info:
          FOUND:
            libraries = ['blas']
            library_dirs = ['/usr/lib64']
            language = f77
    
          FOUND:
            libraries = ['blas']
            library_dirs = ['/usr/lib64']
            define_macros = [('NO_ATLAS_INFO', 1)]
            language = f77
    
        lapack_opt_info:
        lapack_mkl_info:
        mkl_info:
          libraries mkl,vml,guide not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64', '/usr/lib']
          NOT AVAILABLE
    
          NOT AVAILABLE
    
        atlas_threads_info:
        Setting PTATLAS=ATLAS
          libraries ptf77blas,ptcblas,atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
          libraries lapack_atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
          libraries ptf77blas,ptcblas,atlas not found in /usr/local/lib64
          libraries lapack_atlas not found in /usr/local/lib64
          libraries ptf77blas,ptcblas,atlas not found in /usr/local/lib
          libraries lapack_atlas not found in /usr/local/lib
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib64/atlas
          libraries lapack_atlas not found in /usr/lib64/atlas
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib64/sse2
          libraries lapack_atlas not found in /usr/lib64/sse2
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib64
          libraries lapack_atlas not found in /usr/lib64
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib/sse2
          libraries lapack_atlas not found in /usr/lib/sse2
          libraries ptf77blas,ptcblas,atlas not found in /usr/lib
          libraries lapack_atlas not found in /usr/lib
        numpy.distutils.system_info.atlas_threads_info
          NOT AVAILABLE
    
        atlas_info:
          libraries f77blas,cblas,atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
          libraries lapack_atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
          libraries f77blas,cblas,atlas not found in /usr/local/lib64
          libraries lapack_atlas not found in /usr/local/lib64
          libraries f77blas,cblas,atlas not found in /usr/local/lib
          libraries lapack_atlas not found in /usr/local/lib
          libraries f77blas,cblas,atlas not found in /usr/lib64/atlas
          libraries lapack_atlas not found in /usr/lib64/atlas
          libraries f77blas,cblas,atlas not found in /usr/lib64/sse2
          libraries lapack_atlas not found in /usr/lib64/sse2
          libraries f77blas,cblas,atlas not found in /usr/lib64
          libraries lapack_atlas not found in /usr/lib64
          libraries f77blas,cblas,atlas not found in /usr/lib/sse2
          libraries lapack_atlas not found in /usr/lib/sse2
          libraries f77blas,cblas,atlas not found in /usr/lib
          libraries lapack_atlas not found in /usr/lib
        numpy.distutils.system_info.atlas_info
          NOT AVAILABLE
    
        /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/numpy/distutils/system_info.py:1408: UserWarning:
            Atlas (http://math-atlas.sourceforge.net/) libraries not found.
            Directories to search for the libraries can be specified in the
            numpy/distutils/site.cfg file (section [atlas]) or by setting
            the ATLAS environment variable.
          warnings.warn(AtlasNotFoundError.__doc__)
        lapack_info:
          FOUND:
            libraries = ['lapack']
            library_dirs = ['/usr/lib64']
            language = f77
    
          FOUND:
            libraries = ['lapack', 'blas']
            library_dirs = ['/usr/lib64']
            define_macros = [('NO_ATLAS_INFO', 1)]
            language = f77
    
        unifing config_cc, config, build_clib, build_ext, build commands --compiler options
        unifing config_fc, config, build_clib, build_ext, build commands --fcompiler options
        build_src
        building py_modules sources
        building library "npymath" sources
        customize Gnu95FCompiler
        Found executable /usr/bin/gfortran
        customize Gnu95FCompiler
        customize Gnu95FCompiler using config
        C compiler: gcc -pthread -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/nlu/users/indrani_gorti/prefix/include -fPIC -fPIC   
        compile options: '-DNO_ATLAS_INFO=1 -Inumpy/core/include -Ibuild/src.linux-x86_64-2.7/numpy/core/include/numpy -Inumpy/core/src/private -Inumpy/core/src -Inumpy/core -Inumpy/core/src/npymath -Inumpy/core/src/multiarray -Inumpy/core/src/umath -Inumpy/core/src/npysort -Inumpy/core/include -I/nlu/users/indrani_gorti/prefix/include/python2.7 -Ibuild/src.linux-x86_64-2.7/numpy/core/src/multiarray -Ibuild/src.linux-x86_64-2.7/numpy/core/src/umath -c'
        gcc: numpy/linalg/lapack_litemodule.c
        gcc: numpy/linalg/python_xerbla.c
        /usr/bin/gfortran -Wall -L/nlu/users/indrani_gorti/prefix/lib build/temp.linux-x86_64-2.7/numpy/linalg/lapack_litemodule.o build/temp.linux-x86_64-2.7/numpy/linalg/python_xerbla.o -L/usr/lib64 -L/nlu/users/indrani_gorti/prefix/lib -Lbuild/temp.linux-x86_64-2.7 -llapack -lblas -lpython2.7 -lgfortran -o build/lib.linux-x86_64-2.7/numpy/linalg/lapack_lite.so
        /usr/lib/gcc/x86_64-redhat-linux/4.1.2/libgfortranbegin.a(fmain.o): In function `main':
        (.text+0xa): undefined reference to `MAIN__'
        collect2: ld returned 1 exit status
        /usr/lib/gcc/x86_64-redhat-linux/4.1.2/libgfortranbegin.a(fmain.o): In function `main':
        (.text+0xa): undefined reference to `MAIN__'
        collect2: ld returned 1 exit status
        error: Command "/usr/bin/gfortran -Wall -L/nlu/users/indrani_gorti/prefix/lib build/temp.linux-x86_64-2.7/numpy/linalg/lapack_litemodule.o build/temp.linux-x86_64-2.7/numpy/linalg/python_xerbla.o -L/usr/lib64 -L/nlu/users/indrani_gorti/prefix/lib -Lbuild/temp.linux-x86_64-2.7 -llapack -lblas -lpython2.7 -lgfortran -o build/lib.linux-x86_64-2.7/numpy/linalg/lapack_lite.so" failed with exit status 1
        Complete output from command /nrg5/nlu/data/users/indrani_gorti/venv/venv/bin/python -c "import setuptools;__file__='/nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-o4oHZQ-record/install-record.txt --single-version-externally-managed --install-headers /nrg5/nlu/data/users/indrani_gorti/venv/venv/include/site/python2.7:
        Running from numpy source directory.
    
    non-existing path in 'numpy/distutils': 'site.cfg'
    
    F2PY Version 2
    
    blas_opt_info:
    
    blas_mkl_info:
    
      libraries mkl,vml,guide not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64', '/usr/lib']
    
      NOT AVAILABLE
    
    
    
    atlas_blas_threads_info:
    
    Setting PTATLAS=ATLAS
    
      libraries ptf77blas,ptcblas,atlas not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64/atlas', '/usr/lib64/sse2', '/usr/lib64', '/usr/lib/sse2', '/usr/lib']
    
      NOT AVAILABLE
    
    
    
    atlas_blas_info:
    
      libraries f77blas,cblas,atlas not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64/atlas', '/usr/lib64/sse2', '/usr/lib64', '/usr/lib/sse2', '/usr/lib']
    
      NOT AVAILABLE
    
    
    
    /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/numpy/distutils/system_info.py:1494: UserWarning:
    
        Atlas (http://math-atlas.sourceforge.net/) libraries not found.
    
        Directories to search for the libraries can be specified in the
    
        numpy/distutils/site.cfg file (section [atlas]) or by setting
    
        the ATLAS environment variable.
    
      warnings.warn(AtlasNotFoundError.__doc__)
    
    blas_info:
    
      FOUND:
    
        libraries = ['blas']
    
        library_dirs = ['/usr/lib64']
    
        language = f77
    
      FOUND:
    
        libraries = ['blas']
    
        library_dirs = ['/usr/lib64']
    
        define_macros = [('NO_ATLAS_INFO', 1)]
    
        language = f77
    
    lapack_opt_info:
    
    lapack_mkl_info:
    
    mkl_info:
    
      libraries mkl,vml,guide not found in ['/nrg5/nlu/data/users/indrani_gorti/venv/venv/lib', '/usr/local/lib64', '/usr/local/lib', '/usr/lib64', '/usr/lib']
    
      NOT AVAILABLE
    
    
    
      NOT AVAILABLE
    
    
    
    atlas_threads_info:
    
    Setting PTATLAS=ATLAS
    
      libraries ptf77blas,ptcblas,atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
    
      libraries lapack_atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
    
      libraries ptf77blas,ptcblas,atlas not found in /usr/local/lib64
    
      libraries lapack_atlas not found in /usr/local/lib64
    
      libraries ptf77blas,ptcblas,atlas not found in /usr/local/lib
    
      libraries lapack_atlas not found in /usr/local/lib
    
      libraries ptf77blas,ptcblas,atlas not found in /usr/lib64/atlas
    
      libraries lapack_atlas not found in /usr/lib64/atlas
    
      libraries ptf77blas,ptcblas,atlas not found in /usr/lib64/sse2
    
      libraries lapack_atlas not found in /usr/lib64/sse2
    
      libraries ptf77blas,ptcblas,atlas not found in /usr/lib64
    
      libraries lapack_atlas not found in /usr/lib64
    
      libraries ptf77blas,ptcblas,atlas not found in /usr/lib/sse2
    
      libraries lapack_atlas not found in /usr/lib/sse2
    
      libraries ptf77blas,ptcblas,atlas not found in /usr/lib
    
      libraries lapack_atlas not found in /usr/lib
    
    numpy.distutils.system_info.atlas_threads_info
    
      NOT AVAILABLE
    
    
    
    atlas_info:
    
      libraries f77blas,cblas,atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
    
      libraries lapack_atlas not found in /nrg5/nlu/data/users/indrani_gorti/venv/venv/lib
    
      libraries f77blas,cblas,atlas not found in /usr/local/lib64
    
      libraries lapack_atlas not found in /usr/local/lib64
    
      libraries f77blas,cblas,atlas not found in /usr/local/lib
    
      libraries lapack_atlas not found in /usr/local/lib
    
      libraries f77blas,cblas,atlas not found in /usr/lib64/atlas
    
      libraries lapack_atlas not found in /usr/lib64/atlas
    
      libraries f77blas,cblas,atlas not found in /usr/lib64/sse2
    
      libraries lapack_atlas not found in /usr/lib64/sse2
    
      libraries f77blas,cblas,atlas not found in /usr/lib64
    
      libraries lapack_atlas not found in /usr/lib64
    
      libraries f77blas,cblas,atlas not found in /usr/lib/sse2
    
      libraries lapack_atlas not found in /usr/lib/sse2
    
      libraries f77blas,cblas,atlas not found in /usr/lib
    
      libraries lapack_atlas not found in /usr/lib
    
    numpy.distutils.system_info.atlas_info
    
      NOT AVAILABLE
    
    
    
    /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/numpy/distutils/system_info.py:1408: UserWarning:
    
        Atlas (http://math-atlas.sourceforge.net/) libraries not found.
    
        Directories to search for the libraries can be specified in the
    
        numpy/distutils/site.cfg file (section [atlas]) or by setting
    
        the ATLAS environment variable.
    
      warnings.warn(AtlasNotFoundError.__doc__)
    
    lapack_info:
    
      FOUND:
    
        libraries = ['lapack']
    
        library_dirs = ['/usr/lib64']
    
        language = f77
    
      FOUND:
    
        libraries = ['lapack', 'blas']
    
        library_dirs = ['/usr/lib64']
    
        define_macros = [('NO_ATLAS_INFO', 1)]
    
        language = f77
    
    running install
    
    running build
    
    running config_cc
    
    unifing config_cc, config, build_clib, build_ext, build commands --compiler options
    
    running config_fc
    
    unifing config_fc, config, build_clib, build_ext, build commands --fcompiler options
    
    running build_src
    
    build_src
    
    building py_modules sources
    
    building library "npymath" sources
    
    customize Gnu95FCompiler
    
    Found executable /usr/bin/gfortran
    
    customize Gnu95FCompiler
    
    customize Gnu95FCompiler using config
    
    C compiler: gcc -pthread -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/nlu/users/indrani_gorti/prefix/include -fPIC -fPIC
    
    
    
    compile options: '-Inumpy/core/src/private -Inumpy/core/src -Inumpy/core -Inumpy/core/src/npymath -Inumpy/core/src/multiarray -Inumpy/core/src/umath -Inumpy/core/src/npysort -Inumpy/core/include -I/nlu/users/indrani_gorti/prefix/include/python2.7 -c'
    
    gcc: _configtest.c
    
    gcc -pthread _configtest.o -o _configtest
    
    success!
    
    removing: _configtest.c _configtest.o _configtest
    
    C compiler: gcc -pthread -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/nlu/users/indrani_gorti/prefix/include -fPIC -fPIC
    compile options: '-Inumpy/core/src/private -Inumpy/core/src -Inumpy/core -Inumpy/core/src/npymath -Inumpy/core/src/multiarray -Inumpy/core/src/umath -Inumpy/core/src/npysort -Inumpy/core/include -I/nlu/users/indrani_gorti/prefix/include/python2.7 -c'
    
    gcc: _configtest.c
    
    _configtest.c:1: warning: conflicting types for built-in function 'exp'
    
    gcc -pthread _configtest.o -o _configtest
    
    _configtest.o: In function `main':
    
    /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/_configtest.c:6: undefined reference to `exp'
    
    collect2: ld returned 1 exit status
    
    _configtest.o: In function `main':
    
    /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/_configtest.c:6: undefined reference to `exp'
    
    collect2: ld returned 1 exit status
    
    failure.
    
    removing: _configtest.c _configtest.o
    
    C compiler: gcc -pthread -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/nlu/users/indrani_gorti/prefix/include -fPIC -fPIC
    compile options: '-Inumpy/core/src/private -Inumpy/core/src -Inumpy/core -Inumpy/core/src/npymath -Inumpy/core/src/multiarray -Inumpy/core/src/umath -Inumpy/core/src/npysort -Inumpy/core/include -I/nlu/users/indrani_gorti/prefix/include/python2.7 -c'
    
    gcc: _configtest.c
    
    _configtest.c:1: warning: conflicting types for built-in function 'exp'
    
    gcc -pthread _configtest.o -lm -o _configtest
    
    success!
    
    removing: _configtest.c _configtest.o _configtest
    
    building library "npysort" sources
    
    building extension "numpy.core._dummy" sources
    
      adding 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/config.h' to sources.
    
      adding 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/_numpyconfig.h' to sources.
    
    executing numpy/core/code_generators/generate_numpy_api.py
    
      adding 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/__multiarray_api.h' to sources.
    
    numpy.core - nothing done with h_files = ['build/src.linux-x86_64-2.7/numpy/core/include/numpy/config.h', 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/_numpyconfig.h', 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/__multiarray_api.h']
      adding 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/config.h' to sources.
    
      adding 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/_numpyconfig.h' to sources.
    
    executing numpy/core/code_generators/generate_numpy_api.py
    
      adding 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/__multiarray_api.h' to sources.
    
    executing numpy/core/code_generators/generate_ufunc_api.py
    
      adding 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/__ufunc_api.h' to sources.
    
    numpy.core - nothing done with h_files = ['build/src.linux-x86_64-2.7/numpy/core/include/numpy/config.h', 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/_numpyconfig.h', 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/__multiarray_api.h', 'build/src.linux-x86_64-2.7/numpy/core/include/numpy/__ufunc_api.h']
    
    building extension "numpy.core._dotblas" sources
    
    building extension "numpy.core.umath_tests" sources
    
    building extension "numpy.core.multiarray_tests" sources
    
    building extension "numpy.lib._compiled_base" sources
    
    building extension "numpy.numarray._capi" sources
    
    building extension "numpy.fft.fftpack_lite" sources
    
    /usr/bin/gfortran -Wall -L/nlu/users/indrani_gorti/prefix/lib build/temp.linux-x86_64-2.7/numpy/linalg/lapack_litemodule.o build/temp.linux-x86_64-2.7/numpy/linalg/python_xerbla.o -L/usr/lib64 -L/nlu/users/indrani_gorti/prefix/lib -Lbuild/temp.linux-x86_64-2.7 -llapack -lblas -lpython2.7 -lgfortran -o build/lib.linux-x86_64-2.7/numpy/linalg/lapack_lite.so
    
    /usr/lib/gcc/x86_64-redhat-linux/4.1.2/libgfortranbegin.a(fmain.o): In function `main':
    
    (.text+0xa): undefined reference to `MAIN__'
    
    collect2: ld returned 1 exit status
    
    /usr/lib/gcc/x86_64-redhat-linux/4.1.2/libgfortranbegin.a(fmain.o): In function `main':
    
    (.text+0xa): undefined reference to `MAIN__'
    
    collect2: ld returned 1 exit status
    
    error: Command "/usr/bin/gfortran -Wall -L/nlu/users/indrani_gorti/prefix/lib build/temp.linux-x86_64-2.7/numpy/linalg/lapack_litemodule.o build/temp.linux-x86_64-2.7/numpy/linalg/python_xerbla.o -L/usr/lib64 -L/nlu/users/indrani_gorti/prefix/lib -Lbuild/temp.linux-x86_64-2.7 -llapack -lblas -lpython2.7 -lgfortran -o build/lib.linux-x86_64-2.7/numpy/linalg/lapack_lite.so" failed with exit status 1
    
    ----------------------------------------
    Command /nrg5/nlu/data/users/indrani_gorti/venv/venv/bin/python -c "import setuptools;__file__='/nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-o4oHZQ-record/install-record.txt --single-version-externally-managed --install-headers /nrg5/nlu/data/users/indrani_gorti/venv/venv/include/site/python2.7 failed with error code 1 in /nrg5/nlu/data/users/indrani_gorti/venv/venv/build/numpy
    Storing complete log in /home/indrani_gorti/.pip/pip.log
    


Answer: CFLAGS AND LDFLAGS in your bashrc file have to be unset. Then pip install
numpy works.

