def __distro(self):
        """Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults."""

        if hpccm.config.g_linux_distro == linux_distro.UBUNTU:
            if not self.__ospackages:
                self.__ospackages = ['gcc', 'g++', 'libnuma1', 'perl']
                if self.__mpi:
                    self.__ospackages.append('openssh-client')
            self.__runtime_ospackages = ['libnuma1']
            if self.__mpi:
                self.__runtime_ospackages.append('openssh-client')
            self.__libnuma_path = '/usr/lib/x86_64-linux-gnu'
        elif hpccm.config.g_linux_distro == linux_distro.CENTOS:
            if not self.__ospackages:
                self.__ospackages = ['gcc', 'gcc-c++', 'numactl-libs', 'perl']
                if self.__mpi:
                    self.__ospackages.append('openssh-clients')
            self.__runtime_ospackages = ['numactl-libs']
            if self.__mpi:
                self.__runtime_ospackages.append('openssh-clients')
            self.__libnuma_path = '/usr/lib64'
        else:
            raise RuntimeError('Unknown Linux distribution')
Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults.
hpccm/building_blocks/pgi.py