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:
            version = self.__version.replace('.', '-')
            if self.__cuda_multi:
                self.__nvhpc_package = 'nvhpc-{}-cuda-multi'.format(version)
            else:
                self.__nvhpc_package = 'nvhpc-{}'.format(version)

            if not self.__ospackages:
                if self.package or self.__tarball:
                    self.__ospackages = ['bc', 'debianutils', 'gcc', 'g++',
                                         'gfortran', 'libatomic1', 'libnuma1',
                                         'openssh-client', 'wget']
                else:
                    self.__ospackages = ['ca-certificates', 'gnupg', 'wget']
            self.__runtime_ospackages = ['libatomic1', 'libnuma1',
                                         'openssh-client']
        elif hpccm.config.g_linux_distro == linux_distro.CENTOS:
            if self.__cuda_multi:
                self.__nvhpc_package = 'nvhpc-cuda-multi-{}'.format(self.__version)
            else:
                self.__nvhpc_package = 'nvhpc-{}'.format(self.__version)

            if not self.__ospackages:
                if self.package or self.__tarball:
                    self.__ospackages = ['bc', 'gcc', 'gcc-c++',
                                         'gcc-gfortran', 'libatomic',
                                         'openssh-clients', 'numactl-libs',
                                         'wget', 'which']
                else:
                    self.__ospackages = ['ca-certificates']
            self.__runtime_ospackages = ['libatomic', 'numactl-libs',
                                         'openssh-clients']
        else: # pragma: no cover
            raise RuntimeError('Unknown Linux distribution')
Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults.
hpccm/building_blocks/nvhpc.py