Run D8 horizontal distance down to stream.

def d8hdisttostrm(np, p, src, dist, thresh, workingdir=None,
                      mpiexedir=None, exedir=None, log_file=None, runtime_file=None, hostfile=None):
        """Run D8 horizontal distance down to stream.
        """
        fname = TauDEM.func_name('d8hdisttostrm')
        return TauDEM.run(FileClass.get_executable_fullpath(fname, exedir),
                          {'-p': p, '-src': src},
                          workingdir,
                          {'-thresh': thresh},
                          {'-dist': dist},
                          {'mpipath': mpiexedir, 'hostfile': hostfile, 'n': np},
                          {'logfile': log_file, 'runtimefile': runtime_file})