def _domcmc(input_tuple):
    """Function to be run in parallel on different CPUs
    Input is a tuple: first element is an emcee sampler object, second is an array of
    initial positions, third is number of steps to run before doing a convergence check
    """
    sampler = input_tuple[0]
    ipos = input_tuple[1]
    check_interval = input_tuple[2]
    sampler.run_mcmc(ipos, check_interval)
    return sampler
